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

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L. Watson and M. J. Dallwitz

Metzgeria Raddi

Gametophyte. Plants thalloid, not leafy (the thallus linear, with the midrib sharply defined from the unistratose wings, hairs absent from the dorsal surface and sparse or absent ventrally). Anacrogynous (borne ventrally on the midrib, on dwarf fertile branches which sometimes continue as vegetative branches). Rhizoids of one kind, all smooth.

The cells of the gametophyte with numerous small chloroplasts. The thallus branching dichotomously (and also venrally from the midrib); not hairy both dorsally and ventrally; with a conspicuous median conducting strand; without ventral scales.

The plants dioecious, or bisexual (then monoecious).

The gametangia and capsules borne externally. The archegonia and sporophytes without a pseudoperianth. Calyptra present and well developed (pyriform, becoming fleshy, hairy).

Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule dehiscing by four valves. Elaters present; unispirally thickened; persistent on elaterophores, or free and persistent on elaterophores (?). The elaterophores apical (the elaterophore comprising an indistinct apical thickening of the capsule wall, which on dehiscence splits into four, resulting in an erect tuft of elaters at each of the valve apices).

British representation. 5 species; England, Wales, Scotland, and Ireland.

Classification. Class/Division Hepaticae. Subclass/Class Jungermanniidae. Order Metzgeriales. Family Metzgeriaceae.

Comments. The thallus without dorsal hairs. Illustrations. • M. conjugata: Jameson, in Macvicar (1926). • M. conjugata and M. leptoneura (as hamata): Pearson fig. CCVII (1902). • M. conjugata and M. leptoneura (as hamata): Pearson fig. CCVII legend. • M. furcata: Jameson, in Macvicar (1926). • M. furcata: Pearson fig. CCVI (1902). • M. furcata: Pearson fig. CCVI legend. • M. leptoneura (as hamata): Jameson, in Macvicar (1926).

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.’.