The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland

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L. Watson and M. J. Dallwitz

Blepharostoma (Dum. emend Lindb.) Dum.

Gametophyte. Plants leafy. Plants slender, the shoots procumbent to ascending, the stems branching irregularly. The stems with no clear differentiation of cortical and central tissues. Acrogynous. The leaf cells without trigones.

The leafy shoots dorsiventral, with two equal ranks of lateral leaves and a third, ventral rank of smaller underleaves, or more or less dorsiventral, the three-ranked leaves more more less equal in size (the underleaves similar to the laterals, tending to be smaller and 3-lobed). The vegetative leaves transversely inserted to obliquely inserted; overlapping to distant; patent to spreading, when overlapping succubous. The leaf margins in effect, multi-ciliate. The vegetative leaves so deeply divided as to be almost reduced to long, slender, bi- to uniseriate segments (divided almost to the base into 3–4 more or less equal, stiff uniseriate segments, each of 7–13 cells); without vittae. Underleaves similar in size to the laterals. The cells of the gametophyte with numerous small chloroplasts. Gemmae very rare to absent.

The plants dioecious, or bisexual (then monoecious); when monoecious, autoecious, or paroecious.

Male inflorescences on main axes or lateral branches, the male bracts similar to the leaves but less deeply bilobed, the underleaves without antheridia. Female inflorescences terminal. Female bracts present (these free of the perianth, larger than the leaves, 4–5 lobed, and the lobes dichotomously branched). Perianth present; this subcylindrical, unistratose, contracted to its ciliate mouth, the cilia to seven cells long.

Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule ovoid. The capsule wall 2–5 layered. The spores unicellular when shed. Elaters present; bispirally thickened; free.

British representation. 1 species (B. trichophyllum); England, Wales, Scotland, and Ireland.

Classification. Class/Division Hepaticae. Subclass/Class Jungermanniidae. Order Jungermanniales. Family Pseudolepicoleaceae.

Illustrations. • B. trichophylla: Jameson, in Macvicar (1926). • B. trichophylla (as trichophyllum): Pearson fig. XLI (1902). • B. trichophylla (as trichophyllum): Pearson fig. XLI legend.

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Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland. Version: 24th February 2016.’.