The Hepaticae or liverworts form the second of the two classes into which the Bryophyta are divided. The two main distinctions between the classes are said to be, that of the liverworts have unicellular rhizoids, and spiral elaters mixed with the spores in the capsules (except in Ricciaceae). The non-thalloid or foliose hepatics differ from the mosses, generally speaking, in the following respects; in the rudimentary and short-lived protonema; in the bi-lateral leaves always without a midrib, and frequently bilobed; in the usual presence of stipules; in the capsule remaining in the more or less delicate calyptra (destitute of lid) till the spores are mature, then developing a hyaline and evanescent, sometimes elongated seta, and commonly dehiscing by four valves, peristome always absent. Generally speaking, the liverworts prefer wetter conditions than the mosses.

Probably the earliest collection of New Zealand hepatics was that of Archibald Menzies, gathered at Dusky Sound in 1791. These were described and figured by Sir William Hooker in his Musci Exotici in 1818. Sir Joseph Hooker's Botany of the Antarctic Voyage, in several volumes spread over many years, contains the descriptions of plants collected by Hooker in the subantarctic islands, Northland (N.Z.), and Tasmania, together with many of Colenso's. Dr. T. Taylor and W. Mitten were responsible for these descriptions. In 1867, Part II of Hooker's Handbook of the New Zealand Flora was published, a portion of which is devoted to the liverworts, with an Appendix by Mitten. Dealing with plants collected by the earlier botanists, the Handbook has been the basis of all our work on New Zealand Hepaticae. Stephani's famous Species Hepaticarum in 6 volumes, 1900-1924, includes descriptions of all New Zealand species to date. Local Floras of both hemispheres are useful for obtaining information about hepatics, the handiest, perhaps, being L. Rodway's “Tasmanian Bryophyta II, Hepatics.”^*

The system of classification used in this paper, is that set out by Evans.^**

Three of the four orders of the Hepaticae are represented in New Zealand.

Order 1 Jungermanniales

Plants both foliose and thalloid, the latter not differentiated into layers of different tissue and without pores. Tuberculate rhizoids not present. Sexual organs usually in groups, but not on special pedunculate receptacles. Capsule, usually on a long seta, opening by 4 valves. Apical growth of stem or thallus proceeds from a single cell.

Sub-order 1 Haplomitrineae

• Family Haplomitriaceae, Calobryum.

Sub-order 2 Jungermannineae (Jungermanniales acrogynae)

• Family Ptilidiaceae, Herberta, Mastigophora, Hygrobiella, Ptilidium, Bleoharostoma, Isotachis, Lepicolea, Lepidolaena, Trichocolea.
• Family Lepidoziaceae, Bazzania. Acromastigum, Psiloclada, Lepidozia.
• Family Cephaloziaceae, Cephalozia, Lembidium, Zoopsis, Adelanthus, Marsupidium.
• Family Cephaloziellaceae, Cephaloziella.
• Family Harpanthaceae, Lophocolea, Chiloscyphus, Mylia, Geocalyx, Saccogyna.
• Family Jungermanniaceae, Lophozia, Sphenolobus, Anastrophyllum, Cuspidatula, Chandonathus, Jungermannia, Jamesoniella, Acrobolbus, Symphyomitra.
• Family Marsupellaceae, Gymnomitrium.
• Family Plagiochilaceae, Plagiochila, Tylimanthus.
• Family Scapaniaceae, Diplophyllum.
• Family Schistochilaceae, Schistochila, Balantiopsis.
• Family Porellaceae, Porella.
• Family Goebeliellaceae, Goebeliella.
• Family Radulaceae, Radula.
• Family Frullaniceae, Frullania.
• Family Lejeuneaceae, 18 genera, originally subgenera of Lejeunea, keyed separately.

Sub-order 3 Metzgerineae (Jungermanniales anacrogynae)

• Family Treubiaceae, Treubia.
• Family Fossombroniaceae, Fossombronia Petalophyllum.
• Family Pelliaceae, Calycularia, Allisonia.
• Family Pallavicineaceae, Pallavicinia, Symphyogyna, Hymenophytum.
• Family Metzgericeae, Metzgeria.
• Family Riccardiaceae, Riccardia.
• Family Monocleaceae, Monoclea.

Order 2 Marchantiales

Thalloid, vegetative body consisting of epidermis, an upper zone of green tissue with or without air-chamber (with pores) and a lower page 22 zone of large-celled hyaline tissue. Rhizoids smooth and tuberculate, ventral scales or ridges often present. Special cells with oil-bodies present.

• Family Marchantiaceae, Marchantia, Lunularia.
• Family Rebouliaceae, Reboulia, Asterella, Plagiochasma.
• Family Targioniaceae, Targionia.
• Family Ricciaceae, Ricciocarpus, Riccia.

