Lepidozia bidens J.J.Engel
Lepidozia bidens J.J.Engel in J.J.Engel & R.M.Schust., Fieldiana, Bot. N.S. 42: 79. f. 30. 2001.
Holotype: New Zealand, South Is., Nelson/Westland Prov. boundary, Paparoa Ra., S side of Pororari River, upriver from gorge and ca. 500 m WSW of ford on inland track to Bullock Creek, 10–20 m, Engel 19204 – c. per. (F); isotype: (CHR).
Plants procumbent, in thin mats, slender, flexuous, with spreading branches, pale green, nitid, delicately spinescent when dry, the shoots small to medium, to 1.5 cm wide (stem to branch extremities). Branching exclusively of Frullania type, regularly pinnate, the branches slender, short to greatly elongated and distinctly whip-like, long-flagelliform, microphyllous; secondary branches sporadic to occasional; branch half-leaf symmetric, linear (at times slightly broadening toward base), 2(rarely 3)-lobed to 0.3–0.45; first branch underleaf (2)3–4-lobed, inserted on ventral side of branch base or at juncture of branch and main axis, aligned with branch underleaves. Ventral-intercalary branches not seen. Leaves when dry slightly concave, with the tips of the lobes straight to slightly and broadly incurved; leaves when moist spreading, slightly concave, contiguous to distant, with much of stem exposed in dorsal aspect, 0.45–0.5 × 0.35–0.5 mm, the insertion subtransverse to weakly incubous; leaves distinctly asymmetric, unequally 4(5)-lobed, divided to ca. 0.5–0.65 (median sinus), the distance from dorsal sinus base to insertion much greater than that from ventral sinus to insertion. Lobes long and narrowly attenuate (the dorsal lobes especially so), the dorsal lobes parallel to somewhat divergent (rarely approaching 90°), ± distinctly paired, 3–5 cells wide at base, the ventral lobes often shorter, curved and spreading (often at right angles to the dorsal margin), the lobes terminating in a uniseriate row of 2–3 cells; cells of lobes and uniseriate row somewhat elongated (up to 2:1, but the terminal 1–2 cells sometimes subquadrate), evenly thick-walled; surface of lobes smooth to faintly striate-papillose. Disc strongly asymmetric, subdeltoid, 8–10 cells high at dorsal sinus, 4–5 cells high at ventral sinus, the margins entire, the dorsal margin straight (at most feebly ampliate). Cells of disc-middle moderately and evenly thick-walled, ± longitudinally elongated, particularly those in the dorsal half of leaf, 18–31 µm wide × 30–50 µm long; median basal cells distinctly larger, in 1 to several rows; marginal cells of disc and lobes with a thickened outer wall; surface of disc smooth to faintly striate-papillose. Underleaves inserted on 8 rows of stem cells, small, ca. 1–1.1× stem width, plane, strongly spreading to squarrose, symmetrically quadrifid to ca. 0.4–0.5, the lobes attenuate, ending in a single cell or a uniseriate row of 2–3 cells, the cells of uniseriate row often elongated; disc 4–6 cells high at median sinus; disc margins entire.
Plants dioecious. Androecia not seen. Gynoecia on abbreviated ventral-intercalary branches issuing from main stem; bracts of innermost series deeply concave, narrowly ovate to suborbicular; apices with 2–4 short, irregular lobes, the lobes crenate-denticulate to spinose-dentate; lamina margin bordered by cells of variable shape, the apical or free end of marginal cells variously divergent and forming a short projection or a tooth, the margin irregularly crenate-denticulate to the base; bracteole similar in size and form. Perianth long and prominent, slenderly cylindrical-fusiform, slightly curved, terete below, obscurely trigonous above, distinctly and deeply 3-plicate toward mouth, the perianth gradually narrowing toward the strongly contracted, shallowly 3-lobed mouth; mouth cells thick-walled, especially at the summit, at the apical end laterally free for varying lengths, the mouth thus crenate-denticulate.
Sporophyte not seen.
Distribution and Ecology : Endemic to New Zealand: South Island (35–330 m), North Island (ca. 400–920 m). Known from Otago (Dunedin), Westland, Western Nelson, Volcanic Plateau, Taranaki and Gisborne EPs.
A forest plant of both South and North islands. In the South Island it occurs in wet, rich, lower-elevation forests (0–330 m) in banks of bryophytes or it may be corticolous (on, for example, Fuchsia). It also may occur in open forests (again, below 330 m) of, for example, Nothofagus fusca and Dacrydium cupressinum, and here occurs in large masses at tree bases. In the North Island it occurs, for example, on rotted, decorticated, bryophyte-covered logs in the mature podocarp forest at Whirinaki Forest Park. The species reaches higher elevations in the North Island, occurring on bryophyte-covered wood in Nothofagus – Dacrydium cupressinum – Podocarpus totara forests at Waikareiti Track (Urewera Natl. Park, 920 m), and at Waipai Swamp (also Urewera Natl. Park, 720 m) on the sides of old Sphagnum mounds in a low, open, boggy area with Sphagnum hummocks, Leptospermum scoparium and Dracophyllum subulatum.
Comments : The species may be immediately distinguished by the distinctly paired, long, narrowly attenuate, dorsal lobes which lend a delicately spinescent appearance to dried plants (Fig. 43: 3–5). Related to this feature is the distinctive appearance of the half-leaves, which are linear and deeply divided (up to 0.5) (Fig. 43: 12, 13). The ventral lobes are typically shorter than the dorsal, curved and spreading, often at nearly right angles to the dorsal margin (Fig. 43: 2, 3). The species also has distinctive areolation: median cells of the disc are often elongated, particularly in the dorsal half of the leaf, and the median basal cells are larger in contrast to those along the dorsal and ventral margins (Fig. 43: 3).
Lepidozia bidens belongs to a complex of small to minute species that includes L. novae-zelandiae, L. acantha and L. laevifolia, but differs from all three in its regularly pinnate branching (Fig. 43: 14, 15) and generally larger size.
