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is the Journal of the Biological Society, Victoria University of Wellington, New Zealand, and is published three times a year, with the financial assistance of the University Publications fund.
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When the Russian research vessel Vitiaz visited Wellington in 1958 Dr. Georgei Beliaev exhibited specimens of Pogonophora, a group of marine worm-like animals now considered to comprise a distinct phylum, possibly related to Enteropneusta. Prior to the Russian visit no Pogonophora had been recorded from New Zealand, and a detailed account of them is still awaited.
The class Pogonophora was proposed in 1937 by Johansson to accommodate a peculiar worm-like animal Lamellisabella which previously had been described as a Polychaete. The present leading authority on them is Professor Siboglinum weberi, was a Pogonophoran; it had been collected by the Siboga in 1899-1900 in deep water off Malaya, and was thus the earliest example known to science.
Opinion is at present divided as to how these animals should be oriented. In this article I follow Ivanov and Ulrich, who regard the nerve cord as dorsal and the tentacles as ventral. The reverse orientation is preferred by Caullery, Dawydoff and Jagersten.
Pogonophora appear to be sedentary, non-colonial, tubicolous marine coelomates with an elongate, bilaterally symmetrical, cylindrical body divided into three regions or segments. The first segment, or prosoma, is very short, and contains an unpaired coelomic pouch which extends into either a single tentacle or, more usually, a tuft of tentacles. The second segment, or mesosoma, is also short; it contains a pair of coelomic pouches. The posterior segment, the trunk or metasoma, is very long and contains a pair of coelomic pouches, each housing a gonad. There is no alimentary canal, mouth or anus, the function of nutrition and respiration being performed by the vascular tentacles of the prosoma. There is a well-developed vascular system and a dorsal nerve-cord. The life-history includes a free-swimming larva within which a vestigial, solid endodermal mass has been recognised.
Although one species, Siboglinum ekmani Jagersten, occurs off the Norwegian coast in water as shallow as 98 fathoms, most species are known from the deep-sea trenches of the North Pacific, where they are sometimes exceedingly abundant. Most species are no more than 1 mm. wide and several centimetres long, but large forms reach a length of about a metre.
The tube is long and cylindrical. It appears to be a secreted structure of a brittle, membranous substance, characterised (in Siboglinum) by
alternating brownish and translucent transverse rings; distally the tube is thinner and more transparent, with transverse bars of darker material at wide intervals. The body-wall is covered by a hypodermis which secretes a chitinous cuticle, save on the tentacles, where the ectoderm cells form a ciliated epithelium. Within lie muscle-fibres, apparently longitudinal for the most part.
The vascular system is a closed one. Blood flows forwards in the median ventral vessel, enters the heart, circulates through the afferent and efferent tentacular vessels, and then passes into the median dorsal vessel, where it flows backwards. Short blind vessels supply the prosoma. In the trunk a pair of vessels supply the gonads, and at the posterior end of the body the ventral and dorsal vessels unite in a rete. Some genera have a contractile pericardial vesicle beside the heart.
Nutrition: The absence of an alimentary canal was a puzzle to the earlier investigators. Caullery (1914, 1944) thought that the individual he had received from the Siboga expedition must have been part of a colony whose nutritive zooids had not been collected. Later, Dawydoff (1948) concluded that there was no digestive system; but it was left to Ivanov (1952) to infer that the tentacles were probably the nutritive organs. In 1955 Ivanov suggested that the tentacles arrange themselves in such a way as to form a tube, into which the food material is taken and digested by enzymes secreted by gland-cells on the tentacles. In Lamellisabella a tube of this type is a permanent feature, as the tentacles are coalesced in that genus. An alternative suggestion by Jagersten (1957) is that Pogonophora may be saprozoic, the tentacles merely absorbing soluble substances produced as a result of bacterial activity on dead material on the sea-floor.
The nervous system resembles that of the Enteropneusta. There is a ganglion on the dorsal side of the prosoma. From it arise a pair of lateral commissures which supply the tentacles, and a median dorsal nerve-cord which runs backwards into the other segments.
The excretory organs comprise a pair of ciliated coelomoducts in the prosoma. These are united medially by a transverse canal, and open separately to the exterior, each by a lateral coelomopore. In Siboglinum and some other genera the coelomoducts are widely separated and lie in the posterolateral part of the prosoma; in these forms a pericardial vesicle occurs beside the heart. In Polybrachia and the remaining Pogonophora,
Reproductive system: The sexes are separate. The paired gonads lie in the metasoma. In the male the testes occupy the whole posterior part of the body. From each testis a long, ciliated gonoduct runs forwards to the anterior part of the metasoma, where it opens ventrally. In the female the ovaries lie in the anterior part of the metasoma, the short oviducts running posteriorly to open about midway along its length. The eggs are relatively large and yolky.
The larval form (Figs. 3a and 3b) has been desbribed by Jagersten (1957) for Siboglinum ekmani. There is a temporary pelagic stage, swimming by means of an anterior and a posterior ring of cilia. The voluminous, yolk-laden intestine lies within, and an anterior invagination may be the vestige of the mouth. Each of the segments carries paired setae similar to those of annelids. No tentacle is developed at this stage. Three such larvae were observed in the distal part of the tube of an adult female, and it was evident that they would have been extruded when next the parent extended her tentacle (there is only one tentacle in Siboglinum).
Up to 1956 five families of Pogonophora had been defined by Ivanov, eighteen species being arranged in eight genera, as follows: Fam. Siboglinidae (Siboglinum); Fam. Oligobrachiidae (Oligobrachia, Birsteinia); Polybrachiidae (Polybrachia, Heptabrachia); Lamellisabellidae (Lamellisabella); Spirobrachiidae (Spirobrachia). Kirkegaard (1956) has since added a ninth genus, Galathealinum.
Although Hartmann (1954) has suggested that Pogonophora may be no more than a heterogeneous artificial assemblage of aberrant Polychaeta, this view has not been supported. Ivanov himself (1954), after drawing attention to the distinctive characters shared by all known Pogonophora, considers that they should constitute an independent phylum (which he names Brachiata) diagnosed by the presence of vascular anterior tentacles, serving as respiratory and digestive organs.
Jagersten (1956, 1957) regards the Pogonophora as a distinct group, perhaps related to but not members of the Enteropneusta. Although he admits the presence in the larva of setae of the annelid type, he points out that such setae occur also in Brachiopoda, and rejects Hartman's suggestion that Pogonophora are Polychaetes. After his discovery of the larval stage Jagersten (1957) re-examined the problem. He concluded that since the larva is 3-segmented, like its adult, it cannot be a modified Trochophore; a further argument against annelid affinities. He notes the vague resemblance of the larva to that of some Enteropneusta but, lacking information on the range of types of larvae or their possible specialisation, he sees no grounds for believing Enterpneusta and Pogonophora to be
Acknowledgment: I wish to thank Dr. N. Danilow and Mr. S. Kustanowicz for translating passages from relevant Russian papers; Dr. Georgei Beliaev for drawing our attention to the Pogonophora; and Prof. G. Jagersten for data on Siboglinum ekmani.
