The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland
Including Chandonanthus Mitt.
Gametophyte. Plants cushion- or mat-forming, pale yellowish brown, leafy. The slender, brittle, stems procumbent simple or with procumbent or ascending, irregular lateral branching. Plants with flagella or flagelliform shoots or branches (at least, the branch extremities sometimes attenuate and microphyllous), or with neither flagella nor flagelliform shoots or branches. Acrogynous. The leaf cells more or less without trigones. Rhizoids scarce but present (towards stem bases and the apices of microphyllous branches); colourless.
The leafy shoots dorsiventral, with two equal ranks of lateral leaves and a third, ventral rank of smaller underleaves; more or less julaceous. The vegetative leaves more or less more or less symmetrical. The vegetative leaves more or less transversely inserted to obliquely inserted; overlapping (densely imbricate); wider than long, succubous; broader than long and semi-amplexicaul, dentate or spinous-dentate at the base bilobed to several-lobed (but mostly 3–4 lobed from halfway to near the base, the erect lobes blunt, ovate-oblong, channelled, coarsely dentate at their bases); with vittae (being virtually ribbed into the lobes). Underleaves rather smaller than the laterals though well developed and conspicuous (quite large, deeply bilobed). The cells of the gametophyte with numerous small chloroplasts.
The plants dioecious.
Male inflorescences (androecia) intercalary on the main stem, comprising several pairs of bracts resembling the leaves but less deeply lobed. Male bracts subtending 2 antheridia, or several antheridia (2–3). The antheridia mixed with paraphyses. Female inflorescences terminal, but often appearing lateral through innovation. Female bracts present (larger than the leaves, deeply 4-lobed, the lobes lanceolate and long-acuminate). Bracteole present (bilobed to halfway, laciniate-ciliate at the base, the lobes triangular-lanceolate, long-acuminate and basally dentate-ciliate). Perianth present; half exserted beyond the bracts, narrowly ovoid, deeply multi-plicate to the base and slightly contracted at the ciliate mouth. Perianth distally plicate. Calyptra present and well developed (thin, free, surrounded at the base by sterile archegonia).
Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule ovoid; probably dehiscing by four valves. Elaters present; probably bispirally thickened; free.
British representation. 1 species (T. setiformis); England and Scotland.
Classification. Class/Division Hepaticae. Subclass/Class Jungermanniidae. Order Jungermanniales. Family Lophoziaceae.
Illustrations. • T. setiformis (as Chandonanthus): Jameson, in Macvicar (1926). • T. setiformis (as Chandonanthus): Pearson fig. XLII (1902). • T. setiformis (as Chandonanthus): Pearson fig. XLII legend.
To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.
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. delta-intkey.com’.