Triandrophyllum Fulford & Hatcher
Type: Triandrophyllum subtrifidum (Hook.f. & Taylor) Fulford & Taylor (≡Jungermannia subtrifida Hook.f. & Taylor)
Plants strongly ascending to erect, the shoot tips straight or (often) decurved, olive-green to brown to yellow-brown, the tips at times tinged with magenta or rose, the plants medium in size. Branches rather common, irregular, 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; Frullania -type branches rare. Stems with cortex 1(2) layers of moderately thick-walled cells about the same size as or somewhat smaller than those of the medulla; medullary cells thin. Rhizoids mostly on stoloniform branches, originating from leaf and underleaf cells, not from stem cells. Leaves rigid, obliquely spreading, obscurely ventrally secund to more distinctly so, the insertion incubous and feebly recurved at dorsal end, the leaves concave to ± canaliculate, rather asymmetric (± symmetric in Triandrophyllum symmetricum), quadrate to more often ovate to ovate-elliptic, often ± falcate, the dorsal margin longer, more strongly arched, dilated at the ± cordate base, the leaves 2–3(4)-lobed to 0.3–0.55; lobes unequal, the dorsal larger or (T. symmetricum) subequal, the lobes acute to acuminate, often apiculate, entire. Cells with walls firm and for the most part evenly thick-walled, with trigones mostly indistinct and small to at most medium (at times large and slightly bulging in T. symmetricum); surfaces densely striolate-papillose. Oil-bodies (see Schuster, 2000a) finely botryoidal, (1)5–12(15) per cell. Underleaves transversely inserted, slightly to moderately smaller than leaves but never less than 0.55 their size, obliquely spreading to squarrose, symmetrical, for the most part oblong-elliptical to narrowly ovate, at times subquadrate to broad ovate, 2–3(rarely 4)-lobed. Asexual reproduction absent.
Androecia with bracts and bracteoles similar to leaves and underleaves in form but pouched at the base; antheridia 2–4 in each bract and bracteole, the stalk biseriate. Gynoecial bracts of innermost series much larger than leaves but basically similar in form to them except the margins often with stronger teeth; bracteoles of innermost series similar to bracts. Perianth not demonstrably exserted beyond bracts, oblong-ovate to ovate, distinctly plicate in distal half or more, the mouth divided up to 0.5 by 6–9 long and slender lobes, the lobes entire or with several teeth or cilia at the base.
Seta massive, the outer cells in up to 60 rows. Capsule ± spherical, the wall 4–6(7)-layered, the outer layer with nodular thickenings on longitudinal and transverse walls, but with scattered, longitudinal and transverse walls devoid of thickenings, the walls lacking thickenings not in any pattern; inner layer with semiannular bands.
Spores papillose-vermiculate. Elaters bispiral.
Key to Species
The genus Triandrophyllum consists of four species: a) T. subtrifidum, which is amphi-Pacific temperate, occurring on Macquarie Island, New Zealand, Tasmania, the Philippines (Kitagawa, 1981), Tristan da Cunha, South Sandwich Islands, South Georgia, Falkland Islands, southern South America, southeastern Brazil, the Andes and Central America northward to Mexico; b) T. symmetricum (Engel, 1999c) of New Zealand; c) T. fernandeziense (S.W.Arnell) Fulford & Hatcher, emic to Juan Fernandez Islands; and d) T. heterophyllum (Steph.) Grolle of New Guinea and Java. Triandrophyllum georgiense (Steph.) Fulford & Hatcher of South Georgia belongs in the synonymy of T. subtrifidum (see Solari, 1973); the species was accepted by Schuster (2000a). Gradstein (Gradstein et al., 2001) placed Olgantha eophyllum in Triandrophyllum; the species should be maintained in the monotypic Olgantha.
References: Engel (1999c); Fulford (1963b); Fulford and Hatcher (1959); Schuster (2000a); Solari (1973); Stewart (1978; oil-body data of T. subtrifidum).