The bewildering array of small-leaved tangled shrubs which are so common in the New Zealand bush present a real problem when one comes to identify them. They are botanically diverse yet so strikingly similar in habit that their fine distinctions require very careful study. Most people will come to recognise only two kinds, Coprosmas and the rest.
These ‘wiggy’ bushes or mikimikis are of rare occurrence in overseas floras excepting that of Tasmania, which has some resemblance to New Zealand in coastal and alpine areas. Botanists describe them as divaricating, a term derived from Latin meaning ‘stretched apart’. It refers to the branching, where branchlets diverge at an angle of 90°or more from the main axis. Divaricating shrubs usually form an inseparably interlaced mass of twigs. The leaves are small, and the branches, although always tough, may vary from rigid and spiny with frequent branching to wiry or flexible with occasional branching. The habit is well fitted for survival in exposed situations, and is found most commonly in plants of the sea coast and mountains. Divaricating shrubs are largely responsible for the distinctly weird appearance of some vegetation. They have not yet been found to have economically useful properties, except that they do act as stabilisers on soil exposed to severe erosion.
The divaricating form is not sharply defined but grades into the normally branched small-leaved shrub, so that there are intermediate forms difficult to classify. Manuka is not normally divaricating, but when growing exposed to wind or salt spray which kill back the young shoots it becomes a closely branched wind-shorn mass very similar to the truly divaricating shrubs of the same habitat. At extremes of exposure the ultimate branchlets of Aristotelia fruticosa become spines, but on the other hand the same shrub loses its divaricating nature and spines, and becomes more lax, open and leafy when growing in the protection of the forest. Amongst scrub communities one may come across barbed-wire entanglements of almost leafless stems belonging to species of Rubus, Clematis or Muehlenbeckia, which in sheltered conditions are climbing plants. The hummocks formed by these lianes look like divaricating shrubs. Thus the habit of any species is not necessarily fixed, but often varies according to habitat.
Some shrubs remain divaricating throughout their life, while others are merely the juvenile form of a forest tree, which after a number of years will put out erect branches and pass into the adult. One common type of development in such plants involves three stages of growth, a normal
Elaeocarpus hookerianus), and an adult tree form. This sequence is found in Sophora microphylla, Pennantia corymbosa and
The divaricating form occurs in widely different plant families and is often peculiar to the New Zealand members of a family or genus. Because divaricating shrubs appear to be adapted to conditions of low humidity and extremes of temperature rather than to the present mild New Zealand climate. Cockayne speculated that the habit arose in a former geological age as a response to a dry continental climate, and has persisted through the subsequent climatic change. There is some doubt whether this elaborate explanation is necessary, since the strong winds experienced at the present day in the typical habitat of divaricating shrubs may cause conditions approaching the continental.
Plants are recognised and classified most surely by their reproductive structures. This is particularly true of divaricating shrubs since examples from different families come to resemble one another so closely when not in flower or fruit that they are difficult to distinguish. However, in order to be more generally useful, the accompanying key to divaricating shrubs makes use of vegetative characters for identification at least to the generic level, though within the genera Olearia and Pittosporum it has not been possible to avoid using some flower and fruit characters.
The shrubs in the key fall into two main groups, those with alternate leaves forming section A, and those with opposite paired leaves section B. Where leaves arise in clusters these fascicles are themselves correspondingly alternate or opposite. The leaf arrangement of Aristotelia fruticosa may present some difficulty as occasional branches bear a few leaves not arising exactly opposite one another, although the majority will be strictly paired.
Specimens for identification should be as fresh as possible, and not too small. It is best to collect specimens from two or three different parts of the plant to be sure of obtaining the range of leaf variation in the species.
The genera Plagianthus and Nothofagus produce hybrid forms intermediate between the species listed in the key. Olearias vary even more widely, and because the key to this genus contains only a selection of well-marked species, plants which cannot be diagnosed will be either uncommon and not listed, hybrids, or horticultural varieties.
In deciding whether stipules are present or absent it must be borne in mind that they may be very small, or early deciduous. It will be necessary to examine the bases of developing or newly expanded leaves at the tips of the branches, preferably with a pocket magnifier. Withered specimens may be impossible to investigate for stipules. In such cases it is best to follow out the key for both possibilities and then decide from the final descriptions which of the two answers is correct. For full details of any species, always consult a standard flora. The importance of minute observation with a lens cannot be too strongly emphasised. It is only to the casual observer that divaricating shrubs present a baffling uniformity.
In this article no attempt is made to cover all features of close-up photography; instead, emphasis is placed on some of its lesser known but equally important aspects. Only the 35 mm. camera is considered, and attention is paid mainly to colour photography. The equipment required is simple vet must be reliable, and as much of it will have to be constructed in the laboratory, one should remember that good workmanship will bring its own reward.
For convenience the items of equipment listed below are considered under two main headings, but it must be realised that a certain amount of overlap is inevitable.
As with all equipment for use in the field, the camera must have lightness and rigidity. The 35 mm. is a good answer to both of these. It must also have an efficient focussing device complete with either a reflex mirror or a rangefinder.
Essential requirements are good resolving power and definition, with a focal length not too short. It is a distinct advantage, particularly with small animals such as insects, etc., to be able to photograph them from a distance, thus avoiding any undue disturbance of the subject. Also, a short-focus lens tends to give distortion at close range, as well as allowing too little space for manoeuvring between lens and subject.
The Makro Kilar lens, which will fit several cameras, is a good example, and. although it is inclined to be a little too short in the focal length, has proved very useful indeed for quick work and easy manipulation. Its chief attributes are an incorporated extension tube mounted on a helical device, and an exposure factor scale which immediately indicates the amount of increase in exposure due to increased lens-to-film distance when working close up. The increase in exposure is necessary because a law similar to the Law of the Inverse Square applies as well to lens-to-film distance as to light-to-subject distance. Thus when a camera is racked out to twice the focal length of the lens, the exposure will need to be exactly X4 normal, and so X4 focal length necessitates X16 exposure. The Makro Kilar lens covers a whole range of distances from infinity down to 2 inches.
The purpose of a supplementary lens is to decrease the focal length of the camera lens and so, with the same lens extension, enable one to focus on nearer objects. This is necessary on cameras which do not allow the use of focussing bellows or extension tubes. Under such conditions difficulties in focussing immediately arise, but in cameras such as the ‘Paxette’ these are taken care of by the use of corresponding prisms attached to the rangefinder, thus coupling the rangefinder down to the necessary short focussing distance.
