Flora of New Zealand Series

Pleuroschisma sect. Lepidozia Dumort., Syll. Jungerm. Europ. 69. 1831.

Lepidozia (Dumort.) Dumort., Recueil Observ. Jungerm. 19. 1835, nom. cons.

Herpetium sect. Lepidozia Nees, Naturgesch. Eur. Leberm. 3: 31. 1838.

Lepidoziopsis E.A.Hodgs., Rec. Domin. Mus. 4: 105. 1962.

Type: Lepidozia reptans (L.) Dumort. (≡Jungermannia reptans L.), a Holarctic, widespread species.

Plants anisophyllous, firm, creeping to loosely prostrate to, more often, somewhat ascending, rarely stiffly erect, yellowish or whitish to olive-green, rarely brownish in life, rarely glaucous, medium-sized to vigorous, usually 0.5–2.5(4) mm wide. Branching irregular to regular, copiously 1- to 2- or 2–3-pinnate, of Frullania type, the lower terminal branches partly or mostly attenuate at the apices, often becoming rhizoid-bearing; Acromastigum -type branching present in a few species; Microlepidozia -type branches lacking; ventral-intercalary microphyllous or leafy branches in some taxa; lateral-intercalary branches lacking. Stem firm to rigid, with (18)20–32 or more rows of firm-walled cortical cells, typically little or at most moderately larger in diameter than those of adjoining medulla, not forming a discrete hyaloderm; subepidermal layers occasionally present, composed of thick-walled cells; medullary cells equal to or slightly smaller than cortical, firm-walled (the outer sometimes strongly so). Rhizoids of normal-leaved axes usually rare or absent, except at shoot bases, arising from underleaf bases; rhizoids on flagelliform shoots from all three merophyte rows. Leaves almost without exception 4-lobed or 4-lobulate on main shoots, incubous to subtransverse, the insertion extending to stem midline dorsally, the leaves typically asymmetrical, the dorsal half (and dorsal 1–2 lobes) larger than the ventral, the lobes usually many-celled (at bases 3–4 or more cells broad in most taxa), the cells similar to those of disc, the lobes usually sharp, often deflexed or inflexed in most taxa; disc margins entire or toothed to spinose-dentate or ciliate. Cells of disc irregularly arranged, not tiered, firm-walled, the lumina often rounded, the trigones concave-sided and mostly obscurely defined; median cells of disc mostly 18–25(40) µm wide; surface smooth or clearly papillose. Oil-bodies present in all leaf cells, colorless, usually (2)5–16 per cell, relatively large, usually botryoidal, less often subhomogeneous, often vestigial in subg. Glaucolepidozia. Asexual reproduction lacking or (Lepidozia fugax, occasionally in L. digitata) via fragmenting or caducous leaf lobes. Underleaves usually 0.5 or less the lateral leaves in area, transversely inserted, symmetrically 4-lobed on main shoots.

Dioecious, rarely (generitype, Lepidozia reptans) autoecious. Gametangial branches all short, devoid of normal leaves and underleaves, ventral-intercalary in origin (the androecia less frequently terminal on primary and secondary branches). Androecia typically spicate, smaller than vegetative shoots, the bracts concave, ± imbricate, lobed like (but usually more shallowly than) vegetative leaves; antheridia 1–2 per bract, the stalk 2-seriate; bracteoles small, lacking antheridia. Gynoecia with bracts and bracteoles identical, 4(6)-lobed to -lobulate, occasionally 2–4-dentate to -lobulate. Perianth fusiform or ellipsoidal-fusiform, bluntly trigonous in at least the narrowed distal sectors, the mouth usually crenulate to crenate-denticulate.

Seta with (8)12–16 large epidermal + 16 or more rows of much smaller internal cells. Capsule ellipsoidal to obloid, the wall 3–5(6)-layered; outer layer of cells often imperfectly tiered, the primary longitudinal and all transverse walls normally lacking pigmented thickenings, the secondary (longitudinal) walls with conspicuous radial (nodular) thickenings, often ± coalescing; inner layer of cells narrower, with radial (nodular) thickenings, ± connected by weak, often vestigial, tangential bands.

Spores papillose-vermiculate, less than 1.5× the diam. of the bispiral elaters.

Lepidozia is a large and polytypic genus, with perhaps ca. 80 species worldwide. Over half of these occur in an area extending from New Zealand (with 23 species) into Southeast Asia (e.g., New Guinea has ca. 17 species). Much of the morphological diversity found within the genus occurs in New Zealand. Of the seven subgenera of Lepidozia, five are present in New Zealand (see Engel and Schuster, 2001; Schuster, 1973). Absent from New Zealand are subg. Chaetolepidozia R.M.Schust., which ranges from Costa Rica south to Colombia and Ecuador, and subg. Cladolepidozia R.M.Schust. of the Paleotropics.

The species show a diverse ecology: they occur principally on soil, peat, or decaying logs, but also on soil-covered rocks, rarely a few invade even the lower trunks of trees. The large bulk of taxa occur in sheltered loci, but several ascend into the alpine zone, where they occur in damp sites of alpine grasslands, or on soil in crevices of crags or cliffs. All of our species are unisexual, but ♂ and ♀ plants often occur intermingled, and in many species sporophytes are produced, if infrequently so.

References: Hodgson (1956); Engel and Schuster (2001); Engel (2004a).

The following treatment of taxa is adapted and modified from Engel and Schuster (2001).