The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland
Gametophyte. Plants thalloid, not leafy. Anacrogynous (at least, the 2–3 cm stalked female receptacles nit terminal). Rhizoids of two kinds, smooth and tuberculate.
The cells of the gametophyte with numerous small chloroplasts. The thallus irregularly branching dichotomously; without a conspicuous conducting strand; with ventral scales (sparse, in one row on either side of the midrib, hyaline and elogate, one margin toothed and with a round appendage); usually with gemma-receptacles on the surface (except sometimes in wet habitats). The gemma receptacles semi-lunar with entire margins. The thallus with conspicuous dorsal pores. The pores elevated, simple (surrounded by 3–4 concentric rings of thin walled cells). The thallus containing conspicuous cavities. The air chambers in a single layer in section. The ventral surface pale green.
The plants dioecious.
The gametangia and capsules borne externally. The archegonia and sporophytes not protected by bracts. The archegonia and sporophytes without a pseudoperianth. The gametangia borne on special receptacles. The female receptacles stalked; cruciately 4-rayed. The male receptacles sessile.
Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule dehiscing by four valves. Elaters present; bispirally thickened; threadlike, free.
British representation. 1 species (L. cruciata); England, Wales, Scotland, and Ireland.
Classification. Class/Division Hepaticae. Subclass/Class Marchantiidae. Order Marchantiales. Family Lunulariaceae.
Illustrations. • L. cruciata: Jameson, in Macvicar (1926). • L. cruciata: Pearson fig. CCXII (1902). • L. cruciata: Pearson fig. CCXII 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’.