An additional advantage in the use of supplementary lenses is that when used in conjunction with focussing bellows or extension tubes, the lens-to-film distance is reduced and more rapid exposures are possible. Unfortunately, in every case definition of the image is impaired.
This must be rigid, even though for field work it be of light construction. Unfortunately, most light tripods are useless. Either a pan. and tilt head or a universal joint is a virtual necessity. Many good pictures are taken with the camera held in the hand, but too many have been ruined by the ‘slightly blurred’ image.
Steadying the camera by means of a foot strap, the use of a ‘unipod’ or a pistol grip (Fig. 4) are all reasonably good substitutes. Generally with the use of an electronic flash the need for mechanical support becomes less, although in such cases I often use a pistol grip.
Electronic flash. Advantages— high speed and low running cost. Disadvantages— high initial cost and additional weight; also there is a tendency for batteries to deteriorate when not in use.
Flash gun. Advantage— low initial cost and greater output of light. In working at close range, the latter is of doubtful advantage without a tripod. Disadvantage— high running cost. If the choice is electronic flash, it must have a flash duration of not less than 1/500 sec. in order to eliminate camera shake. Ring flash overcomes the tendency towards uneven distribution of lighting, but unfortunately produces extremely flat, uninteresting results.
Choose a good one— it pays.
For black and white— standard filters, and polarising. For colour— conversion filters, ultra violet and polarising.
In colour work I have had excellent results from the use of Lifa filters, in conjunction with a Lifa colour temperature meter. With this combination it is possible to adjust any discrepancy between the colour temperature of the light source and that for which the colour film is balanced. The pale
The first to come to mind is a wire frame (Fig. 1), fitted to the front of the camera at a predetermined distance, constructed to enable the photographer to place it over the subject (e.g. an insect) and release the shutter in a minimum of time. The subject should be in the centre of the rectangle, the perimeter of which represents the format of the image on the film. Provided the lens has been set for a certain distance, the subject will automatically be in focus.
The wisdom of using a pistol grip (Fig. 4) is sometimes debated, but I have experimented with various types and feel the advantages outweigh any disadvantages. The unit should be well balanced. It may be argued that a camera cannot be held sufficiently steady in this way, but it is equally true that it does allow more freedom of action, particularly if the cable release be incorporated in the hand portion of the grip, so that one may release the shutter with the same hand as the one that supports the camera. As I use an Exakta Varex fitted with a prismatic viewfinder for this type of work, I find this arrangement very effective.
If the flash be attached to the camera, the additional weight must be countered by shifting the position of the grip accordingly.
It will not always be possible, or even desirable, to include a scale in photographs, but a number of things may be resorted to, e.g. coins, matchboxes, etc., but for complete accuracy there is no substitute for a reliable scale. Good suitable scales do not appear to be very easily obtained, and it may necessitate making one. This is conveniently done by drawing a large original and reducing it down to the actual measurement by copying.
For measuring flash-to-subject distances the difficulty of using a ruler in a confined space is obviated by the use of two simple measuring devices.
Each consists of a small diameter brass rod fitting neatly inside a brass tube of approximately the same length (Fig. 6), extendable in the first to a total distance of about 9 in., and in the second to about 18 in. These are suitable for extreme close-ups only, as for greater distances than about 18 in. this principle becomes unwieldy, and secondly the need for such extreme accuracy in measuring distances for exposure is not so great.
For lens-to-subject distances shorter than X8 focal length, exposure must be increased as follows: —
(Lens - film distance/Focal length of lens) 2
Numerous scales for determining the increase in exposure due to the extension of the lens beyond its focal length have been published; but to pursue this to its logical conclusion, this vital information, relevant to the lens in use. should be transferred on to a detachable scale accompanying the camera. The exposure factor may then be read off in an instant as follows. One end of the scale will be in line with the film plane, while towards the other end will be figures representing the different positions of the lens, coinciding with the number of times exposure due to increase in extension beyond the focal length. This arrangement will be helpful, more especially when using bellows, than with tubes, as in any case each tube or combination of tubes is readily identified with an exposure factor normally supplied by the manufacturer.
A word on exposure charts (Fig. 7). Having ascertained the flash factor for a certain type of film, it is a simple matter to plot the curve on a graph. Any combination of distance and f number may be read off instantly. In Fig. 7 the film is Kodachrome daylight which is found by experiment to have a flash factor of 20 when used with a Mecablitz 36 electronic flash. In actual figures this means, say, at a flash-to-subject distance of 4 ft. the required lens aperture will be f5. By dividing any desired aperture into the flash factor of 20, we automatically have the required flash-to-subject distance in feet. Conversely, by dividing any desired flash-to-subject distance in feet into the flash factor of 20 we automatically have the required aperture. The graph can now be plotted for all combinations of distances and aperture either way. It is pointed out that the exposure can be varied by changing the aperture or the flash-to-subject distance.
For normal use the flash-to-subject distances would be in feet, but for working at close range we are obliged to divide this up into inches. Similarly, in practice I have found it convenient to divide the f numbers into thirds. As we are concerned with close distances only, and the light
We wish to use, say, a Makro Kilar 40 mm. lens at f22 to secure maximum depth of focus. With the flash at 48 in. from the subject, the correct aperture would be f5. Therefore, to compensate for the reduction of aperture to f22, this means moving the flash in to 10½ in. (see scale). This introduces at least two more factors: —
In the case of (1), extending the lens decreases the exposure by one stop; in other words, to an equivalent aperture of f32 (shown on scale as f32). As we do not wish to alter the aperture from f22, the increase in exposure is gained by shortening the flash-to-subject distance. As can be seen from the graph, the flash-to-subject distance for an aperture of f32 is 7 in., so the flash is brought in to that distance.
In the case of (2), the increase works out to 2/3 of a stop. This should be added on to the f32 that has already been calculated, and for the same reason as in (1) the flash will be moved in further again from 7 in. to 5½ in. (shown on scale as f32 + 2/3).
With some exceptions, laboratory equipment is basically the same as that used in the field.
Here we can exclude daylight. In most cases it will probably be more convenient to use Tungsten lighting. Photofloods for black and white are optional, but for artificial-light colour film there will be no choice. Possible danger of overheating the subject, by the use of photofloods, may be eliminated by using a voltage reducer for preliminary work such as focussing. A highly expensive, yet highly desirable piece of equipment for use with colour is a constant voltage transformer. This prevents ‘surge’, which upsets not only the exposure but the colour temperature as well.
The most satisfactory method of holding the camera firmly is by means of a vertical column mounted on a base board which can be swung into the horizontal position when necessary, depending on whether the subject is to be photographed from top or side. It should be constructed of rigid, heavy, but not necessarily bulky material, and mounted on a solid firm base. Vibration must be prevented at all costs, even to the extent of checking on the building itself.
