Blepharidophyllaceae (R.M.Schust.)
Scapaniaceae subfam. Blepharidophylloideae R.M.Schust., Hepat. Anthocerotae N. Amer. 3: 175. 1974.
Blepharidophyllaceae (R.M.Schust.) R.M.Schust. in G.C.S.Clarke & Duckett, Syst. Assoc. Spec. 14: 74. 1980, nom. inval.; (R.M.Schust.) R.M.Schust. ex J.J.Engel, Fieldiana, Bot. N.S. 25: 108. 1990.
Type: Blepharidophyllum Ångstr.
Plants prostrate to erect, light green in shade forms, but with direct light becoming yellowish brown or red-brown to deep brown or (Clandarium xiphophyllum) vinaceous. Branching sparing, irregular, predominantly Frullania type; Radula type present in some species; ventral-intercalary branches also present. Stems with cortex undifferentiated, in 1–2 layers of thin- to rather thick-walled, often brownish cells averaging slightly or distinctly smaller than medullary cells; mycorrhizal infection lacking. Rhizoids usually rarely produced, in fascicles from ventral leaf bases. Leaves fundamentally bisbifid, complicate-bilobed, the keel well defined (Clandarium) or the juncture of dorsal and ventral lobes U-shaped in cross section (Blepharidophyllum), the leaf insertion nearly transverse or on a U- or V-shaped open arc, extending dorsally to stem midline; lobes equal or the dorsal moderately smaller, with apices shallowly bilobed or bidentate (retuse to rounded in B. densifolium), the lobe margins variously dentate to ciliate. Cells thin-walled and with nodose trigones (Blepharidophyllum) or thick-walled and lacking trigones (Clandarium). Oil-bodies dull-opaque, 2 in nearly all cells of lobes, obscurely granular or obscurely finely papillose. Underleaves absent, except when associated with gemma formation (Clandarium). Asexual reproduction lacking or (Clandarium) via gemmae, the gemmae 2-celled, ovoid, formed in branched, catenated masses from apices of leaf lobes and from lobes of underleaves.
Dioecious. Androecia hardly differentiated; bracts similar to leaves, somewhat ventricose, without a dorsal tooth or lobe; antheridia 2–4 per bract, the body ellipsoid, the stalk 2-seriate. Gynoecia never innovating if fertilized, rarely with a ventral-intercalary innovation if unfertilized; bracts similar to leaves but usually with margins more copiously armed, bilobed like the leaves, with each lobe shallowly bifid. Perianth fusiform, ± dorsiventrally flattened, plicate distally, gradually narrowed toward the mouth, the mouth narrow, ± bilabiate, variously (often strongly) ciliate; perianth polystratose toward base. Sporophyte (known in mature state only for B. densifolium). Foot with a conspicuous haustorial, beet-shaped collar, only the collar penetrating tip of shoot. Seta very long, massive, of undifferentiated cells, the outer layer of cells in ca. 30 rows. Capsule long-ovoid to ovoid-cylindrical, the wall 5–6-stratose; outer layer of cells with one-phase ontogeny, the cells with nodular (I-shaped) thickenings on radial walls; innermost layer of cells with semiannular bands.
Spores ca. 16–20 µm in diam., granular. Elaters ca. 8–10 µm wide, bispiral.
A family of two genera, both strictly Austral in distribution. Blepharidophyllum has two species, one, B. densifolium, is amphi-Atlantic temperate, occurring in South Georgia, the Falkland Islands, southern South America, Kerguelen Island, Crozet, Marion and Prince Edward islands and Gough Island, and the other is found in our area. Clandarium has three species, one in our area, while C. clandestinum is amphi-Atlantic temperate, found in the Falkland Islands, southern South America and Kerguelen Island, and C. gottscheanum occurs in the Falkland Islands and southern South America.
Descriptions of family and the two genera after Schuster (2002a) but heavily modified.