Order 3 Anthocerotales

Thalloid, with smooth rhizoids, no ventral scales. Cells usually with one large chloroplast. Sporogonium with a bulbous foot, a sheath, and a long sessile capsule, bursting from the top downwards into two valves, columella generally present. Antheridia sunk in the upper surface of the thallus, ultimately bursting free.

Family Anthocerotaceae, Anthoceros, Aspiromitus (on the authority of Pearson), Megaceros, Dendroceros.

Key to Genera

Legends to Figures
Plate 1
1. Diplasiolejeunea lyratifolia ventral, showing duplicated stipules, one for each leaf, × 10.
2. Diplcphyllum domesticum dorsal, showing small dorsal leaf-lobes, × 5.
3. Strepsilejeunea Curnowii ventral, showing acute, decurved leaf-apices, × 10.
4. Bazzania Novae-Zelandiae ventral, showing incubous leaves and ventral axillary branching, × 4.
5. Bazzania Novae-Zelandiae dorsal, showing incubous leaves, × 4.
6. Balantiopsis diplophyllum dorsal, showing terminal marsupium, × 6.
7. Chiloscyphus ammophilus dorsal, showing succubous leaves, × 5.
8. Lepidozia tetradactyla dorsal, showing deeply divided leaves and lateral perianth, × 8.
9. Radula Levieri ventral, showing lobules, absence of stipules and spent capsule, × 10.
10. Lophocolea subporosa dorsal, showing terminal perinath with 3rd keel dorsal, × 5.
11. Cephaloziela sp., dorsal, showing deeply pluri-plicate perianth and bi-fid leaves, × 12.
12. Goebeliella cornigera ventral, showing double lobules and entire stiples, × 10
13. Elaters, A Metzgeria violacea monospiral, × 125; B. Frullania rostallata monospiral; C. Radula Levieri bispiral.
14. Pseudolates of Anthoceros × 100.
15. Cells of Lejeunea sp. without trigones, ca. 40 microns.
16. Rhizoids; D. Reboulia hemispherica, smooth; E. Lunularia cruciata, tuberculate, × 125.

17. Asterella australis × 16, F carpocephalum showing laciniate perianth, × 4.
18. Targionia hypophylla with terminal valves, × 1½.
19. Riccardia marginata showing absence of nerve and lateral calyptra, × 3.
20. Anthocercs with linear dehiscing capsule, nat. size.
21. Marchantia with male carpocephalum and rounded gammae cups; G. female carpocephalum showing involucres between the rays, nat. size.
22. Metzgeria furcata dorsal with ventral calyptras showing, also mid-rib and ciliate margins; H. ventral with male branches, x. 4.
23. Reboulia hemisphaerica, carpocephalum, underneath view showing bi-valved involucres, × 2½.
24. Plagiochosma australe with invol. lobes opening vertically, × 2½.
26. Lunularia cruciata with lunate gemmae cups, nat. size.
27. Sypmhyogyna hymenophyllum showing involucral scales and calyptras; I. sterile archegonia adhering to calyptra, × 2.
28. Pallavicinia Lyellii, J. invol. cup, K. perianth with calyptra included, nat. size.
29. Hymenophytum phyllanthus, L. basal ventral invol. cup, M. perianth, calyptra included, nat. size.
30. Dehisecnt capsules; N. Taxilejeunea Colensoana showing valves not divided to the base, × 10; O. Plagiochila × 7; P. Fossombronia × 7; Q. Metzgeria furcata with elaterophones × 10; R. Asterella × 5.

Lejeuneaceae

The ever-increasing genera of this family are in some cases imperfectly understood and hard to separate. It is doubtful if both Drepanolejeunea and Harpalejeunea are present in New Zealand, as recorded by Stephani. Physocolea and Leptocolea were originally divisions of Spruce's sub-genus Cololejeunea. These two divisions are now treated as genera, but the original name of “Colojeunea” has been substituted for that of “Physocolea,” as used by Stephani, and Herzog.^*

Key To New Zealand Genera

A Glossary of Terms Used in This Paper.