In order to illustrate the functions of as many as possible of the items mentioned above, we will assume we are photographing two small but otherwise dissimilar subjects: —
Our camera for both assignments is a 35 mm. reflex, and in the first case is coupled to an electronic flash rated at 120 joules, and with a flash duration of 1/750 sec. To avoid uneven lighting, the flash is kept as closely as possible in line with the axis of the lens.
The lens is a medium-long focus 75 mm. fitted to the camera body by means of extension tubes. The whole unit is now fitted to a pistol grip.
There will be no time to do any calculations while tracking our quarry, so we must anticipate the conditions under which we will be working. Focus on a small stationary object, approximately the size of an average-sized insect, and with the help of the chart mentioned earlier measure the flash-to-subject distance on the scale constructed for this purpose. Provided nothing is altered between that moment and the moment of actual exposure, there should be little to worry about. Once the insect is in focus, the flash will automatically be at the correct distance.
The makers of more recent models of electronic flash claim they are corrected for use with colour, otherwise it will be necessary to use a pale pink correction filter such as the Lifa CR 1.5 mentioned earlier.
If our work is to be of consistently high quality, as much of it as possible should be done in the laboratory. Our problems, though many, will be more easily dealt with.
We are photographing a small flower, for which purpose we use our column and base board camera mount. The camera is loaded with colour film, and the subject this time is placed on a suitable background of a colour
A useful base on which to rest the subject and background is a focussing stage capable of controlled movement from left to right, forwards and backwards, up and down, clockwise and anti-clockwise, and tilt.
Lighting will consist of two photofloods, one as a ‘main light’ and the other as a ‘fill in’, but as we are using colour film there should not be too great a difference between their respective distances away from the subject.
A small mirror (Fig. 5), or series of mirrors, can be very helpful in reflecting light back into the odd troublesome shadows.
Fancy or bizarre effects, as contrasted to the artistic, should be avoided, but that is no reason for keeping the lighting dull and uninteresting.
Colour film has much less latitude than has black and white, but just the same it should be possible to infuse a charm and sparkle into our transparencies that will make them into something more than just mere coloured records.
Exposures will be fairly long, and in addition to any previously mentioned rules for increase in exposure, we must also allow for the phenomenon known as ‘reciprocity failure’. In black and white, owing to the exposure latitude, its effect can virtually be ignored, but in colour it is something to be recokned with. Briefly, all films are balanced to give maximum efficiency at a certain shutter speed, and any increase or decrease in that speed will produce a decrease in effective film speed.
Wallis and Beatt, 1953. Reciprocity Failure. The British Journal Photographic Almanac, 170-172.
Exposures must be brief, and although we are not bound to use electronic flash, it does have at least two advantages— speed and convenience. No vast amount of paraphernalia is necessary, but to ensure the subject is kept easily in focus, and prevented from wandering out of the picture, a ‘cage’ (Fig. 3) of some sort may be used. This should be gently lowered into the water and held firmly (with the subject inside) against one side of the tank. It is advisable to use either glass or perspex fashioned into a box, and leave one of its longer vertical sides open. If the cage is lowered so that the top of it is not lower than the level of the water, no ‘lid’ will be necessary. Conversely, if the ‘cage’ is to rest on the floor of the tank, no bottom will be needed. The photographer, if he chooses, may construct a completely new tank (Fig. 2) of a comparable size to the ‘cage’. A suggested variation is to increase the front-to-back distance of the tank over that of the ‘cage’, and insert a piece of perspex or glass slightly shorter than the length of the longest side to restrict the activities of the subject to one plane. The only virtue in this is for easy adjustment to allow for the width of the subject.
Owing to a number of factors, such as the absorption of light by water, obstruction of light by plants, refraction, etc., exposures are probably best obtained by trial and error.
To avoid reflections of light sources, lamps must be at an angle of more than 45°with the axis of the lens of the camera.
Top lighting, although not essential, is preferable to any other as it is conducive to a more natural and pleasing effect.
If photofloods are used, care must be taken not to overheat the water. Also, prolonged working with the same limited volume of water may rapidly deplete the oxygen content.
Part of this work was written at Portobello Marine Biological Station during the tenure of a Nuffield Research Grant.
The amphipods form an order of sessile-eyed Crustacea in which the great number of species is reflected by a striking variety of habitats ranging from the heights of mountain ranges to the greatest depths of the ocean. Yet the variety of morphological distinction is comparatively limited and so the classification is necessarily based on a complex of small morphological characteristics. There are certainly bizarre and weird species, but the great number of the several thousand species which have been described are of a morphological sameness conforming to three or four basic patterns, relieved in the littoral and pelagic species by an often startlingly beautiful body and eve coloration. This ephemeral beauty fades with the approach of the preservative bottle or, strangely enough, with adaptation to a supralittoral or terrestrial environment.
There are four sub-orders. The Cyamidea, called by some authors the Caprellidea, is comprised of the Cyamidae or whale-lice and the Caprellidae or skeleton shrimps. In both of these families the distinctive body shape has been achieved by reduction of segments and degeneration of appendages, with flattening of the body in the one case and rounding and elongation in the other. The Hyperiidea are large-eyed and usually transparent or violet-reddish pelagic amphipods. The Gammaridea, which are the most numerous and diverse in form, are represented particularly in the tidal and bottom regions of the ocean, but are also found in fresh water and on land. The last sub-order, the Ingolfiellidea, has not as yet been recorded from New Zealand. Although long and cylindrical in general appearance like the skeleton shrimps, the Ingolfiellidea are clearly distinguished from all other Amphipoda by the complete separation of the eyelobes from the head and by the pleopods which consist of moderately small, almost triangular plates. In addition, in both gnathopods, the fifth segment has been developed as a hand and the sixth and seventh together form a combined dactylos or claw (Hansen 1903). Altogether, some 48 families and more than 200 species of amphipods have been recorded from New Zealand, its surrounding waters and outlying islands.
Apart from studies on the classification, little work has been done on the group in New Zealand. The first species from New Zealand were described
Apart from these reports, a paper by Powell (1874), and two small papers by Kirk (1879) in the Transactions of the New Zealand Institute, the major work on the group in New Zealand was done by
Because of the great number of species and the system of classification, the amphipods are something of a specialist's group and they will probably always remain so. Nevertheless, it is possible without much trouble to track down specimens at least to family level and, after some acquaintance, to recognise many of the families on sight. At the generic level, unless the group has been recently and well covered in a general survey, difficulties in identification wall quickly pile up, especially in regard to available literature in New Zealand.
