Telaranea perfragilis J.J.Engel & G.L.Merr.
Telaranea perfragilis J.J.Engel & Merrill, Fieldiana, Bot. 44: 72. f. 20: 7–14. 2004, nom. nov. pro Telaranea fragilis J.J.Engel & Merrill, Novon 9: 341. f. 2. 1999, non T. fragilis Mizut., J. Hattori Bot. Lab. 40: 449. f. 1. 1976 (Philippines).
Holotype: New Zealand, North Is., North Auckland Prov., NE Waitakere Ranges, Swanson University Reserve, Tram Valley Road, 95 m, Engel 20465 (F); isotype: (CHR).
Plants delicate, flexuous, prostrate in thin straggling mats or as isolated strands among other bryophytes, glaucous, whitish to bluish green, dull and distinctly water-repellent; shoots medium, to ca. 1 cm wide, including branches. Branching loosely and irregularly 1-pinnate, the branches of the Frullania type; branch half-leaf bifid, linear; first branch underleaf undivided, subulate, inserted on the ventral side of branch at branch base. Ventral-intercalary branches present, both leafy and stoloniform. Stems dorsiventrally flattened, with cortical cells distinctly differentiated, in 9–12 rows, thin-walled, the dorsal cortical cells much larger than medullary cells; medullary cells ca. 16. Rhizoids issuing from distal tier of underleaf disc cells. Leaves fragile, typically erose-truncate (the lobes all or mostly broken off and often the distal tiers of disc cells missing), widely spreading, at times nearly at right angles to stem, distant to loosely imbricate, plane, strongly horizontally oriented, the disc in the same plane as the dorsal surface of the stem or nearly so, the insertion distinctly incubous; leaves 260–290 µm wide, the fragmented leaf 280–390 µm long (including basal cell of lobe), 465–505 µm long with lobes, leaves subsymmetric, 4-lobed to ca. 0.4, the lobes ± parallel with disc margins or only slightly divergent, shorter than the disc. Lobes (when present) subcaudate, 2 cells broad at base, terminating in a uniseriate row of 6–7 cells, distinctly constricted at the septa (especially in basal portion); lobe cells thin-walled, the basal pair of lobe cells and the basal cell of uniseriate row barrel-shaped and bulging. Disc ± symmetrically quadrate to subrectangular, 5–6(7) cells long (from median sinus base to leaf base), mostly 8 cells wide throughout; margins about equal in length, distinctly crenulate due to bulging marginal cells, ± straight to weakly arched. Cells of disc in regular longitudinal rows, thin-walled but firm or moderately thick-walled, trigones minute or absent; median disc cells large, subquadrate, 33–45 µm wide × 40–52 µm long, the basal row somewhat longer, forming an obvious tier; surface with a finely granular and faintly striate coating. Underleaves much smaller than leaves, widely spreading, distant, often gently curved dorsally, 4-lobed to 0.75–0.85, the lobes widely divergent, ciliiform, consisting of a uniseriate row of 3–4 elongated, thin-walled cells, inserted on 2 disc cells, terminating in a slime papilla; disc abbreviated, 2 cells high, 8 cells wide. Asexual reproduction evidently by fragmentation of leaf lobes and disc.
Plants apparently dioecious. Androecia on short, abbreviated, ventral-intercalary branches lacking normal vegetative leaves; bracts rather closely imbricate, strongly dorsally assurgent, deeply concave, 2–3-lobed, each lobe terminating in a uniseriate row of (2)3 moderately elongated, thick-walled cells; lamina margins irregularly minutely crenulate by few cells with the free margin bulging, otherwise with a few slime papillae; bracts monandrous; antheridia large for bract size, the stalk biseriate; bracteolar antheridia absent. Gynoecia not seen.
Distribution and Ecology : Endemic to New Zealand: North Island (95–820 m). Known from Southern North Island (Ruamahanga Valley), Gisborne (Pongakawa River), Auckland (Auckland City, Coromandel Peninsula) and Northland (Waipoua) EPs. The species occurs on moist, clayey banks or at times over rock in forests. The type occurred on a vertical clayey bank above a small stream in an old Kunzea forest with Agathis australis and Phyllocladus trichomanoides.
Comments : Plants of this species are delicate and fragile; in shoots freshly mounted in water the leaves often can be observed breaking apart (Fig. 63: 10, arrow), and it is likely that detached lobe and disc cells function as gemmae. Hodgson (1956) cited populations referable to this species and included them under her treatment of Lepidozia centipes. Telaranea perfragilis resembles T. centipes in the conspicuously turgid, bulging cells of the disc margins and lobes, but the leaves are 4-lobed in T. perfragilis and the disc is typically parallel-sided and 8 cells wide throughout (Fig. 63: 7). In T. centipes the disc is cuneate and up to 15 cells wide in the distal portion and the leaves are sometimes 5–6(7)-lobed on robust main shoots. In addition, the basal cells of the uniseriate row in T. perfragilis are fat and bulging, but the distal portion of the uniseriate row, when present, is slenderly tapering, with narrower, more elongate cells (Fig. 63: 8).
