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Tuatara: Volume 27, Issue 2, December 1984

Notes on Some Anthocerotae of New Zealand (4)

page 105

Notes on Some Anthocerotae of New Zealand (4)

Taxonomy, morphology and distribution of Megaceros leptohymenius (Hook. f. & Tayl.) Steph., M. denticulatus (Lehm.) Steph. M. arachnoideus (Steph.) Steph. and M. flagellaris (Mitt.) Steph. are reported. Notes are given on other species recorded for New Zealand. Anthoceros coriaceus Steph. is transferred to Phaeoceros comb.n.

Keywords: Anthocerotae, Megaceros leptohymenius, Megaceros denticulatus, Megaceros arachnoideus, Megaceros flagellaris, Phaeoceros coriaceus.

The Genus Megaceros

Introductory remarks and key to the species.

Since all the species of Megaceros which occur in New Zealand are highly variable in their morphology, determination at species level is often difficult and particularly so in the case of incomplete herbarium specimens. Sometimes, too, different species of Anthocerotae grow intermixed.

The 4 species of Megaceros described below may be identified by the following key.
1. Spherical face of spore papillateM. leptohymenius.
Spherical face of spore with verrucose projections2.
2. Thallus dioecious, large and rigid; margin usually denticulateM. denticulatus.
Thallus monoecious, thin; margin entire, crenulate or fimbriate3.
3. Upper surface of thallus with branched filamentsM. arachnoideus
Upper surface of thallus smoothM. flagellaris

(i) Megaceros leptohymenius (Hook. f. & Tayl.) Steph.

(a) Distribution

This species is widespread in New Zealand forests growing on the ground or on the bark of fallen trees. Frequently it has been confused with other members of the Anthocerotae. It is apparently endemic.

(b) References and Sources of Material

The species was named Monoclea leptohymenia by Hooker and Taylor (1844). Later Taylor (1846) transferred it to Dendroceros and still later Stephani (1916) transferred it to Megaceros. The type packet at the British Museum was annotated by Proskauer as containing a mixture of M. leptohymenius and M. denticulatus. A specimen of M. leptohymenius, accompanied by notes made by Stephani (sheet 7548) was available for examination by courtesy of the Curator of the Stephani Herbarium, Geneva. Specimens collected by Petrie and named by Stephani are in the National Museum, Botany Division DSIR and the Hodgson collection (MPN 18564). One of these (H 14) was found to be M. leptohymenius interlayered with Monoclea forsteri. In the William Mitten Herbarium at the New York Botanical Garden is a specimen (Colenso 2551) in the Phaeoceros laevis folder I consider to be M. leptohymenius, and also a New Zealand specimen on the same sheet tentatively annotated as M. leptohymenius by Proskauer and yet another collected at Auckland by Lyall and already annotated by Proskauer as M. leptohymenius.

Fresh material was obtained from Kaimanawa Forest Park, Tararua Range, Wellington Botanic Gardens, Abel Tasman National Park, Copland Valley, Westland and Stewart Island. It was maintained in culture at Massey University for up to three years.

page 106
Fig. 1 Plant of M. leptohymenius. Photo by L. Maiden.

Fig. 1 Plant of M. leptohymenius. Photo by L. Maiden.

(c) Morphology of the Gametophyte

There is a juvenile thallus which forks repeatedly giving branches of a rather uniform width of 0.1-0.2mm which spread out horizontally at a wide angle (Figs. 2 & 3). The margin is entire or almost so. In contrast the mature thallus is much larger with a horizontal spread of up to 5cm (Fig. 1). It is firm and rather thin, olive-green in colour and branched at a wide angle. The branches are ligulate, 3-10mm broad and up to 3cm long, with an irregularly crenulate margin. It may be supported by other bryophytes or anchored by rhizoids.

Plants may be monoecious but often are dioecious. In male-only plants the branches tend to be about 10mm broad and 6mm long. The antheridial cavities may be seriated in one or two rows, or irregularly scattered. Each contains a single large conspicuous antheridium with a spherical to oval body, up to 0.3mm long and 0.24-0.3mm broad, attached by a short stalk. Branches with archegonia tend to be longer. Since archegonia form singly behind the apex over a long period, there may be old unfertilised ones more or less seriated and widely spaced over a considerable length of the thallus. Later there may be sporophytes.