Apart from this key and the expedition reports mentioned above, useful guides to the group are the volumes on amphipods in the ‘Faune de France’ series (Chevreux and Fage, 1925); Hale's less extensive ‘Crustacea of South Australia’; and the series of papers by Barnard in the Annals of the South African Museum, especially the 1940 paper which gives extensive keys to both amphipods and isopods. These papers are valuable down to a generic level and many of the genera found in South Africa are common here, although a number of genera which occur here
Identification is based on external morphological characteristics. Unless a person is familiar with the group already, it is necessary to dissect off the animal's appendages fairly extensively. Almost all of the external characteristics which could possibly be used for identification are used, and the mouthparts are especially important. For accurate identification it is necessary to check in detail antennae, rostrum (if present), mouthparts (epistome, upper and lower lip, mandibles, first and second maxillae, and maxilliped), all seven pairs of leg appendages (generally reckoned as first and second gnathopods and first to fifth peraeopods), gills, epimeral plates, pleopods, uropods and telson. This is in addition to any peculiarities of general body shape.
Some of these terms call for explanation. The mouthparts are best explained by the figures— they lie beneath one another in the order given above. The epistome is a structure overlying the upper lip, sometimes fused with it, sometimes deeply separated from it, often in the vertical plane whereas the upper lip lies in the horizontal plane. The mandibles and first maxillae may have quite long, but usually slender, ‘palps’ attached to them or they may lack palps entirely. The maxilliped is made up of an inner and outer plate and a palp (lacking in the Hyperiidea). The maxilliped palp segments are named in the same manner as the leg appendages, i.e. basos (second), ischium (third), merus (fourth), carpus (fifth), propod (sixth), and dactylos (seventh).
The first two pairs of legs are usually greatly different from the remaining five pairs, although not so noticeably in the Hyperiidea. The sixth segment of these legs is often greatly expanded, especially in the second pair in the male. In some species, this expansion appears to be related to copulatory habits, and it is not uncommon for differences in the gnathopods to be the only obvious external morphological differences between sexes. In such species the gnathopods in the females are usually less strongly developed. The remaining legs, or peraeopods. are much more alike except for the second segment or basos. and for the first segment which is modified into a large plate fixed to the body— from which it gets its more common name of ‘sideplate’. The first and second peraeopods are usually almost identical except for sideplate shape; the third peraeopod has a distinctive bilobed sideplate in most species but its basos is like that of the fourth and fifth peraeopods which are very similar. The remaining segments are much the same in all five peraeopods but the third, fourth and fifth peraeopods are reversed compared with the first and second. These variations make it
Talorchestia which includes many of the common beach-hoppers (Family Talitridae), the fourth or fifth peraeopods often have one of the segments greatly expanded into a plate or cup, or grossly swollen. Strangely enough, this development is peculiar to the males alone and usually to adult or senescent males.
The segments bearing the pleopods are usually known collectively as the pleon. Apart from the pleopods themselves, which have considerable diagnostic value in the Talitridae where they may be greatly modified or even reduced to vestigial stumps, importance is attached to the shape of the protective plates produced down on each side from the body and corresponding somewhat to the sideplates. These are usually known as ‘epimeral plates’. The three uropods and the telson present less difficulty in nomenclature. Other terms used are explained by the diagrams which have been somewhat generalised to show clearly a type rather than refer to a specific genus or animal.
Terrestrial species are best collected by the Berlese funnel method; that is, by heating leafmould in a special funnel with a gauze platform which allows animals to pass through the gauze and down the neck of the funnel into the preservative below but prevents the leafmould from accompanying them. A heating element in the lid or a lid with water-jacket supplies the necessary stimulus to movement. Pelagic species are usually collected in plankton nets although they may be taken when attracted to a strong light at night or more rarely in shoals cast on the beach.
The most effective way of collecting littoral species is by shaking seaweed or bryozoa in sea water to which a little formalin or alcohol has been added. This is especially good for caprellids and although they do not
Alcolhol, 70% or 95%, is probably the best preservative. If the specimens are required soft a drop of glycerine will help although for systematic purposes the brittleness imparted by alcohol makes dissection with needles much easier. It has the disadvantage that appendages are liable to breakage before examination but this can usually be prevented by careful handling. Formalin has the distinct advantage of preserving colours for a considerable time. As a general rule, colour is not of great importance in classification in the amphipods but there are a few species for which it is important, and these do not usually lose their pigmentation pattern in either alcohol or formalin although the colour of the pigment may change in alcohol.
The keys which follow treat the Families of Cyamidea and of Gammaridea. The Hyperiidea have been treated in a recent paper elsewhere (see No. 11 in list of papers following key). As a general guide, the following pointers are useful. All terrestrial and supralittoral hoppers belong to the Family Talitridae, and species of this family are particularly abundant in New Zealand, especially in leafmould— the Crustacea at the bottom of the garden. These species belong to the genera Talitrus, Talorchestia and Orchestia. Fresh-water species in New Zealand are likely to belong to the Gammaridae (Phreatogammarus, Melita, Paracrangonyx), Talitridae (Chiltonia), Calliopiidae (Paracalliope, Paraleptamphopus), Pontogeneiidae (Paramoera) or Corophiidae (Paracorophium).
The keys are based on those given by Stebbing (1906) and Barnard (1940). Stebbing's monograph on the Gammaridea in the ‘Das Tierreich’ series, whilst obviously not including the great bulk of systematic work done since, is still the major work in the group but it is not easy to obtain. Because of its importance, it is worth mentioning that copies are held at Canterbury University College (Chilton Collection) and at Portobello Marine Biological Station. The first volume of the Challenger report is also very valuable; there Stebbing summarises every paper up to 1887 dealing with the group, and gives in full or in precis many otherwise unobtainable descriptions.
(The numbers in brackets after the family name refer to papers in the list following the key.)
(The remarks in brackets refer only to the New Zealand species, and the number of species in each family is given only as a guide to the importance of the family and the possible ease with which specific determination may be made.)
Various families and genera of New Zealand amphipods have been revised recently by the author in the series. ‘Studies on the New Zealand Amphipodan Fauna’, in the Transactions of the Royal Society of New Zealand.
Shakespeare once sagely wrote, ‘What's in a name? That which we call a rose by any other name would smell as sweet,’ but this fine philosophical spirit is not always appreciated by students and amateur botanists faced with changes of name of familiar native plants. Most people who are interested enough in plants to want to recognise and name the different species realise that the system of Latin names is essential for accurate scientific study, but are discouraged by confusing name changes which they do not understand. Taxonomists, the botanists who classify and name plants, are often regarded as taking delight in ‘lumping’ and ‘splitting’ species and making unnecessary name changes, but this is a grossly unfair picture. The rules they have devised for naming plants aim above all at stabilising names and removing ambiguities and confusions, and even a superficial acquaintance with these rules will show what a difficult task taxonomists have to determine the one and one only correct name for every plant. Changes in established names are made reluctantly and only when absolutely necessary; to a large extent the botanists of the present must suffer in this way for the confusion and errors of the past when there were no rules. If the logical reasons behind the changes are understood they should not be resented.
