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

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L. Watson and M. J. Dallwitz

Herbertus S.F. Gray

Gametophyte. Plants plants large and rigid, reddish brown leafy. The shoots erect or ascnding, often arising from prostrate primary stems. The branching conventional. Plants with flagella or flagelliform shoots or branches (sometimes, these ventral), or with neither flagella nor flagelliform shoots or branches. Acrogynous. The leaf cells with trigones. Rhizoids present (at the bases of erect stems), or absent.

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 vegetative leaves almost transversely inserted to obliquely inserted; alternate; overlapping; incubous; a half to three-quarters bilobed to several-lobed (the lobes long, narrow and acuminate); with vittae (comprising elongated, pitted median cells extending into the lobes). Underleaves resembling and similar in size to the laterals. The cells of the gametophyte with numerous small chloroplasts.

The plants dioecious.

Male inflorescences bud-like, subterminal, wuth saccate bracts less deeply bilobed than the leaves. Female inflorescences bud-like, terminal, the bilobed bracts more or less concealing the perianth. Female bracts present (several, bilobed). Bracteole absent. Perianth present (more or less concealed by the several imbricate bracts); narrow, ovate-subulate, split more or less to halfway into six laciniate lobes.

Sporophyte. The sporophyte terminal, elevated by elongation of the seta, with no intercalary meristem. The capsule globose; dehiscing by four valves (the valves often bipartite). Elaters present; bispirally thickened; free.

British representation. 3 species; England, Wales, Scotland, and Ireland.

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

Illustrations. • H. aduncus ssp. hutchinsiae: Jameson, in Macvicar (1926). • H. aduncus (as Herberta adunca): Pearson fig. XXXVI (1902). • H. aduncus (as Herberta adunca): Pearson fig. XXXVI legend. • cf, H. stramineus (as adunca): 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.’.