(d) Anatomy of the Thallus

The juvenile thallus is up to 4 cells deep medianly and 3 cells deep at the margin. There may be only one large chloroplast per cell but more commonly it is constricted or dumb-bell shaped, or in older parts may have divided into two. The mature thallus is about 0.3mm deep medianly and gradually becomes thinner to about 0.1mm near the margin. Above and below are small cells containing either one or two large rounded chloroplasts or occasionally an elongated or constricted one. The larger central cells usually contain two, but occasionally four or even six, less conspicuous chloroplasts. Pores are present in both the upper and lower surface and scattered cavities contain Nostoc.

page 107
Fig. 2 Group of juvenile thalli from the surface of an old disintegrated thallus. Photo by B. Campbell. Fig. 3 A single juvenile thallus. Photo by B. Campbell.

Fig. 2 Group of juvenile thalli from the surface of an old disintegrated thallus. Photo by B. Campbell.
Fig. 3 A single juvenile thallus. Photo by B. Campbell.

(e) Morphology of the Sporophyte

The slender capsule, 3-4cm long, is surrounded at the base by a thin, fleshy cylindrical involucre 3-10mm high. The capsule wall lacks stomata. It opens on one side below the apex by a lengthwise slit which broadens somewhat. It may remain in this condition until the spores are shed or later, due to curling and twisting movements in dry air, the capsule may partially split on both sides or the first slit may extend to the apex. The spores tend to hold together for a considerable time and are only slowly freed. When shed they are bright green due to a single large chloroplast, but become straw-coloured in herbarium specimens. They have a diameter of 34-36 microns. The triradiate face at a magnification of up to x1000 appears practically smooth but at x6000 a low surface meshwork is visible; the outer face has numerous papillate projections about 1.3 microns high (Fig. 4). The monospiral elaters, made of 2-3 cells, are 0.1-0.27mm long.

Comments

1.

Particularly in autumn numerous new thalli arise on the edges and at times on the surface of old ones, appearing at first as finger-like projections which later fork repeatedly (Fig. 3). The old thalli then tend to disintegrate and groups of juvenile ones lie entangled in its remains and in any moss protonemata or rhizoids in the vicinity (Fig. 2). A rather similar type of regeneration occasionally takes place from the margin of the thallus of Phaeoceros laevis and can be distinguished only by the lack of repeated, regular forking at a wide angle and the form and number of the chloroplasts. Regenerates from other species of Megaceros at some stages of their development are also difficult to distinguish (see below).

2.

Spores of Megaceros leptohymenius resemble those of Phaeoceros laevis but the presence in the former species of true elaters with helical thickening enables certain identification.

page 108
Fig. 4 Spore of M. leptohymenius left: triradiate face. Right: outer face. Scanning electron micrographs by G. Walker.

Fig. 4 Spore of M. leptohymenius left: triradiate face. Right: outer face. Scanning electron micrographs by G. Walker.

3.

3. The presence, even in older parts of the thallus, of cells with only one chloroplast is unusual in a Megaceros.

4.

4. A note on Anthoceros nostocoides Pears. This species was described and illustrated by Pearson (1923) from specimens which W. A. Setchell had collected at Pipiriki in 1904. As they were sterile, Pearson could not determine whether they belonged to Anthoceros or Megaceros. By courtesy of the University of California (Berkeley) the type U.C. 213714 was available for examination. Already it had been annotated by Proskauer who noted that “the shape and structure of the thallus and adhering diatom flora suggest this to be a growth form grown under constant trickle of water or at least under very moist conditions. Can be identified by reference to original locality only”.

When I visited Pipiriki on December 26, 1979, I found Megaceros leptohymenius growing on seepage banks alongside the track leading down from the site of the accommodation house to the landing jetty on the Wanganui River. The plants were sterile but some have been kept growing in culture and compared with M. leptohymenius from other localities. Since A. nostocoides in my opinion is a sterile form of M. leptohymenius, I consider that the name must be rejected.

(ii) Megaceros denticulatus (Lehm.) Steph.

(a) Distribution

This species is found on the floor of forests or shrubbery chiefly in the wetter and cooler southern regions and mountains of New Zealand, south of Mt Egmont, and also in Tasmania and south-eastern mainland Australia.

(b) References and Sources of Material

The species was described by Lehmann (1857) under the name Anthoceros denticulatus and transferred to Megaceros by Stephani (1916). A named specimen from New Zealand along with a description by Stephani (sheet 7545) was available for examination by courtesy of the curator of the Stephani Herbarium, Geneva. Another named New Zealand specimen, ex herbarium of Angstrom, is in the Hodgson collection (MPN 18565) and still others from both New Zealand and Australia are at the British Museum. Fresh material, obtained from Stewart Island and Mt Egmont, was observed in culture over 3 years.

page 109
Fig. 5 Part of a vegetative plant of Megaceros denticulatus. Photo by L. Maiden.

