Telaranea granulata J.J.Engel & G.L.Merr.
Telaranea granulata J.J.Engel & Merrill, Fieldiana, Bot. 44: 103. f. 31. 2003.
Holotype: New Zealand, North Is., North Auckland Prov., Waima Forest, Hauturu Highpoint Track in vicinity of summit area of Hauturu Trig, off Waiotemarama Track, 650–680 m, Engel 22594 (F).
Plants exceedingly delicate, thread-like, minutely prickly, appressed, epiphyllous on fern leaves, pale green, highly nitid; shoots minute, to 525 µm wide with leaves. Branching distantly and somewhat irregularly 1-pinnate, the branches of Frullania type, the main axis terete, the branches dorsiventrally flattened; branch half-leaf undivided, occasionally bilobed; first branch underleaf consistently undivided, inserted on median ventral base of branch, biseriate at base, with a uniseriate row 2–3 cells long (or uniseriate throughout), terminating in a slime papilla. Ventral-intercalary branches occasional, at times becoming leading shoots. Stems slender, the cortical cells distinctly differentiated, thin-walled but firm, in 12 rows, in section somewhat larger than the medullary cells; medullary cells in 16 rows. Main shoots with 3–4 cortical cells intervening between successive leaves on either side, the branches with 2 (rarely 3) cells intervening between successive leaves on either side of branch. Leaves on main shoot rather distant, stiffly spreading, lending the stem a prickly aspect, the insertion weakly incubous to subtransverse, 390–495 µm wide (at tips of spreading lobes) × 245–310 µm long, deeply 3-lobed (4-lobed only on strongest shoots). Branch leaves 3-lobed, closely imbricate, the insertion moderately incubous, the insertion narrowly impinging on the 2 median rows of cortical cells, leaving a ± evident median strip along the dorsal side of the branch. Lobes ± equal in length, gradually tapering from base to apex, broadly incurved, moderately to widely divergent, from a biseriate base (at times with an additional biseriate tier), the uniseriate row 4–5 cells long; lobe cells thin-walled, the transverse septa at most feebly thickened in the corners, the lobes constricted at the septa; surface minutely scabrous. Disc 6 cells wide (8 in 4-lobed leaves); 2 cells high (1.5 cells high, the lobe bases connate for 0.5 or as little as 0.3 their length), consisting of a single tier of cells along the insertion, plus the paired basal cells of the lobes; basal tier of disc cells often incomplete, not extending to one or both margins, the disc then 0.5 cells high at margins. Cells of disc subquadrate, 13–19 µm wide × 24–36 µm long; surface smooth. Underleaves approaching the leaves in size, symmetrically 3-lobed (4-lobed on strongest shoots), the disc consisting of the partially connate basal cell pairs of the lobes; lobes biseriate at base, with a uniseriate row of 3(4) elongate cells (the distal cell shorter and often hooked), ending in a slime papilla. Rhizoids, when present, arising from swollen cells produced by vertical division of basal cell pairs, the disc then appearing bistratose in part.
Androecia and gynoecia not seen.
Distribution and Ecology : Endemic to New Zealand: North Island (650–680 m), Three Kings Islands. Known only from two specimens. The type is from a wind-pruned scrub consisting of Coprosma grandifolia, Melicytus ramiflorus and Olearia rani at 650–680 m. Plants occurred epiphyllous on Hymenophyllum sp. on a deeply shaded log with other filmy ferns. The Three Kings Islands specimen occurred on rock in a stream shaded by Kunzea canopy, growing with Distichophyllum, Balantiopsis, Leiomitra lanata and Riccardia.
Comments : This species is unusual for its deeply divided, 3-lobed leaves (Fig. 73: 1, 3), conspicuously flattened branches, minutely scabrous surface (Fig. 73: 9) and large, 3-lobed underleaves, which are subequal to the leaves in size (Fig. 73: 3). The branch leaves are widely set, leaving the two dorsal rows of cortical cells broadly exposed (Fig. 73: 5). Telaranea lindenbergii var. complanata of New Zealand has complanate-foliate branches that appear comb-like, a result of the obliquely spreading, incubously oriented branch leaves. The branch leaf insertions, however, approach the midline of the branch, without leaving a conspicuous median strip.
Several other Australasian species of Telaranea have 2–3-lobed, deeply divided leaves. In T. herzogii the leaf “disc” is formed from the cells of the partially connate lobe bases, lacking a tier of disc cells along the insertion. In T. granulata, there is at least one complete tier of disc cells along the insertion, plus the basal cells of the lobes. Telaranea trilobata and T. fragilifolia have similar leaves but produce Microlepidozia -type branches, which are unknown in T. granulata. In addition, the leaf lobes of T. fragilifolia are caducous.