Before name changes can be explained the structure of the names must be properly understood. The Latin names of the convenient natural units we term species are binomials, that is they are composed of the name of the genus or broad group to which the species belongs followed by the specific epithet which names the species and is peculiar to it. This is roughly comparable to putting one's surname first and Christian name second, and just as the same Christian names are used hundreds of times in different families so specific epithets can be used again and again in different genera, but names of genera can only be used once. The names of genera are nouns, and specific epithets are usually adjectives or possessive nouns. If they are adjectives, as most are, they must agree in gender with the name of the genus they are combined with. The name of the silver tree-fern, for instance, is Cyathea dealbata, Cyathea being the name of a genus of tree-ferns and
Until recently botanists used to distinguish specific epithets based on proper names by giving them a capital initial letter, such as Olearia Colensoi for the daisy tree named after Coprosma repens is the name of a native plant but it is correct to talk of a coprosma hedge.
A binomial plant name is not fully cited unless it is followed by the name of the authority, that is the botanist who gave the specific epithet. This is usually an abbreviation, as in Coprosma repens A.Rich. where A.Rich. stands for Achille Richard, an early French botanist who worked with New Zealand plants. A botanist who described numerous species of New Zealand plants was Sir
Though ‘species’ is in general the most useful category, categories of lower rank can be used to distinguish groups of less importance within a species. The most common infraspecific category is ‘variety’, abbreviated to ‘var.’, and varieties are named with epithets in the same way as species. Just as it is meaningless to quote a specific epithet without the name of the
prostrata, just as prostrate plants of Epilobium microphyllum have been named
The binomial system of nomenclature we are so familiar with today was first seriously used by the Swedish botanist Linnaeus in the middle of the eighteenth century, and was such an improvement on the haphazard systems previously used that it was quickly adopted and developed by other botanists. Though Linnaeus published his own nomenclatural principles there were no generally accepted rules at this stage, and as more and more plants were named confusion of names began to occur. On the whole botanists sensibly tried to avoid giving the same epithet to two different species in the one genus, and if they discovered that one plant had been given two names the earliest one was usually recognised as having the best claim, but distribution of literature was very slow by today's standards and it was not surprising that they constantly duplicated each other's names and named the same plant several times. At the first International Botanical Congress in 1867 an attempt was made to draw up an international code of rules for naming plants, but botanists disagreed in their opinions and for more than the next half-century different rules were applied in different countries. The differences were gradually ironed out and by the time of the fifth I.B.C. in 1930 agreement had been reached on all essential points, so that the third edition of the International Rules of Botanical Nomenclature then produced was truly internationally accepted and applied. The rules were revised by successive Congresses and the most recent edition is the ‘Paris Code’ adopted by the eighth I.B.C. at Paris in 1954 and published in 1956. Subsequent editions will be revised in their turn, for provision for modification is an important feature of the Code. Except in special cases the rules set out in the Code are retroactive, and are used to put past nomenclature in order as well as providing for future work.
In all matters of nomenclature, therefore, the current edition of the International Code of Botanical Nomenclature (as it is now titled) is the botanist's bible, and it is officially printed in English, German and French, and also translated into Spanish and Russian. Its precise phraseology and intricate provisions for every contingency are rather difficult for anyone but
The first Division of the Code contains the six Principles which are the basis of the system of botanical nomenclature, while the second and largest Division deals with the Rules by which the Principles are applied. The three Principles most relevant to this article are:
(The first article of the Rules explains that throughout the Code the word ‘taxon’, plural ‘taxa’, will be used to denote taxonomic groups of any rank. Full rules for taxa of all ranks are provided but only those referring to species and varieties will be discussed here.)
Types. The type system as put forward in Principle II is the essential link tying the system of nomenclature to the actual plants. Article 7 defines a nomenclatural type as that constituent element of a taxon to which the name of the taxon is permanently attached.
A note explains that this is not necessarily the most typical or representative element of a taxon. The type of Carmichaelia williamsii Kirk, for instance, is a specimen in the Kirk Herbarium at the Dominion Museum, Wellington, which was sent to Kirk by Bishop Williams. The type specimens of the many species described by Sir
A holotype (‘type’) is the one specimen or other element used by the author or designated by him as the nomenclatural type. For so long as a holotype is extant, it automatically fixes the application of the name concerned.
When no holotype was chosen by the author or it is lost or destroyed a substitute for it is chosen which may be either a lectotype or a neotype, a lectotype being chosen from the original material and a neotype from other material for so long as all the original material is missing. (Fuller notes on type nomenclature as applicable in Zoology have been given in Tuatara Vol. IV no. 2.) Type specimens are carefully preserved in the large herbaria of the world and are available for reference. Any taxonomist working with a group of species must study the type specimens to which the names are attached, or choose types if there are none, before he can come to any conclusion about the application of the names. Though every specimen placed in a certain species need not match the type in every detail, whatever limits are decided upon for the species must include the type.
When a species is divided into two or more varieties one of the varieties must include the type of the species and have this for its own type. It is known as the ‘type variety’ and must bear the same epithet as the species. This rule is stated in Article 25:
For nomenclatural purposes, a species or any taxon below the rank of species is regarded as the sum of its subordinate taxa if any. Valid publication of a subordinate taxon which does not include the nomenclatural type of the higher taxon automatically circumscribes a second taxon of the same rank which has as its nomenclatural type the type of the higher taxon …and bears the same epithet.
For example, Geranium traversii Hook.f. is a normally white-flowered species from the Chatham Islands which has as type specimen a white-flowered Travers specimen at Kew. When Cockayne described pink-flowered variants of this species as var. elegans he at the same time automatically created var. traversii containing all the plants matching the type in having white flowers. The type of var. traversii is the same Travers specimen which is the type of the whole species.
Choosing and Changing Names. Principles III and IV are the basis of the rules dealing with choice, retention and rejection of names. A large proportion of the name changes suffered by many of our plants are merely the replacement of previously used incorrect names with the correct one according to these rules. The limits of the taxa remain the same, and the changes are of name only in the strictest sense. Article 11 formally defines a correct name and states the rule of priority as it applies to species and taxa of lower ranks:
For any taxon below the rank of genus, the correct name is the combination of the earliest available legitimate epithet validly published in the same rank with the correct name of the genus, species, or taxon of lower rank to which it is assigned.
A ‘legitimate’ name is defined as one that is in accordance with the rules, while an ‘illegitimate’ name is contrary to the rules. What is termed ‘valid publication’ is clearly defined in another section and Article 12 states:
A name of a taxon has no status under this Code unless it is validly published.
That is, unless a name was published validly as described in the Code it cannot be considered in the system of priority at all or even classed as legitimate or illegitimate but is completely ignored. This is to ensure that names are published with proper descriptions in publications available to botanists so that there is no doubt what they are meant to apply to. The name of a taxon published without an accompanying description is known as a nomen nudum. No name published before 1753, the date of Linnaeus’ Species Plantarum, has any standing under the Code, this date having been fixed arbitrarily as the starting point for the system of priority.