Fig. 5 Part of a vegetative plant of Megaceros denticulatus. Photo by L. Maiden.

(c) Morphology of the Gametophyte

The firm rigid olive-green thallus, up to 6cm long and 4cm broad, growing more or less horizontally and branching irregularly, resembles a large Aneura (Fig. 5). It is anchored to soil and rock by short rhizoids. Branches are up to 1cm wide. They have an irregularly lobed margin which, under a dissecting microscope, normally appears denticulate due to irregular, simple or forked, projections which typically are 2-8 cells high and 2-3 (or more) cells wide at the base, but sometimes these are little evident.

The plants studied were found to be dioecious although according to Stephani (1916) the species is monoecious. Antheridial cavities appear in groups behind the apices of male plants in September. Each cavity contains a single antheridium with a club-shaped head, up to 290 microns long and 220 microns wide, and a stalk 40-50 microns long. On female thalli archegonia appear in September in groups immediately posterior to each apex and may be so closely crowded as to touch one another. Later there may be sporophytes.

(d) Anatomy of the Thallus
As seen in a transverse section the thallus is 0.7-1.3mm deep medianly but gradually becomes thinner to about .08mm near the margin. The small, upper epidermal cells are .03–.05mm deep with firm and at times somewhat thickened walls. In young parts each cell has one large chloroplast which is very variable in shape but is usually constricted or dumb-bell shaped (Fig. 6), in older parts there may be up to 4 rounded chloroplasts but sometimes an elongated or V shaped one. The lower epidermal cells also are small, being .01–.03mm deep; each has a single chloroplast except when rhizoidal. The central cells are larger, up to .12mm deep with thin but firm walls which often appear pitted due to prominent primary pit fields (Fig. 7) and page 110
Fig. 6 (left) Some chloroplast shapes a. rounded b. elongated c. constricted d. dumbbell shaped. Fig. 7 (right) Single cell of the thallus showing prominent primary pit-fields (dotted).

Fig. 6 (left) Some chloroplast shapes a. rounded b. elongated c. constricted d. dumbbell shaped.
Fig. 7 (right) Single cell of the thallus showing prominent primary pit-fields (dotted).

Fig. 8 Plant with sporophytes. On the left 2 sporophytes share a common involucre. Photo by L. Maiden.

Fig. 8 Plant with sporophytes. On the left 2 sporophytes share a common involucre. Photo by L. Maiden.

at times have small trigones at the angles. Each cell contains 2-8 discshaped chloroplasts. Pores are present, usually on the underside of the thallus, and Nostoc colonies may bulge from the lower surface.
(e) Morphology of the Sporophyte

The capsule, up to 2cm long, is surrounded at the base by a firm, conical involucre 2mm high (Fig. 8). It opens by 2 longitudinal slits, at first located some distance below the apex, but later these gradually extend to the apex as well as downwards.

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Fig. 9 Spore of M. denticulatus left: triradiate face. Right: outer face. Scanning electron micrographs by G. Walker.

Fig. 9 Spore of M. denticulatus left: triradiate face. Right: outer face. Scanning electron micrographs by G. Walker.

The spores, of diameter 26-34 microns, are green due to the dark green colour of the chloroplast. The outer face is verrucose with irregular knob-like thickenings as well as papillate projections; the triradiate face has papillate projections only (Fig. 9). The elaters, 105-275 microns long, are made of 2-3 cells and have a helical band of thickening.

Comments

1.

Regeneration takes place from new growths arising at the margin and from the lower surface of the thallus, particularly after the shedding of the spores. These detach readily although normally the old thallus does not disintegrate immediately.

2.

Although, in the dim light of the forest, vegetative plants of M. denticulatus are easily confused with Aneura alterniloba (Hook. f. & Tayl.) Tayl. which may also have a denticulate margin, the latter can be distinguished under a microscope by the oil-bodies and numerous small chloroplasts in the cells, and by the lack of blue-green algal colonies in the thallus.

(iii) Megaceros arachnoideus (Steph.) Steph.

(a) Distribution

This species is widespread in New Zealand forests and wet heathlands growing as irregular, greyish-green to olive green flat mats, up to 10cm in diameter, either on soil, on decaying bark and roots, or on other bryophytes. It is very abundant in Nothofagus forest on free-draining banks bordering the Waikareiti Track in Urewera National Park.

