Cephaloziella aenigmata
Cephaloziella aenigmata R.M.Schust., Nova Hedwigia 63: 20. f. 2. 1996.
Holotype: New Zealand, South Is., Paparoa Ra., NE of Mt. Euclid, 3800–4300 ft., Schuster 84-1577.
Plants creeping amidst other hepatics, usually as isolated plants or somewhat gregarious, whitish, decolorate, translucent to transparent, the stem readily visible through the hyaline bleached mature leaves, only the distal leafy shoot sectors sporadically brownish purple to reddish purple or vinaceous; plants small, the leafy shoots 150–250 µm wide, to 6 mm long, the leafy axes sporadically becoming flagelliform and microphyllous. Branching sparing and irregular, the branches chiefly (?all) lateral-intercalary; stoloniform, microphyllous, geotropic axes sparingly produced, originating from ventral face of stem, colorless. Rhizoids colorless, infrequent, absent or nearly so on normal-leaved axes. Stems wiry and rigid, colorless above, pale brownish with age, with gradual transition from an exceedingly thick-walled outer cortical layer (lumina small, round or oval, free walls exceptionally thick) to a somewhat larger-celled hyaline medulla formed of moderately incrassate cells, a leptodermous central medulla lacking. Leaves stiffly, pectinately distichous, usually obliquely suberect (the lamina obliquely spreading, the lobes erect or suberect), the leaves, in situ, with the dorsal margin often feebly recurved, the leaves exceptionally densely imbricate (stem, in dorsal view of shoots, wholly hidden), transversely inserted and oriented, the leaves (flattened) subquadrate, ca. 180–200 × 180–210 µm, symmetrically bilobed to 0.55–0.75; lobes narrowly, acutely triangular, with straight or feebly arched sides, (7)8–11(12) cells broad at base, terminating in a single cell or often a uniseriate row of 2 cells, the apical cells subisodiametric (usually as broad as long) or weakly elongated, tapering to an acute summit, the tips never beaked; margins edentate or isolated leaves with a solitary tooth on ventral margin, but appearing ± finely crenulate because of the tubercle-like marginal swellings of the radial cell walls (swollen septa); sinus acute, in situ often with lobe margins somewhat recurved. Cells strongly thick-walled, often guttulate, the lumina rounded (especially so near ventral leaf bases, where cells are hyaline, exceptionally thick-walled); marginal cells rounded-subquadrate, only (7)8–11 × 8–12 µm; intramarginal cells in lobe bases somewhat larger, 10–12 × 15–20 µm to 12 × 12–14 µm, usually clearly larger and mostly longer than marginal cells; cell surfaces usually very coarsely papillose, the papillae dome-like, diverse in size, usually contiguous in and near lobe apices. Oil-bodies (Schuster, 1996a) (1)2–3 per lobe cell, smooth (and hardly perceptibly granular), small, not or hardly larger than chloroplasts, ca. 2.5 × 3.5 µm. Underleaves lacking. Asexual reproduction by colorless (when young), ellipsoidal or ovoid, smooth, 2-celled gemmae, ca. 7–8 × 13–15 µm.
?Dioecious. Androecia unknown. Gynoecia (only immature known) on elongated or ± abbreviated axes, with 2–3 gyres of progressively larger bracts, the innermost rounded-quadrate, bilobed to ca. 0.4–0.5, the lobes acute, entire, the disc sometimes with a blunt tooth below; bracteole free from bracts, small. Perianth (only very juvenile known) pluriplicate, the mouth lobulate-ciliolate, some cilia 1–2-celled, of long cells (6.5–8 × 18–20 µm to 6–7 × 21–30 µm) their tips narrowed, acute.
Distribution and Ecology : Endemic to New Zealand: South Island (1160–1310 m). Known only from the type, which occurred mixed with Nothogymnomitrion erosum, Radula sainsburiana, Cheilolejeunea albovirens, Paraschistochila conchophylla, Jamesoniella and the filmy fern Hymenophyllum armstrongii over a damp rock wall in a thicket of Nothofagus menziesii – Dracophyllum traversii in the otherwise penalpine zone.
Comments : The leaves are unusually densely imbricate for the genus, and little or no stem is visible in lateral view. The species is also unusual in that the mature shoots have decolorate leaves and the stem is readily visible through the ± hyaline leaves; only the shoot apices are reddish pigmented. Leaf cells are notably thick-walled, with a guttulate lumina, and the surface is densely covered with hemispherical coarse papillae.
