Trichocoleaceae Nakai
Trichocoleaceae Nakai, in Ogura, Ord. Fam. Trib. Gen. Sect. ... nov. ed. 200. 1943.
Type: Trichocolea Dumort.
Plants often appearing like a mass of interwoven hairs, anisophyllous, usually prostrate, at times pendulous, pale green to yellow-green to pure green, lacking secondary pigments (except Castanoclobos); plants small to robust. Branching for the most part regularly 1–3(4)-pinnate (except Castanoclobos and Leiomitra), the branches nearly exclusively of Frullania type; Acromastigum -type branches rare or sporadic (Leiomitra and Eotrichocolea); intercalary branches lacking. Stems often copiously paraphyllose, the cortex poorly differentiated. Rhizoids absent or rare, sometimes from a unistratose rhizoid pad on the underleaf lamina. Leaves often highly dissected into lobes and cilia, with insertion usually succubous (± transverse to incubous in Eotrichocolea), asymmetric, the ventral lobes larger and the ventral sector of disc higher, deeply (3)4-lobed, but often with numerous secondary, smaller lobes; lobes acute to acuminate, usually narrow, usually armed with often branched, typically opposed cilia, the cells of lobes and cilia elongate; disc usually low, of only a few cells high. Cells of disc elongate-rectangular, often ± in tiers, thin- or weakly firm-walled; surface papillose or striate-papillose. Oil-bodies 4–14 per cell, up to 33 per cell in cilia, spherical and 3.5–6 µm diam. or 3.5–6 × 7–8 µm and irregularly ovoid, or ellipsoidal, grey, finely granular to papillose. Underleaves symmetric, bifid, but the lobes again divided (except Eotrichocolea), often bisbifid, armed as in leaves. Asexual reproduction lacking.
Dioecious. Androecia on leading leafy shoots; bracts concave, basically similar to leaves but with lamina larger and lobes shorter, with 1–2 antheridia, the stalk biseriate (?always); bracteoles without antheridia. Gynoecia on leading leafy shoots in ours (on short, Frullania -type branches in Leiomitrasubg.Brachygyna); bracts and bracteoles similar to leaves and underleaves but larger and more freely lobed. Sporophyte protected by a bulbous to clavate coelocaule densely covered by reduced bracts and paraphyllia, commonly hispid in aspect; perianth completely absent (Trichocolea, Eotrichocolea), or present as a low, deeply lobed remnant (Leiomitra), or well developed, fused to and continuous with a perigynium and invested in hairs (Castanoclobos); calyptra absent or (Leiomitra) present and low, cap-like or bulbous.
Seta of numerous cells, the outermost and internal cells ± similar in size. Capsule ellipsoidal, ovoid or spherical, 3–8-layered, the outer layer of cells hyaline, high, with pigmented wall thickenings absent or sparse; innermost layer of cells with small nodular thickenings, at times with incomplete or complete semiannular bands.
Spores granular or granular asperulate. Elaters sinuous, not tortuous, bispiral or less often 3-spiral or 2–3-spiral.
A family with four genera, all of which occur regionally. It includes some of the most beautiful and intricate of hepatics, including the recently described Castanoclobos.