(b) Reference and Sources of Material
The species was first named Anthoceros arachnoideus by Stephani (1892), from specimens collected by Colenso in New Zealand, and later transferred to Megaceros (Stephani, 1916). By courtesy of the Curator of the Stephani Herbarium at Geneva a type specimen, as well as Colenso 1035 and sheet 7549 was available for inspection. On the latter is a dried specimen, a drawing of the thallus in transverse section, and notes written by Stephani. Isotypes, Colenso a 1260, are in the Hodgson collection (MPN 18589), in the National Museum, Wellington and in the British Museum. Other material was collected by Goebel during his visit to New Zealand in the summer of 1898-9. He first mentioned the species briefly page 112
Fig. 10 Plant of M. arachnoideus. Photo by L. Maiden.

Fig. 10 Plant of M. arachnoideus. Photo by L. Maiden.

(Goebel, 1905) and later published a figure showing the outgrowths on the upper surface of the thallus along with a detailed account of their structure and function (Goebel, 1906). Still other specimens which have been identified by E. A. Hodgson are in the Hodgson collection and Khanna (1944) gave a brief description of plants supplied to him by E. A. Hodgson. Fresh specimens were obtained from Urewera National Park (collected by A. Green), from Stewart Island (collected by H. D. Wilson, and C. Meurk) from Nelson (collected by J. Abraham) and from the Ruahine Range, Pirongia Mountain, Tiritea Valley (near Palmerston North), and Fiordland. They were grown in culture for 3 years.
(c) Morphology of the Gametophyte

The broadly spreading, sometimes rather fleshy and sometimes very thin thallus, forks repeatedly and becomes irregularly lobed (Fig. 10). The ultimate branches, broadly obovate and up to 1 cm wide, often lie free of the substratum, whereas older parts of the thallus are attached by numerous rhizoids. The upper surface, when moistened, is yellow-green to olive-green in colour but, when not wetted, young parts often show a characteristic hyaline or whitish encrustation made from lamellae and crests or from clusters of branched filaments whose enlarged terminal cells are pale or colourless (Fig. 11 and 12). Further back these outgrowths tend to disappear and at times even near the apex they are not obvious. The margin at a magnification of ×5 appears crenate but at ×100 is highly irregular due to numerous multicellular protuberances similar to those on the upper surface. However, in plants of the high rainfall area of Fiordland and of dripping rock-faces elsewhere these are present only near the apex and sparsely even there.

Plants are monoecious. The antheridial cavities tend to be arranged in compact groups of 3 to 10 or more and are often located near the margin of the thallus. Each cavity contains one antheridium with a spherical head 0.19-0.25mm in diameter and a stalk 3-6 tiers of cells high. The numerous page 113
Fig. 11 (left) Transverse section of the thallus showing surface projections. Fig. 12 (right) A single projection.

Fig. 11 (left) Transverse section of the thallus showing surface projections.
Fig. 12 (right) A single projection.

archegonia also tend to be in groups, either on the same branch and adjacent to, or intermixed with, the antheridia or on a separate branch. Sporophytes are normally numerous.
(d) Anatomy of the Thallus

The thallus as seen in a transverse section is usually 0.2-0.4mm deep medianly and 0.1mm towards the margin, but in the vicinity of the sporophyte it may be up to 1.3mm deep. Above and below are small cells, 13-30 microns deep; the upper ones have either one large chloroplast, which may be disc-shaped, elongated, constricted or dumb-bell shaped, or 2-4 smaller disc-shaped chloroplasts; the lowermost usually have two disc-shaped chloroplasts or occasionally an elongated or constricted one. The interior cells gradually become larger towards the centre of the thallus where they are 40-60(−145) microns deep. They have either 2-4(−8) rounded chloroplasts which tend to be pale in colour, or no discernible ones. On the lateral walls large primary pit fields, which are particularly well-defined near the base of a sporophyte, give a reticulate appearance. On the margin of the thallus and sometimes on the upper surface there are protuberances; on the lower surface in the posterior region there are rhizoids; while on both surfaces there are pores leading into cavities which later may become occupied by the blue-green alga Nostoc. At times the algal colonies become so large that they protrude from the thallus.

The surface and marginal filamentous outgrowths were examined in detail by Goebel (1906). He found that the hyaline appearance is due to a gradual reduction in the size of the chloroplasts from the base upwards until in the larger terminal cells of both main and lateral branches these are often no longer discernible. The arrangement of the filaments is such as to produce a spongy construction which is especially marked where they are crowded at points of forking of the thallus.

