Triandrophyllum symmetricum J.J.Engel
Triandrophyllum symmetricum J.J.Engel, Haussknechtia Beih. 9: 115. f. 1, 2. 1999.
Holotype: New Zealand, North Is., Hawkins Hill, Wellington, 7 Sept. 1981, T. Moss s.n. (AK); isotype (fragment): (F).
Plants erect, pale olive-green, often tinged with rose, particularly at shoot tips, the shoot tips straight and not decurved, consisting of closely imbricate leaves and underleaves, forming a loose capitulum; shoots to 2.4 mm wide. Branches rather common, of ventral- and lateral-intercalary types, originating from median and lower sectors of shoots, becoming erect and leafy or horizontal and stoloniform, the plants with a system of basal, prostrate stolons from which arise upright leafy shoots. Stems with cortex of 1 layer of cells, the exposed cell wall distinctly thickened, the cells somewhat smaller than those of the medulla; medullary cells thin. Leaves rigid, obscurely ventrally secund, obliquely spreading, closely imbricate, the stem hidden dorsally and ventrally, the insertion feebly recurved at dorsal end, the leaves concave, ± symmetric to feebly asymmetrically quadrate to very short-rectangular, about as wide as long (less than 1.1× longer than wide), consistently 3(4)-lobed to 0.45–0.55, 1.2–1.3 mm wide × 1.2–1.4 mm long; lobes subequal or the dorsal larger and the median and ventral lobes subequal in size, slightly to distinctly concave, acute, often apiculate, the tip terminating in a single cell or at most a uniseriate row of 3 thick-walled, at most slightly elongated cells, the lobe margins for the most part entire but occasionally with a tooth; lamina ca. 20–23 cells from dorsal sinus base to leaf base; dorsal margin dilated at the base, ± cordate; dorsal and ventral margins of lamina often with 1(2) appendages at extreme base, the appendages irregular, often laciniiform to lobuliform, often hook-like, the dorsal margin of lamina otherwise entire, the ventral often with 1–4 teeth. Leaf cells with walls somewhat thickened, trigones distinct, medium to large and slightly bulging, median cells of lamina 24–32 µm wide, 36–46 µm long; oil-bodies unknown; leaf surfaces densely striolate-papillose. Underleaves slightly smaller than leaves, obliquely spreading, convex (ventral view), symmetrically subquadrate to broad ovate, consistently 3-lobed to 0.4–0.5; lobes as in leaves except the tip occasionally terminating in 2 laterally juxtaposed cells and the margins more often with a tooth; margins each often with an appendage at extreme base similar to that of leaves, the margins otherwise entire or with a few teeth.
Androecia on main shoot, terminal but eventually becoming intercalary, a little wider than sterile sectors; bracts and bracteoles a little more closely imbricate than leaves and underleaves, in 4–5 pairs; bracts and bracteoles similar to leaves and underleaves except less deeply lobed, the lamina distinctly ventricose, the lamina margins with several coarse teeth; antheridia 3–4 per bract and bracteole, the stalk long (to 17 cells long). Gynoecia on main shoot or leading branches; bracts of innermost series much larger than leaves, erect, ensheathing and conforming to contours of perianth, not or feebly ventrally secund, ± symmetrically ovate, ± symmetrically 3–4-lobed (the dorsal lobe not larger), the lobes slenderly attenuate, entire; dorsal and ventral margins of lamina with to 3 or more coarse teeth, the dorsal margin at times entire, the extreme base of both margins with a conspicuous appendage; bracteoles of innermost series similar to bracts in size, shape and depth of sinuses, the lamina margins with several laciniiform to lobuliform processes. Perianth not demonstrably exserted beyond bracts, short, broadly ovate, distinctly plicate, with several plicae extending to base (at least dorsally), the perianth narrowing to the 9-lobed mouth, the lobes long, slender and often parallel-sided for much of their length, entire or with several teeth or long cilia toward base.
Seta with ca. 60 rows of outer cells surrounding an inner core of scattered, considerably larger cells. Capsule ± spherical, the wall 71–76 µm thick, of 5–6 layers; outer layer of cells ± equal in thickness of ca. 2 of intermediate layers; outer layer of cells subquadrate to short-rectangular, the radial walls with (1)2–3 red-brown, large, nodular thickenings on longitudinal and transverse walls, but with scattered, rather frequent, longitudinal and transverse walls devoid of thickenings, the walls that lack thickenings not in any pattern; innermost layer of cells irregularly elongate-rectangular, the radial walls with somewhat thick, continuous sheets of red-brown wall material, the walls with semiannular bands common and typically complete, narrow, sometimes forked.
Spores 17.3–18.2 µm in diam., reddish brown, with low, sharply defined, close, irregular, short, sometimes furcate, vermiculate ridges and, often, papillae. Elaters straight or feebly tortuous, 9.6–10.1 µm wide, bispiral, the spirals 3.4–3.8 µm wide, rather closely wound, extending to the tips.
Distribution and Ecology : New Zealand: North Island (435 m). Known only from the type, which is from Hawkins Hill (41° 199 S, 174° 449 E), near Wellington, at ± 435 m in a steep-sided stream gully with Hymenophyllum minimum. Plants of this species were not found in a search of this area in 2003.
Comments : This species differs from Triandrophyllum subtrifidum in a number of respects, including aspect, leaf orientation and symmetry. Shoot tips are straight, consisting of closely imbricate leaves and underleaves, and form a loose capitulum. On the other hand, shoot tips of T. subtrifidum are recurved and never form a capitulum. Leaves and underleaves of T. symmetricum are obliquely spreading and are so densely imbricate that the stem is not visible in either dorsal or ventral views (Fig. 14: 1; Fig. 15: 1) vs. leaves and underleaves that are oriented at ± right angles to the stem and distant to approximate so that the stem is nearly always visible at least in ventral aspect in T. subtrifidum (Fig. 16: 1). Leaves of T. symmetricum are 3(rarely 4)-lobed and ± symmetric to at most weakly asymmetric (Fig. 14: 3, 4) vs. 2–3-lobed and distinctly asymmetric in T. subtrifidum (Fig. 16: 3, 4). Also, T. symmetricum has deeper leaf sinuses: 20–23 cells from dorsal sinus base to leaf base vs. 24–34 cells high in T. subtrifidum.
