Monographs Details: Lopholejeunea colensoi Steph.
Authority: Thiers, Barbara M. & Gradstein, S. Robbert. 1989. Lejeuneaceae (Hepaticae) of Australia. I. Subfamily Ptychanthoideae. Mem. New York Bot. Gard. 52: 79 p.
Description:Species Description - Autoicous or dioicous? (androecia not seen); plants to 1 cm long x 1.0-1.4 mm wide, brown in the dried condition, on bark. Branching usually Lejeunea-Xype, occasionally also Frullania-type, growth habit deliquescent. Stems 100-110 /um in diam., in cross-section composed of 12 epidermal cells surrounding 10 medullary cells, epidermal cells and medullary cells thin-walled, approx, equal in size. Leaves diverging from stem at an angle of approx. 45-50°, imbricate, strongly convex, dorsal lobe broadly ovate, asymmetrical, 400-700 x 450-500 /um, apex obtusely rounded to acute, margins entire, acroscopic margin straight to rounded at dorsal base, slightly overlapping stem, basiscopic margin strongly rounded; marginal cells of dorsal lobe quadrate to rectangular, 13-20 x 10-20 /um, cells of midportion isodiametric to oblong, 25-48 x 25-38 /um, cells of leaf base similar, leaf cells thin-walled, trigones large, bulging, intermediate thickenings large. Lobules ovoid to oblong, 400-425 x 230250 /um, approx. 2/3 lobe length, strongly inflated, keel straight to rounded, with a sharp angle near point of attachment to lobe, free margin flattened, with one bluntly to acutely angled marginal tooth, sinus between tooth and distal edge of lobule forming a sharp 90° angle. Underleaves imbricate, orbicular to transversely oblong, 340450 x 350-570 /um, 3.5-4.5 x stem width, apex rounded, lateral margins entire, base cuneate to rounded, insertion straight to slightly arched. Gynoecia terminal on long branches, bracts widely spreading, bract lobes broadly obovate, averaging 700 x 640 /um, apex rounded, margins entire, bract lobules rectangular to ligulate, 450-475 x 200-250 /urn, apex acute or truncate, margins entire; bracteoles obovate to orbicular, average dimensions 700 x 680 /urn, margins entire. Perianths barely emergent, obovoid, averaging 800 x 500 /um (excluding ornamentation), lateral keels with very broad, often lobed wings extending almost the entire perianth length, ventral keels indistinct, ventral surface of perianth covered with broad, transversely inserted, irregularly shaped, recurved squamules. Androecia not seen.
Discussion:Type. New Zealand. North Island, Colenso s.n. (holotype, G; isotypes, BM, FH).
The vegetative morphology in Lopholejeunea is uniform enough to cause problems in the determination of sterile collections. In contrast, perianth structure in this genus varies remarkably. The most common perianth type is one with four to five keels, each of which bears small to large dentate or ciliate ornamentations. However, in L. erugata B. Thiers of Africa, the perianth is smooth and terete, lacking any trace of keels or ornamentation (Thiers, 1984). In subgenus Pteryganthus B. Thiers emend. Vanden Berghen, the perianths are compressed, and bear only two (lateral) keels. Each keel bears a very broad, entire-margined wing (Thiers, 1983). The perianth structure in L. colensoi is reminiscent of subgenus Pteryganthus in the presence of the two broad lateral keels, but in L. colensoi these keels are incised or lobed, and whereas the ventral surface of the perianth in subgenus Pteryganthus is smooth, that in L. colensoi is completely covered by large, irregularly shaped, recurved squamules. The combination of the bizarre perianth structure, convex lateral leaves and large lobules that are plane in the upper portion and strongly and abruptly inflated below make L. colensoi an isolated species within Lophole-jeunea, and thus we propose the following new subgenus to accommodate it.