(e) Morphology of the Sporophyte

The involucre surrounding the base of the sporophyte is 4-11mm high. Its green fleshy base is up to 2mm wide but towards the apex it gradually page 114 narrows to a width of 0.5-1 .0mm and here may become brown and papery. On its surface are protuberances similar to those on the thallus. The slender green capsule is 0.5mm wide and normally 4-6cm high but occasionally no more than 2cm. It opens along lines of thin-walled cells, at first by one and later by two longitudinal slits, into valves which gradually turn brown and undergo slight twisting, but remain joined at the apex except in very old capsules (Fig. 13). The central columella is very slender. The spores have a large chloroplast and appear green when the capsule opens but on drying become much paler. They have a maximum diameter of 32-37 microns and are highly irregular in shape. The inner face has a papillate surface and an indistinct triradiate marking; the outer face is not only papillate but verrucose, with rounded protuberances 2.6 microns high, up to 10 appearing in profile in an optical section (Fig. 14). The elaters, up to 370 microns long and 5 microns wide, are usually made of more than one cell and are colourless apart from a single, straw-coloured band 0.8 microns wide.

Comments

1.
After the spores are shed thalli which have borne sporophytes tend to die off but regeneration occurs from the margin and at times from the surface of the old thallus. Marginal regenerates also arise copiously at times on other thalli. At some stages of their development the new thalli are difficult
Fig. 13 Plant showing a dehisced sporophyte. Photo by L. Maiden.

Fig. 13 Plant showing a dehisced sporophyte. Photo by L. Maiden.

page 115
Fig. 14 Spore of M. arachnoideus left: triradiate face. Right: outer face. Scanning electron micrographs by G. Walker.

Fig. 14 Spore of M. arachnoideus left: triradiate face. Right: outer face. Scanning electron micrographs by G. Walker.

to distinguish from those of M. leptohymenius but they tend to remain attached to the old thallus for a longer period, to develop rhizoids early and to show more rapid broadening of the branches along with arrangement in a fan shape.
2.

Goebel (1906) interpreted the outgrowths as a whole as functioning in water retention and the hyaline terminal cells as functioning in water absorption. He related this to the lack of rhizoids in the anterior part of the thallus.

(iv) Megaceros flagellaris (Mitt.) Steph.

(a) Distribution

In New Zealand as elsewhere in its range this species is often found on wet rocks alongside streams and on decaying logs in shaded valleys. Rarely it is epiphyllous on fern fronds (Welt, H 8741). It occurs also, as demonstrated by Hasegawa (1983), in India, Thailand and Japan as well as being widely distributed through the Pacific Islands.

(b) References and sources of material.

From a specimen collected by Rev. T. Powell in Samoa Mitten (1871) first described the species as Anthoceros flagellaris. Later Stephani (1916) transferred it to Megaceros. Sheet 7525 of Stephani's unpublished Icones was available for inspection. It contains a pressed specimen from Fiji and notes made by Stephani. Hasegawa (1983) gave a more detailed description and noted the great plasticity that he had observed while studying a wide range of specimens. He also provides a valuable list of the many synonyms which in the past have been applied to M. flagellaris. Previously it has not been recognised in New Zealand. Fresh material was obtained from the Akatarawa Valley, Wellington (collected by B. V. Sneddon) and from the Kahuterawa Valley near Palmerston North.

(c) Morphology of the gametophyte
The thallus is rather firm with a smooth upper surface and when fresh is pale green, bright green or olive green in colour. Up to 5 cm long, it usually lies flat on the ground (Fig. 15) and is loosely attached by scattered short rhizoids arising from the lower surface. Repeated forking produces widely radiating branches 3-8mm wide, which may be broad with widened apices page 116
Fig. 15 Part of a colony of M. flagellaris

Fig. 15 Part of a colony of M. flagellaris

or linear and somewhat pinnately lobed. Their margin is highly variable, ranging from entire to crenulate, irregularly lobed or laciniate.

Plants are monoecious. Antheridial cavities, each containing a single antheridium, 0.15-0.25mm in diameter, lie closely aggregated near the margin or, less commonly, scattered in the central region of the thallus. Numerous archegonia occur intermixed with the antheridial cavities or on separate branches and later there are, as a rule, many sporophytes.

(d) Anatomy of the thallus

The thallus as seen in sections is 6-11 cells deep in the broad median region but near the margin it is only 1-4 cells deep. All the cells are thin-walled but the surface ones are 13-16 microns deep while those of the interior are much larger being up to 87 microns deep and also considerably elongated in a lengthwise direction. The number of chloroplasts in the surface cells ranges from one near the apex to 4 or more in mature portions of the thallus while in the interior cells the number is also variable, normally more than 2 and at times as many as 14. Pores are present near the apex on the ventral surface and lead into cavities which may become occupied by Nostoc and produce bulges of the under surface.

