Archeophylla R.M.Schust.
Archeophylla R.M.Schust., J. Hattori Bot. Lab. 26: 263. 1963.
Type: Archeophylla schusteri (E.A.Hodgs. & Allison) R.M.Schust (≡Temnoma schusteri E.A.Hodgs. & Allison)
Plants moderately to distinctly anisophyllous, creeping or procumbent (ours) to ascending to erect, ± rigid, green to pale brown to yellow-brown. Branching sparing, irregular, the branches nearly always ventral-intercalary; terminal branches present, sporadically of Frullania type, rarely of Microlepidozia type. Stems stiff and wiry, the cortical cells with exposed wall thickened, moderately to distinctly larger than the medullary cells; medullary cells firm-walled, thickened at the angles. Rhizoids frequent, from underleaf cells. Leaves remote, widely spreading (in ours), the insertion transverse to feebly succubous, broadly obcuneate to obtrapezoid, equally 3–4-lobed to (0.55)0.6–0.75(0.8) (never bisbifid); lobes long-acuminate, only 2–4 cells wide at base, tapered distally to a setaceous uniseriate row of 7–13 cells, the lobes entire (rarely with a tooth on trifid leaves); disc 5–7 cells high, the cells at most slightly elongated (at most 2× longer than wide), the margins entire or (ours) at times with a tooth. Cells with walls firm and with trigones somewhat bulging or (ours) markedly nodose, confluent or separated by narrow, thin-walled places; cell surface smooth (ours) or papillose-striolate. Oil-bodies (Schuster, 1966a) (1)2–3(4) per cell, greyish, granular. Underleaves 0.4–0.75× lateral leaves but otherwise similar in form, (2)3–4-lobed, lobes stiff, setaceous, uniseriate throughout or with 1–2 biseriate tiers at base; disc 2–5 cells high. Asexual reproduction absent, or by fragmentation of leaf lobes.
Dioecious. Androecia on leading shoots or ± short Frullania- type branches, distinctly differentiated, compactly spicate, the bracts in only (1)2–4(5) pairs; bracts less deeply lobed than leaves (0.5–0.6), the entire disc strongly ventricose, the lobes setaceous, erect to suberect, the bracts monandrous; bracteoles smaller. Gynoecia terminal on long shoots; bracts in 2–4 series, becoming gradually larger but the innermost series usually smaller; bracts of innermost series variable, erect and sheathing base of perianth, 3–4-fid to 0.35–0.55; lobes slenderly acuminate-setaceous, not or at most weakly divergent, entire or with 1–3(4) non-opposed spinose teeth toward base (the teeth only occasionally opposed in Archeophylla pungens); bracteoles similar to bracts but smaller. Perianth long-exserted, lacking a coelocaule-precursor at base, terete below, distinctly 3-plicate in distal 0.25–0.65, contracted to the mouth; mouth lobulate-ciliate, the cilia stiff, bristle-like, long, crowded.
Capsule ovoid, the wall 3–4-layered; outer layer of cells high, with small, remote, nodular thickenings (in Archeophylla pungens) only in cells adjacent to valve margins; innermost layer with nodular to spine-like thickenings (occasionally tangentially extended into local complete semiannular bands in A. pungens).
Spores finely to coarsely papillose. Elaters strongly tortuous, short, the tips strongly and abruptly attenuated, unispiral, the spiral exceptionally wide (7–10 µm).
The genus includes only our species, the generic type and two from southern South America, Archeophylla pungens (Herzog) R.M.Schust. and A. paradoxa R.M.Schust.
References: Schuster (1966a, rev.; 2000a).
Treatment of genus adapted, with considerable modification, from Schuster (1966a).
