Zoopsis bicruris Glenny & E.A.Br.
Holotype: New Zealand, Westland, Blackball, Croesus Track, 300 m elevation, Glenny 8281 (CHR 5361880); isotypes: (NSW, WELT).
[Plate 9C; Fig. 110: 4, oil-bodies, p. 486]
Plants creeping, glossy, yellow-green, the shoots to 10 mm long, to 0.45 mm wide at the widest point, widest below the tip, never attenuate, the apex acute. Branching frequent, the branches strictly of ventral-intercalary type; ventral-intercalary flagellae present. Rhizoids absent. Axes broad and flat, plano-convex to biconvex, comprised uniformly of thin-walled cells; dorsal surface comprised of 2 rows of large, inflated cells that form the lateral margin of the axis, the cells 210–250 µm wide × 130–150 µm long; ventral surface comprised of 4 rows of cells, the median 2 rows composed of cells 47–88 wide × 40–70 µm long, the outer 2 rows composed of cells 95–150 µm wide × 53–68 µm long; medullary cells in 9 rows, thin-walled, forming a central strand. Leaves distant, with 2 dorsal cortical cells intervening between successive leaves on each side of axis; leaves transversely oriented, bifid, consisting of 4 cells: the basal pair of cells (the “disc”) touching, small and rather inconspicuous, the dorsal “disc” cell on the side of the stem over the wall between 2 dorsal stem cells, the ventral “disc” cell at the junction of 2 dorsal stem cells and 2 ventral stem cells, the basal cells each distally with one large and conspicuous ovoid cell (the “lobes”); basal cells 30–32 µm in diam., packed with oil-bodies; distal cells each 26–41 × 42–88 µm, without oil-bodies and chloroplasts each in turn capped by a slime papillae that eventually collapses and is usually not visible. Oil-bodies in dorsal cortical cells 2–5 per cell, inconspicuous and occupying a tiny fraction of cell lumen, opaque, pale grey, hyaline and glistening, finely papillose, globose to elliptic; in leaf cells 6 per cell, conspicuous but still occupying a small fraction of lumen, coarsely papillose, with spherules larger than those of the cells. Underleaves vestigial, distant, separated by 3 pairs of ventral cortical cells, bifid, consisting of 2–3 basal, subisodiametric cells (the “disc”), each with an inflated, sausage-shaped cell terminating in a slime papilla.
Dioecious. Androecia unknown. Gynoecia on short ventral-intercalary branches; bracts and bracteoles bifid, the terminal cell of lobes internally sparsely papillose to smooth, the cells of bracts mostly hyaline, without oil-bodies. Perianth cylindrical, the apex unlobed but dentate by ca. 13 teeth, each tooth of 1–2 cells.
Seta ca. 1.6 mm long at maturity, with 8 rows of outer cells surrounding inner core of ca. 9 rows of smaller cells. Capsule wall bistratose, 20 µm thick.
Spores 13–14 µm in diam., finely reticulate-ridged. Elaters 9–12 µm wide, bispiral.
Distribution and Ecology : Endemic to New Zealand: South Island (300–960 m), Chatham Islands. In the South Island known from Westland and Western Nelson EPs, the southern limit near Lake Kaniere (Mt. Brown), the northern limit at Stockton Plateau.
Found in forests of Dacrydium cupressinum, Metrosideros umbellata and Weinmannia racemosa and stunted forest or scrub of Lepidothamnus intermedius, Halocarpus biformis, Nothofagus solandri var. cliffortioides, Metrosideros umbellata and Lagarostrobos colensoi. Usually on humus on the floor of root caves under Metrosideros umbellata, Weinmannia racemosa or Lepidothamnus intermedius. Accompanying species in these cave sites are Acromastigum colensoanum, Bazzania nitida, Categonium nitens, Kurzia hippuroides, K. tenax, Psiloclada clandestina, Rhizogonium distichum, R. pennatum, Zoopsis argentea, Z. ceratophylla, Z. leitgebiana, Z. matawaia and Z. setulosa. Found on Mt. Augustus (Stockton Plateau, 960 m) on an overhanging wet rock face in a deeply shaded boulder pile under Nothofagus solandri, Halocarpus biformis and Metrosideros umbellata scrub where it was mixed with Telaranea inaequalis and Acromastigum cunninghamii.
Comments : Zoopsis bicruris is similar to Z. nitida in having very reduced leaves giving the shoots a worm-like appearance. The species is unique in the genus in its complete lack of terminal branching, the branches being exclusively ventral-intercalary in origin. Zoopsis bicruris differs from other Zoopsis species with reduced leaves (Z. nitida, Z. argentea and Z. setulosa) in having clavate shoot apices that narrow abruptly to an acute tip. This feature is distinctive in the field. The leaf-disc cells are only ca. 30 µm in diam., much less than the cortical stem cells of ca. 100–200 µm diam., whereas in other species of Zoopsis with reduced leaves, the disc cells are equal in size to the cortical stem cells. This gives the stem in those other species the appearance of being 4 cells wide whereas in Z. bicruris the stem is clearly only 2 cells wide on the dorsal surface. The leaf lobe cells are inconspicuous and collapse when the shoots become partially desiccated, giving the appearance in the field of a leafless stem 2 cell rows wide.