(e) Morphology of the sporophyte.

The slender capsule, up to 8 cm long, is surrounded at the base by a smooth involucre, 0.5-1.3 cm high. It opens at first by a single slit below the apex and later usually by 2 which may extend right to the tip. The spores, of diameter 26-36 microns, are more or less globose but irregular in shape. The inner face in New Zealand specimens is papillate with short papillae and shows a weak triradiate marking. The spherical face is verrucose with a few warty projections amongst smooth papillae (Fig. 16). The elaters, up to 400 microns long, are usually made of more than one cell and have a single helical band.

page 117
Fig. 16 Spore of M. flagellaris. left: triradiate face. Right: outer face. Scanning electron micrographs by G. Walker.

Fig. 16 Spore of M. flagellaris. left: triradiate face. Right: outer face. Scanning electron micrographs by G. Walker.

Comments

1.

A colony on a wet roadside bank at Rangiwahia, Ruahine Range, frequently showed geminate involucres and the capsules were short.

2.

Multiplication takes place freely by adventitious development of new thalli from the margin or surface of older ones. The regenerative process and particularly the dedifferentiation of multiplastid cells was studied in detail by Burr (1969).

3.

In some specimens from places outside New Zealand the warty projections on the spore coat are poorly developed or even absent, resulting in the spores being described as papillate (Hasegawa, 1983).

Notes on Other Species Which are Listed for New
Zealand by Hamlin (1972)

Megaceros aneuraeformis Steph.

According to Stephani (1916) this is a plant of Brazil. Thus it is unlikely to occur in New Zealand although listed by Hamlin (1942) under the name Anthoceros aneuraeformis. However, see notes under Megaceros novae-zelandiae.

Megaceros grandis (Angstr.) Steph.

This species was first named Anthoceros grandis by Angstrom (1873) from a plant collected in 1852 by N. J. Anderson in Tahiti, and later transferred to Megaceros by Stephani (1916). By courtesy of the Curator of the Stephani Herbarium, Geneva the type (G 21931) was available for examination. Already in 1982 it was annotated by J. Hasegawa as being synonymous with M. flagellaris (Mitt.) Steph. Sheet 7531 of Stephani's Icones, containing a pressed specimen and a description was also kindly made available for examination.

The recording of the presence of M. grandis in New Zealand is based on identification, description and figures provided by Khanna (1944) from a specimen H 511 sent to him by E. A. Hodgson and now located in National Museum, Wellington. It was collected by K. W. Allison on 17-3-1934 on Mt Tauhara near Taupo about 3000 feet. The habitat is given as “stream side on bog in bush”. A duplicate is at Botany Division. Khanna's description (1944) fits M. flagellaris as does the specimen, although the page 118 latter is now difficult to determine as it has only a few very old capsules and groups of old antheridial cavities. In addition there is in the Hodgson collection a packet of Megaceros collected by H. L. Hodgson in January 1940 from Mt Tauhara (MPN 18598). The capsules are mostly young but a few mature spores were found to be verrucose as in M. flagellaris In my opinion the specimens from Mt Tauhara represent M. flagellaris from a wet shady situation which is subject to flooding, as evidenced by the silt and diatoms on the plants.

Anthoceros granulatus Col.

This was collected by W. Colenso in November 1884 from “rotten logs, growing with Aneura crispa, shady bases of cliffs, River Mangatawhainui, near Norsewood, county of Waipawa.” I have been unable to locate the type but the description of a plant “covered with masses of fine sparkling granules, as if frosted (or like soredia in some species of Parmelia)” (Colenso, 1886) sulrey applies to Megaceros arachnoideus. The same name, Anthoceros granulatus, was given earlier by Gottsche, in 1863, to a plant from Mexico with black, echinate spores (Stephani, 1916).

Megaceros hodgsoniae Khanna

This species was described and illustrated by Khanna (1944) from a specimen forwarded to him by E. A. Hodgson, who had collected it on papa rock (a silt-stone) in a creek in deep shade at Kiwi, Wairoa in April, 1935. The type, E. A. Hodgson 771, is now located at the National Museum, Wellington. According to Khanna the distinguishing features are the frequent geminate involucres and the short capsules.