A taxonomist in search of the correct name of a species therefore first finds all the validly published names which have been given to the species and, if possible, examines all the type specimens supporting the names to be sure that they really are all included within what he considers are the limits
merely because it is inappropriate or disagreeable, or because another is preferable or better known, or because it has lost its original meaning.
The earliest validly published epithet may be illegitimate for a number of reasons, most commonly
If it is a later homonym, that is if it duplicates a name previously and validly published for a taxon of the same rank based on a different type. Even if the earlier homonym is illegitimate, or is generally treated as a synonym on taxonomic grounds, the later homonym must be rejected. (Article 64.)
To find out if there is an earlier homonym for any name Index Kewensis must be consulted. This is a huge list of all the names of genera and species of flowering plants ever published which is brought up to date with a supplement every five years. There is no comparable list for ferns. Examples of names of New Zealand plants being abandoned because of the discovery that the epithet had been used before in the same genus are Senecio robustus Buchanan (1874) being renamed S. revolutus by Kirk because of S. robustus Sch.Bip. (1845), an Asian species, and, more recently, Epilobium parviflorum Simpson and Thomson (1943) being renamed E. pratense Simpson because of E. parviflorum Schreb. (1771). Accidental duplication of epithets like this is most likely to occur in genera such as Senecio and Epilobium which have a wide range in several continents. More unexpectedly a recently described New Zealand orchid Corybas saprophyticus Hatch (1952) had to be provided with a new name (C. cryptanthus) because of C. saprophyticus Schlecht (1924). With the literature now available mistakes of this kind should no longer occur. Provided the binomials were fully cited with their authorities, the previous uses of homonyms in literature should not be confusing, even when the identically named species come from the same region.
If the earliest epithet of a species is illegitimate (or has to be discarded for other reasons given in the rules) the later epithets (if any) must be considered in their turn until the earliest legitimate one is found. Names published after the earliest legitimate one (provided they were applied to exactly the same species) are automatically illegitimate because they were unnecessary. This is stated formally in Article 64: a name is illegitimate
If it was nomenclaturally superfluous when published, i.e. if the taxon to which it was applied, as circumscribed by its author, included the type of a name or epithet which ought to have been adopted under the rules.
Widely used names of many of our native plants are incorrect because they are illegitimate later synonyms, and name changes purely on the grounds of priority are common and regrettable but should become less frequent as the early literature relating to our flora is thoroughly examined.
Though it is incorrect to continue using the familiar synonyms now that they are known to be illegitimate, their use in past literature does not cause confusion, as in each case both the earlier and later names refer only to the one species. Thus though the pohutukawa has long been known as Metrosideros tomentosa A.Rich. (1832) its earliest and therefore correct name has been found to be
Authors often provided new illegitimate epithets instead of using the earliest when transferring a species from one genus to another. Previously it was considered allowable or even correct in these cases to provide a new epithet for the species in the new genus, but Article 55 of the present Code states:
When a species is transferred to another genus (or placed under another generic name for the same genus) without change of rank, the specific epithet, if legitimate, must be retained, or (if it has not been retained) must be reinstated, unless one of the following obstacles exists: (1) that the resulting binary name is a later homonym … (2) that there is available an earlier legitimate specific epithet.
The earliest legitimate epithets of many of our species were overlooked or ignored for many years because they were under different genera from those in which they are usually placed. Thus the heketara was named Olearia cunninghamii by Hooker in 1864 but it had already been named Brachyglottis rani by Cunningham in 1838 and the combination Olearia rani (A.Cunn.) Druce is the correct name.
An example from the genus Coprosma shows how proper application of the rules concerning priority and later homonyms to a nomenclatural tangle leads to three accepted names having to be discarded. The taupata was first named Coprosma repens by Richard in 1832. Hooker, not realising
There is no room in standard taxonomic works for such long nomen-clatural explanations as are given in the above paragraph. Instead taxonomists use a sort of shorthand which, if properly understood, conveys just as much information. The exact style varies but it is usual to list the name considered correct first, followed by the synonyms. The nomenclatural history of taupata can be summarised as set out below, for brevity the date of publication only being given instead of the full literature reference usually included:
Coprosma repens A.Rich. (1832) non Hook.f. (1844)
C. retusa Hook.f. (1844) non Petrie (1894)
C. baueri auct. non Endl. (1841) (quoted in error by Hooker as baueriana).
(The abbreviations ‘auct.’ (or ‘auctt.‘) and ‘auth.’, standing for auctores and authors, indicate that an epithet has been used in a particular sense by a number of authors.)
Though illegitimate names must be rejected, an epithet originally published as part of an illegitimate name may be made legitimate later in another combination. This is stated in a note to Article 72:
When a new epithet is required, an author may, if he wishes, adopt an epithet previously given to the taxon in an illegitimate name, if there is no obstacle to its employment in the new position or sense; the epithet in the resultant combination is treated as new.
For example, Kirk in 1877 named a small creeping native Veronica V. canescens, but this name was illegitimate as the combination V. canescens had been used previously three times in different senses. The species was renamed V. lilliputiana by Stearn in 1951 and lilliputiana remains the earliest legitimate epithet under the genus Veronica. However in 1944 Oliver had transferred the species to the genus Parahebe and the binomial P. canescens Oliver, treated as a new name dating from 1944, is legitimate though the combination P. canescens (Kirk) Oliver dating back to 1877
Parahebe is therefore canescens. If the epithet lilliputiana had been bestowed before 1944, however, it would have taken precedence in Parahebe also. A similar case with the events in the reverse order occurred in Metrosideros. Melaleuca lucida Forst.f. (1786), the earliest name of the southern rata, is an illegitimate later homonym of
Varietal epithets rarely have to be discarded because they are later homonyms; it is legitimate (though not recommended) to use the same epithet for varieties of different species in the same genus. It is also unusual for a variety of one species to be given two different epithets, However, application of Article 27 which states,
In the name of an infraspecific taxon which includes the nomenclatural type of the epithet of the next higher taxon, the epithet of this higher taxon must be repeated unaltered …without citation of an author's name. …
will cause the names of many varieties to be changed as this rule is comparatively recent. In the past frequently only the variety differing from the type would be named and described, the ‘type variety’ usually being described in the species description. If the type variety was described in parallel with the other varieties it was often given epithets such as ’ vera, typica, genuina’, which are not acceptable under the present Code. When Oliver divided Coprosma propinqua into two varieties he named one var.