• Antheridium, the organ containing the male cells.
• Archegonium, a flask-shaped organ containing the embryo sporophyte, (Fig. 27).
• Axil, the angle between the stem and a leaf.
• Bifid, 2-cleft to half-way or thereabouts, (Fig. 11).
• Capsule, the sporangium or terminal portion of the sporophyte which actually contains the spores, (Figs. 9, 25).
• Carpocephalia. See receptacle.
• Calyptra, the inmost protective covering of the sporophyte, being the remains of the archegonium. Always present in the fructification, though sometimes fused with the perianth, (Fig. 19).
• Cauline, pertaining to the stem, used of leaves and stipules in contradistinction to those of the involucre.
• Chloroplast, a green body in plant cells.
• Ciliate, fringed with cilia or hair-like outgrowths, (Fig. 22).
• Columella, the central column in the capsule of the Anthocsrotaceae.
• Complicate, folded together.
• Cuspidate, terminating in a sharp rigid point cr cusp.
• Decurved, bent towards the ground or ventral aspect. (Fig. 3).
• Dehiscing, the opening of the capsule in different ways to let the spores escape, (Fig. 20).
• Dorsal, the front side of a leaf or stem, or that further from the ground or substratum, antical, (Fig. 2).
• Elaters, long and slender single or compound cells mixed with the spores, with spiral thickenings in their walls, (Fig. 13, A, B, C).
• Elaterophores, elaters, maybe of a different shape which remain fixed in a tuft at the base of the capsule in Pelliaceae, or at the top of the valves in Riccardia and Metzgeria, (Fig. 30, Q.).
• Emergent, used in speaking of a perianth which is partly concealed by the involucral leaves.
• Entire, stipules without an apical sinus in Frullania and Lejeunea, or any margin without projections or incisions.
• Epidermis, the uppermost layer of cells of a thallus.
• Evanescent, of short duration.
• Falcate, sickle-shaped.
• Fimbriae, narrow processes.
• Flagelliferous, bearing longly attenuated branches.
• Foliose, with leaves, used of hepatics as opposed to the thalloid group.
• Globose, globular or spherical.
• Homomallous, descriptive of leaves all pointing in the same direction.
• Hyaline, glassy, transparent.
• Imbricate, overlapping like the tiles of a roof.
• Immersed, descriptive of a perianth that does not protrude beyond the involucral leaves.
• Incubous, when the leaf is so inserted that the dorsal margin overlaps the ventral of the leaf above it, (Figs. 4 and 5).
• Infra-Axillary, branches contiguous to the outer base of the leaves.
• Innovations, shoots which arise from below the perianth.
• Intra-Axillary, when the branches spring from the inside of the leaf-axil.
• Involucre, the outermost protective covering of the sporophyte, in the thalloid hepertics a ring or cylinder of tissue, or scales; in the foliose, consisting of enlarged leaves, (Figs. 21, 23).
• Lacerate, jagged or torn.
• Lobule, when the ventral lobe of a leaf is smaller than the dorsal, it is spoken of as the lobule, (Fig. 9).page 32
• Marsupium, a fleshy sack enveloping the sporophyte, serving the purpose of a perianth, (Fig. 6).
• Median, belonging to the middle of a thallus, leaf, etc.
• Multistratose, when cells are arranged in several layers.
• Obovate, inversely ovate, attached by the smaller end.
• Papillae, minute processes arising from the cuticle of the cells.
• Papillose, bearing papillae.
• Perianth, the envelope surrounding the calyptra, (Fig. 8), strictly speaking, formed of united leaves. In the thalloid hepatics often known as the pseudoperianth.
• Plicate, with longitudinal folds.
• Pluriplicate, with many folds or plicae, (Fig. 11).
• Protonema, a simple structure from which the sexual generation is formed.
• Pseudoelaters, a row of irregularly shaped sterile cells, often geniculate, without spiral bands, found in the capsules of Anthoceros, (Fig. 14).
• Receptacle, an elevated and expanded portion of the thallus modified to bear the sexual organs, = carpocephalum.
• Rhiziferous, bearing rhizoids.
• Rhizoids, long hairlike outgrowths, resembling rootlets, (Fig. 15).
• Seta, the stalk of the capsule.
• Sinus, the notch, acute to lunate, between two points.
• Sporophyte, the asexual generation consisting of the capsule (sporangium), its seta and base, sometimes called the sporogonium.
• Squarrose, set at right angles to the stem.
• Stipules, the third or ventral row of leaves sometimes called amphigastria or underleaves, (Fig. 1).
• Stomata, openings through the epidermis of the capsule in Anthocerotaceae, bounded by 2 guard-cells.
• Succubous, when the leaf-base is so inserted that the dorsal margin of the leaf overlaps the ventral margin of the leaf below it, (Fig. 7).
• Terminal, proceeding from the apical cell of stem or thallus, (Fig. 10).
• Thalloid, consisting of or resembling a thallus, frondose.
• Thallus, a flat vegetative structure not differentiated into stem and leaves.
• Transverse, when the leaf insertion is straight across the stem.
• Trigones, thickenings of the walls where 3 or more cells meet, (Fig. 15).
• Trigonous, 3-angled.
• Unistratose, arrangement of cells in one layer.
• Undulate, wavy.
• Ventral, the back side of leaf or stem, or that facing the ground or substratum.