However, my examination of the type showed that it corresponded with the form adopted by M. flagellaris in wet, shady localities. Elsewhere geminate involucres and short capsules have been found in M. flagellaris in such situations.

Megaceros novae-zelandiae Steph.

This species was described by Stephani (1916) from material collected in New Zealand. It was at first called Anthoceros aneuraeformis (Stephani, 1893) and later Megaceros aneuraeformis, under which name specimens are filed in the Stephani Herbarium, Geneva.

By courtesy of the Curator of the Stephani Herbarium sheet 7543 of Stephani's unpublished drawings was available for examination. The label reads “Anthoceros novae-zelandiae (olim aneuraeformis).” On the sheet are an outline drawing of the vegetative thallus and two descriptions. One description refers to a plant, regarded as the type (Bonner, 1962), which was collected by Helms in Auckland in 1888. The other description, which is closely followed by that of Megaceros novae-zelandiae (Stephani, 1916), is drawn up from a plant collected by W. N. Beckett in 1906 on Mt. Winterslow (Canterbury) on wet places on the ground and now filed as Megaceros aneuraeformis, Bryotheca E. Levier 5371, in the Stephani Herbarium. A duplicate specimen (Beckett 455), determined by Stephani as Anthoceros anueuraeformis and located in the Herbarium of Botany Division, Christchurch, was kindly made available by the Curator.

Although a detailed examination was not possible, this specimen was found to differ in several respects from Stephani's descriptions. The spores correspond with those of Megaceros leptohymenius, to which species I consider the plant belongs. However, specimens in the Hodgson collection (MPN 18596 and 18597) identified as Megaceros novae-zelandiae by E. A. Hodgson came from very wet areas; they are monoecious and have capsules and verrucose spores as in M. flagellaris.

page 119

Megaceros pallens (Steph.) Steph.

This was first described as Anthoceros pallens (Stephani, 1892) from New Zealand material sent by Colenso; and later transferred to Megaceros (Stephani, 1916). Sheet 7549 of Stephani's Icones containing a pressed specimen and a description was available for examination by courtesy of the Curator of the Stephani Herbarium, Geneva. The later description (Stephani, 1916) was also consulted.

Differences between this species and M. arachnoideus, on the basis of Stephani's descriptions, are the small size (27 microns) and weaker ornamentation of the spores. This could be due to the immature state of such spores as remained in the capsule. The vegetative features, particularly the crested thallus with a laciniate margin, strongly suggest that there is not sufficient distinction from M. arachnoideus to warrant the erection of a separate species.

Megaceros zotovii Khanna.

This species was described by Khanna (1944) from material collected by V. D. Zotov 26/11/1933 at Akatarawa Saddle, Tararua Mountains and sent to him by E. A. Hodgson. From a study of the type (E. A. Hodgson 10533), which is now located at the National Museum, Wellington, together with the description and figures published by Khanna (1944) my conclusion is that it represents M. flagellaris. It corresponds in the monoecious condition, and in the form of the capsule, involucre and spores.

Megaceros pellucidus (Col.) Hodgs.

This was first named Anthoceros pellucidus by Colenso (1885) and transferred to Megaceros by Hodgson (1972). The type specimen, Colenso a 1362, was available from the National Museum, Wellington also an isotype in the Hodgson Herbarium (MPN 18592). The type was collected by W. Colenso in 1882-4 “on rotten logs in dark wet woods, spreading over and adhering to other small Hepaticae, mosses, dead twigs, etc., near Norsewood, county of Waipawa”.

An examination of the specimens showed that they have a smooth surface and are monoecious. There are old antheridial cavities, and a few capsules containing elaters and verrucose spores. However, the narrow fronds which are mentioned in the description (Colenso, 1885) belong to Riccardia and the so-called gemmae represent cavities containing Nostoc. The species was not recognised by Stephani (1916) for an incomplete specimen sent by Colenso and now at the British Museum bears his comment “sterile; impossible to determine”. However, it is now considered to be M. flagellaris.

Megaceros membranaceus (Col.) Hodgs.

This was first named Anthoceros membranaceus by Colenso (1886) and transferred to Megaceros by Hodgson (1972). The type is at the National Museum, Wellington (H 7822) and an isotype is in the Hodgson collection (MPN 18593). These were collected by Colenso in 1884 “on logs in wet dark woods, near Norsewood, county of Waipawa, growing underneath large Aneura etc.” A specimen collected by Colenso and determined by Mitten in 1886 was also examined by courtesy of the British Museum. It is considered that the specimens belong to M. flagellaris.

