Cephaloziella pellucida R.M.Schust.
Cephaloziella pellucida R.M.Schust., Nova Hedwigia 63: 57. f. 13. 1996.
Holotype: New Zealand, South Is., Canterbury Prov., Arthur’s Pass Natl. Park, Temple Basin, 4500–4800 ft., Schuster 84-899.
Plants erect, growing amidst mosses, straggly, when dry white and opaque, when moist translucent aside from the ± opaque medulla of the stem, only the uppermost leaves of complanate-leaved shoots locally pigmented brownish purple, the shoots very small (lower, terete or subterete leafy shoots only 130–185 µm wide, apical distichous-leaved sectors to 270–300(400) µm wide, strongly complanate, the shoot tips sharply upcurved), the sinuous shoots long and stringy, under 5–6 mm long but indeterminate in length. Branching very sparing and irregular, the branches all lateral-intercalary, soon equal in vigor to main axis. Stem wiry and rigid, the cortical cells unpigmented, hyaline, undifferentiated, of notably thick-walled cells, the cortical cells in surface view subquadrate to short-oblong, with strongly thickened longitudinal and transverse walls, the surface striolate; medullary cells with pale yellowish or yellowish brown, very thick walls, the lumina guttulate, the cells averaging a little smaller than those of cortex. Rhizoids few, only on lower shoot sectors, scattered, short, hyaline, usually solitary. Leaves varying greatly in form, density and orientation: on lower shoot sectors sheathing in their basal 0.5–0.65, with ± spreading lobes, often with the spreading lobes conspicuously denticulate (at least on ventral margins and often on lobes); leaves on the remote- to contiguous-leaved sectors often smaller, 130–145 µm wide × 165–175 µm long, asymmetrically ovate, the dorsal half of leaf smaller and shorter, the dorsal margin straight or weakly arched; ventral half of leaf broader and longer, the ventral margin distinctly ampliate below and there conspicuously denticulate or crenulate with thick-walled cells, often elongated obliquely or at right angles to the margin; leaves asymmetrically bifid to 0.4–0.45, the lobes sharp, subentire to obscurely crenulate-denticulate with projecting or bowed-out free cell walls, the ventral lobe usually 4–5 cells broad, the dorsal lobe shorter, (3)4 cells broad. Leaves of upper sector of stem densely imbricate, the stem nearly or quite hidden in dorsal aspect, somewhat dorsally assurgent, complanate, sheathing only at the base and with the lobes widely spreading, the leaves more narrowly ovate, to 135 µm wide × 210–225 µm long, otherwise like the lower leaves, but denticulation of ventral margin often less pronounced. Cells everywhere thick-walled and lacking trigones, the lumina rather angular with rounded corners; cells in lobes tending to be inflated, the convexity often strongly thick-walled, sometimes lenticular (visible sometimes in cells of the ill-defined keel of complanate leaves); marginal cells in and near lobes 11–14 µm, measured tangentially; cells at lobe bases variable, 11–13 µm wide × 13–17 µm long to (ventral lobe) 13–17 µm wide × 13–18 µm long; cells in an ill-defined median basal field irregularly oblong, considerably larger and conspicuously elongated, the largest 11–17 × 21–30 µm; surface smooth. Underleaves lacking, not even slime papillae discernable, the ventral merophyte 1 cell broad. Asexual reproduction absent.
Androecia and gynoecia unknown.
Distribution and Ecology : Endemic to New Zealand: South Island (1370–1465 m). Known only from the type, among Distichium capillaceum in drip-wet crevices of cliff.
Comments : A distinctive plant with a number of features unique to the genus. 1) The shoot apices are complanate and artificially somewhat flattened and the tips are strongly upcurved, and in this distal sector the leaves are folded, densely imbricate and rather dorsally assurgent. This is the sector of the shoot that is exposed in situ, since only the distal portions of the plants are visible between the tufts of the moss Distichium (Schuster, 1996a). The lower sector of the shoot appears quite different: lower leaves ensheath the stem except for the narrowly acute lobes, which are stiffly obliquely spreading. 2) Leaves are asymmetrical, with the lower half of the ventral margin ampliate and denticulate or crenulate-denticulate by cells that are elongated at right or oblique angles to the leaf margin. 3) Plants have a peculiar bleached and translucent aspect, the leaves transparent and the cortical cells ± hyaline. Plants lack wall pigments except the spreading lobe tips of the uppermost leaves may have weakly warm brown or purplish brown pigmentation. 4) Leaves have a distinctive areolation, with presence of a median basal field of larger, conspicuously elongated cells. Schuster (1996a) remarked that species of Cephaloziella otherwise have basal cells that may be appreciably larger, but they never become conspicuously elongated and that mostly there is at best a slight increase in cell size from median to basal cells.
A more definitive taxonomic placement of this species must await discovery of gametangia.
