The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland
Gametophyte. Plants pale-, yellowish- or dark- or blackish-green tufts or thin patches or mixed with other bryophytes, leafy. The shoots procumbent to ascending, the stems occasionally to frequently, irregularly branched. Acrogynous. The leaf cells thin walled, with trigones (very small), or without trigones. Rhizoids present (in tufts from underleaf bases); colourless.
The leafy shoots dorsiventral, with two equal ranks of lateral leaves and a third, ventral rank of smaller underleaves. The vegetative leaves more or less symmetrical. The vegetative leaves not wedge-shaped; very with J-shaped insertion; alternate; overlapping to distant (to subimbricate); spreading horizontally, the dorsal margins decurrent, succubous. The leaf margins entire. The vegetative leaves oblong to rectangular, undivided (the apices rounded to emarginate); without vittae. Underleaves smaller than the laterals though well developed and conspicuous (much smaller, often with a tooth on one or both sides, 1/2–2/3 lobed, the lobes subulate). The cells of the gametophyte with numerous small chloroplasts. Gemmae rare.
The plants dioecious, or bisexual; when bisexual, having the gametangia grouped into bracteate inflorescences; autoecious.
Male inflorescences intercalary on main stems or long branches, the several pairs of bracts resembling the leaves but with the antheridia in a small, inflexed basal lobe on the dorsal side. Male bracts subtending a single antheridium, or 2 antheridia. Female inflorescences on dwarf ventral branches. Female bracts present (in few pairs, much smaller than the leaves, 2–3 lobed). Bracteole present (smaller than the bracts, bilobed). Perianth present; short, campanulate, the wide mouth deeply 3-lobed. Calyptra present and well developed (large, clavate, extending beyond the perianth and protruding at maturity).
Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule long-pedicellate, ovoid. The capsule wall 4–6 layered. The spores unicellular when shed. Elaters present (reddish-brown); loosely bispirally thickened; free.
British representation. 1 species (C. polyanthos); England, Wales, Scotland, and Ireland.
Classification. Class/Division Hepaticae. Subclass/Class Jungermanniidae. Order Jungermanniales. Family Geocalycaceae.
Illustrations. • C. polyanthos: Jameson, in Macvicar (1926)). • C. polyanthos, var. pallescens: Jameson, in Macvicar (1926)). • C. polyanthos: Pearson fig. CVI (1902). • C. polyanthos: Pearson fig. CVI 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’.