A note on Phaeoceros

Grolle (1983) has carefully examined the question of the usage of the name Phaeoceros. He concludes that, according to the Rules of Botanical Nomenclature and despite the recently expressed opinions of Schuster and page 120 Schljakov, this is the correct name for the yellow-spored species, while Anthoceros is correct for the black-spored species. All of these species were combined under the name Anthoceros in the earlier papers of this series.

However in the present paper the name Phaeoceros laevis (L.) Prosk. is used instead of Anthoceros laevis. Also Phaeoceros coriaceus (Steph.) Campb. comb. n. will replace Anthoceros coriaceus Steph. as used previously (Campbell, 1982).

Acknowledgments

The writer is indebted to the curators of the herbaria at the British Museum, the New York Botanical Garden, the Stephani Herbarium Geneva, the University of California (Berkeley), Botany Division, Christchurch and the National Museum, Wellington, for the opportunity to study herbarium specimens; to D. Havell, D. Pearce, B. Macmillan. A. Ratkowsky, B. V. Sneddon and H. Wilson for providing fresh material; and to J. Hasegawa for helpful information about M. flagellaris.

References

Angstrom, J. 1873: Forteckning och beskrifning ofver Mossor, samlade af Professor N. J. Andersson under Fregatten Eugenies… 1851-53. Kongliga Vetenskaps-Akademiens Fordhandlingar 30: 139.

Bonner, C. E. B. 1962: Index hepaticarum Part 2 : 1-320 J. Cramer, Weinheim.

Burr, F. A. 1969: Reduction in chloroplast number during gametophyte regeneration in Megaceros flagellaris. The Bryologist 72:200-209.

Campbell, E. O. 1982: Notes on some Anthocerotae of New Zealand (2) Tuatara 25:65-70.

Colenso, W. 1885: A description of some newly discovered and rare indigenous plants: being a further contribution towards the making known the botany of New Zealand. Transactions New Zealand Institute 17: 237-265.

Colenso, W. 1886: A description of some newly-discovered cryptogamic plants, being a further contribution towards making known the botany of New Zealand. Transactions New Zealand Institute 18: 219-255.

Goebel, K. 1905: Organography of Plants. Part 2. Special Organography. English edition. Oxford University Press 707 pp.

Goebel, K. 1906: Archegoniatenstudien X. Beitrage zur Kenntnis asutralishcher und neuseelandischer Bryophyten. Flora 96: 1-202.

Grolle, R. 1983: Nomina generica Hepaticarum; references, types and synonymies. Acta Botanica Fennica 121:1-62.

Hamlin, B. G. 1972: Hepaticae of New Zealand, Parts I and II. Index of binomials and preliminary checklist. Records of the Dominion Museum 7: 243-366.

Hasegawa, J. 1983: Taxonomical studies on Asian Anthocerotae III Asian species of Megaceros. Journal Hattori Botanical Laboratory 54:227-240.

Hodgson, E. A. 1972: New Zealand Hepaticae (Liveworts) XX A miscellany of taxonomic notes, part 3. Journal Royal Society of New Zealand 2: 109-118.

Hooker, J. D. and Taylor, T. 1844: Hepaticae Novae Zelandiae et Tasmaniae; being characters and brief description of the Hepaticae discovered in the Islands of New Zealand and Van Diemen's Land, during the Voyage of H. M. Discovery ships Erebus and Terror, together with those collected by R. C. Gunn and W. Colenso. London Journal of Botany 3: 575.

Khanna, L. P. 1944: On two new species of Megaceros with notes on M. arachnoideus, M. denticulatus, M. giganteus, and M. grandis Farlowia 1 (4): 515-523.

Lehmann, J. G. C. 1857: Novarum et minus cognitarum stirpium. Pugillus 10: 25, Meissner, Hamburg.

Mitten, W. 1865-73: Jungermanniae and Marchantiae In Seeman, B., Flora Vitiensis pp. 404-419 London.

Pearson, W. H. 1923: Notes on a collection of New Zealand Hepaticae. University of California Publications in Botany 10: 307-370.

Stephani, F. 1892: A revision of Colenso's Hepaticae, with descriptions of new species collected by him. Journal of the Linnean Society of London (Botany) 29: 263-280.

Stephani, F. 1893: Hepaticarum species novae. Hedwigia 32: 141.

Stephani, F. 1916: Species hepaticarum 5: 849-1008. Geneva.

Taylor, T. 1846: In Gottsche, C. M.; Lindenberg J. B. G.; and Nees ab Esenbeck. Synopsis hepaticarum: 580. Hamburg.