Changes of Taxonomic Status. The examples of name changes that have been discussed so far are merely the substitution of correct names for incorrect ones according to the rules and must be accepted as absolute as long as the rules have been correctly interpreted. Name changes of another kind occur when two species are merged or a species is split into two, or when a variety is raised to specific rank or a species placed as a variety of another, or, more formally, when the limits of taxa or their relations to other taxa are altered. Frequently all the names involved are legitimate. Changes of this kind cannot be considered absolute as they depend to a certain extent on the personal opinion of different botanists and may be reversed more than once. The amateur botanist usually has little chance of deciding for himself which of two conflicting interpretations is nearer the truth and is best advised to follow the usage in the current standard Flora. The complex sets of alternative names in ferns give many good examples of this. Ferns are a world-wide yet comparatively small group which have
Blechnum procerum (Forst.f.) Swartz can also be considered merely a form of the African species
Although alteration of taxonomic status is the basis of these changes there are rules of nomenclature which must be followed when the changes are made. If, when a change of rank or of specific limits is made, the name selected is not the correct one in accordance with these rules, then a nomenclatural change will be necessary later in addition. The relevant rules, with explanatory examples, are as follows.
Artile 53: When a species is divided into two or more species, the specific epithet must be retained for one of them, or (if it has not been retained), must be reinstated. When a particular specimen was originally designated as the type, the specific epithet must be retained for the species including that specimen. When no type was designated, a type must be chosen….
In 1844 Hooker named a species of Coprosma from the Auckland Islands C. cuneata. In his work on the whole New Zealand flora in 1853 he enlarged his idea of the species to include slightly different North and South Island plants as well as the original Auckland Islands specimens, and this interpretation was followed in Cheeseman's Manual. In 1928 Oliver decided that this broad version of C. cuneata, or C. cuneata sens. lat., should be divided into two species, one the original Auckland Islands plant including the type which retained the epithet cuneata and became C. cuneata Hook.f. in the narrow sense (sens, strict.), and the other the North and South Island plant which he described as a new species C. pseudocuneata.
Article 57: When two or more taxa of the same rank are united, the oldest legitimate epithet is retained…. The author who first unites taxa bearing names or epithets of the same date has the right to choose one of them, and his choice must be followed.
For instance, if a future taxonomist decides once more that the New Zealand
C. repens A.Rich. (1832). Previously they were incorrectly united under the later name of the Norfolk Island species, C. baueri Endl. (1841).
Article 60: When the rank of a genus or infrageneric taxon is changed, the correct name or epithet is the earliest legitimate one available in the new rank. In no case does a name or epithet have priority outside its own rank.
Though it is thus not mandatory for authors to retain the existing epithet when changing the rank of a taxon, recommendations to Article 60 urge that this should be done whenever possible, and it very frequently is. When Hooker's two species Oreomyrrhis colensoi and O. ramosa were made varieties of O. andicola by Kirk he retained the same epithets and made them var. colensoi (Hook.f.) Kirk and var. ramosa (Hook.f.) Kirk, though he need not have done so. However, when their rank was changed back to that of species again, as mentioned above, there was no choice about using their original epithets in that rank. When O. andicola var. rigida Kirk, which was originally described as a variety, was raised to the rank of species parallel with the others, again the original epithet was retained to make it O. rigida (Kirk) Allan. Because the names have been kept the same these changes are not nearly so troublesome as they might have been. Some revisions resulting in changes of rank are not so easy to follow. The Spaniard Aciphylla colensoi Hook.f. is treated in Cheeseman's Manual as a wide-ranging species with two varieties, var. conspicua Kirk and var. maxima Kirk. The complex is now treated as three separate species. The old var. conspicua, which actually contained the type of the species and should have been var. colensoi, when treated as a species becomes A. colensoi sens. strict. Var. maxima Kirk has permissibly been renamed A. scott-thomsonii Ckn. et Allan and A. aurea Oliver is a newly described third species formerly included also in Cheeseman's wide treatment of A. colensoi. This old broad specific complex can be referred to as A. colensoi sens. lat. In some cases, especially when a variety is being raised to specific rank, a name change may be unavoidable because the varietal epithet would be a later homonym if used as a specific epithet. For instance, when Hooker wished to make his Viola cunninghamii var. gracilis a species he named it V. lyallii, undoubtedly because he knew there were several previous uses of the binomial V. gracilis.
Because of Article 57, when a taxonomist wishes to class two taxa previously regarded as separate species as two varieties of one species he must retain the older of the two specific epithets as the name of the combined species. When N. E. Brown decided that Wahlenbergia pygmaea Col. (1899) was only varietally distinct from W. albomarginata Hook.f. (1852), he placed the former as W. albomarginata var. pygmaea (Col.) N. E. Brown, at the same time automatically creating var. albomarginata. He could not have made W. albomarginata a variety of W. pygmaea.
Misapplication of Names. We have already dealt with changes of name caused either by replacement of incorrect names with correct ones or
Coprosma, found by looking at the type specimen that the species commonly known as C. depressa Col. ex Hook.f. was quite different from the one originally described under that name which was passing under the later name C. ramulosa Petrie. Colenso's species therefore had two names while the one commonly known as depressa really had none. To right this Oliver discarded C. ramulosa as an illegitimate later synonym of C. depressa and named the unnamed species C. cheesemanii, but the confusion as to what an author means when referring to ‘C. depressa Col. ex Hook.f.’ is less easily cleared up. A worse example of this sort of tangle occurred in the genus Rubus. Rubus australis. We shall call this species (a). Cunningham in 1830 described two more species (b) and (c) and named them respectively
Names of Genera. The rules concerning the names of genera have not been discussed but many of them are similar to those governing specific epithets, with obvious exceptions following on the difference in rank of the two categories. Most of the changes made in generic names in the New Zealand flora are the result of differing opinions of generic limits and, like the alternative names and changes of rank of species and varieties mentioned earlier, are not necessarily to be accepted. The kowhai is usually placed in section Edwardsia of the genus Sophora, but some botanists prefer to treat Edwardsia as an independent genus. The group of species originally described under the genus Myrsine have been regarded by other authors as
Suttonia and Rapanea. Again the ferns provide numerous examples. The filmy ferns placed in Cheeseman's Manual under the genus Hymenophyllum can be split up into groups and placed under a number of different genera such as Mecodium, Meringium, etc., leaving only a few in Hymenophyllum sens. strict. The common polypody P. diversifolium has at different times been placed under the genera Polypodium, Microsorium and Phymatodes. Changes of generic names which are simply corrections of nomenclature are rare, though in the orchids Corybas Salisb. (1805) has replaced Corysanthes R.Br. (1810) purely on the grounds of priority. Stability of generic names is aided by a provision of the Code which allows generic names to be permanently conserved against earlier homonyms or legitimate synonyms if it can be shown that changing them would upset well-established and very widely-used names. For instance, when the monotypic New Zealand genus Shawia, founded in 1776 to contain the akiraho S. paniculata, was merged with the later-published but much larger genus Olearia (1802) the name Olearia was conserved against Shawia (for as long as the two were united) because it had been widely used for a large number of species. Other conserved generic names (or nomina conservanda) in the New Zealand flora are Nertera, Pterostylis, Wahlenbergia, Parsonsia and Persoonia. Specific epithets cannot be conserved in this way.