Zoopsidella R.M.Schust.
Zoopsidella R.M.Schust., Nova Hedwigia 10: 24. 1965.
Type: Zoopsidella cynosuranda (Spruceex Steph.) R.M.Schust. (≡Zoopsis cynosurandra Spruceex Steph.)
Plants markedly distichous-leaved and strongly complanate, prostrate or creeping, light to pale green, nitid, rather translucent, small, the tips occasionally becoming flagelliform, the plants small to medium, to 1.6 mm wide. Branching sparing and irregular, the branches normally ventral-intercalary, often stoloniform and microphyllous; Frullania -type branches sometimes also present (in ours). Stem with 6 or 10–13 rows of large, hyaline cortical cells forming a conspicuous hyaloderm, the dorsal rows of large cells in surface view irregularly polygonal and not or little elongated, the cells of the ventral merophyte smaller than the dorsal and lateral cells; medullary cells markedly smaller, firm-walled. Rhizoids at the bases of underleaves or (extraterritorial species) sometimes also from ventral side of apical and subapical leaf cells, often with bulbous apices. Leaves typically formed of many cells, laterally spreading, nearly or quite flat, almost longitudinally inserted, leaving a broad strip of 2–3(5) cell rows leaf-free; leaves symmetrically 2-lobed to 0.2–0.4 (in ours), or strongly asymmetric and with a reduced or vestigial dorsal lobe; lobes ending in crescentic slime papillae attached along their longer walls, or without these cells (our species). Cells very large, leptodermous; surface smooth. Oil-bodies (Schuster, 2000a) glistening and almost homogeneous or, at most, obscurely botryoidal. Underleaves small or vestigial. Asexual reproduction absent.
Dioecious, autoecious (in ours), or paroecious. Androecia sometimes terminal but becoming intercalary on leading leafy axes, or sometimes on small, ventral-intercalary branches; bracts pouched at base, bilobed; antheridia 1 per bract, the stalk uniseriate. Gynoecia normally on feeble, short, ventral-intercalary branches; bracts and bracteoles of innermost series bifid to 0.5–0.85, the lobes entire or subentire. Perianth fusiform-trigonous, the basal cells much larger than median and apical cells, the mouth narrow, deeply 6-fid; perianth 1-stratose.
Seta with 8 rows of large outer cells surrounding 4 rows of internal cells. Capsule wall 2-stratose; outer layer of cells rectangular, usually both faces of alternating walls with sinuous-nodular thickenings; inner layer of cells with well-defined semiannular bands.
Spores delicately areolate.
A genus of 8 species, of which only one occurs in New Zealand. The other species are Neotropical and range north to the Antilles; for these see Schuster (1999b). The genus has three subgenera: subg. Hyalolepidoziopsis R.M.Schust., with only our species, subg. Hypozoopsis R.M.Schust. and subg. Zoopsidella.
All species of Zoopsidella have large, flat, lamelliform leaves, unlike a number of Zoopsis species, in which leaves are usually highly reduced to a very few, specialized cells. Also, Zoopsidella has a seta of the 8+4 type vs. a seta with 8 epidermal cell rows enclosing numerous, much smaller internal cell rows in Zoopsis.
References: Schuster (1999b, 2000a).
The species treatment is adapted, with considerable modification, from Schuster (1999b).
