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| The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland |
Gametophyte. Plants as tufts, patches or scattered individuals, leafy. Procumbent to erect, usually branched from the postical angles of leaves. Acrogynous. The leaf cells commonly with trigones, or without trigones. Rhizoids present; colourless, or colourless and brown (sometimes brown at the base).
The leafy shoots dorsiventral, with the two ranks of laterals more or less equal in size and the ventral rank lacking (nearly always), or dorsiventral, with two equal ranks of lateral leaves and a third, ventral rank of smaller underleaves. The vegetative leaves usually more or less more or less symmetrical. The vegetative leaves more or less transversely inserted to obliquely inserted; alternate; usually more or less overlapping; symmetrical to asymmetrical, decurrent, the ventral margins without cilia, succubous. The leaf margins entire; incurved or inflexed to flat; dorsally decurrent. The vegetative leaves usually bilobed (from only slightly to 1/3, the lobes acute to rounded, the upper sometimes secondarily 3–4 lobed); not complicate-bilobed. The ventral lobes usually more or less similar in size to the dorsal ones. The vegetative leaves the cell walls thick to thin, but without vittae. Underleaves absent (at least from sterile stems). The cells of the gametophyte with numerous small chloroplasts. The chloroplast-containing cells commonly with conspicuous oil bodies (6–50 per cell). Gemmae usually present, common to rare (at apices and margins of upper leaf lobes, 1–2 celled, angular).
The plants dioecious (mostly), or bisexual; when bisexual, having the gametangia grouped into bracteate inflorescences; paroecious.
Male inflorescences (androecia) terminal or intercalary, the 5–8(-15) pairs of bracts basally saccate and often with an antical tooth or lobe. Male bracts subtending a single antheridium to several antheridia (these ovoid to globose). Female inflorescences terminal. Female bracts present (larger than the leaves, 2–5 lobed, dentate or not). Female bracts larger than the (upper) leaves; perianth present; perianth terminal, longly exserted, ovate to cylindical, and shortly contracted at the mouth, not beaked. Perianth usually deeply distally plicate. Perianth not beaked.
Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule longly pedicellate, ovoid to shortly cylindrical; commonly reddish brown, not green. The spores unicellular when shed. Elaters present; bispirally thickened; free.
British representation. About 13 species; England, Wales, Scotland, and Ireland.
Classification. Class/Division Hepaticae. Subclass/Class Jungermanniidae. Order Jungermanniales. Family Lophoziaceae.
Illustrations. • L. bicrenata: Jameson, in Macvicar (1926). • L. bicrenata (as Jungermania): Pearson fig. CXXXIX (1902). • L. bicrenata (as Jungermania): Pearson fig. CXXXIX legend. • L. excisa: Jameson, in Macvicar (1926). • L. excisa (as Jungermania capitata): Pearson fig. CXXXVIII (1902). • L. excisa (as Jungermania capitata): Pearson fig. CXXXVIII legend. • cf. L. excisa forma cylindracea (as Jungermania socia): Pearson fig. CXXXVII (1902). • cf. L. excisa forma cylindracea (as Jungermania socia): Pearson fig. CXXXVII legend. • L. incisa: Jameson, in Macvicar (1926). • L. longidens: Jameson, in Macvicar (1926). • L. longiflora: Jameson, in Macvicar (1926). • L. obtusa: Jameson, in Macvicar (1926). • L. obtusa (as Jungermania): Pearson fig. CXXXVI (1902). • L. obtusa (as Jungermania): Pearson fig. CXXXVI legend. • L. ventricosa: Jameson, in Macvicar (1926). • L. ventricosa (as Jungermania): Pearson fig. CXL (1902). • L. ventricosa (as Jungermania): Pearson fig. CXL legend. • cf. L. ventricosa (as Jungermania vars. porphyroleuca and whiteheadii): Pearson fig. CXLI (1902). • cf. L. ventricosa (as Jungermania vars. porphyroleuca and whiteheadii): Pearson fig. CXLI legend. • L. wenzelii: Jameson, in Macvicar (1926).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland. Version: 5th August 2019. delta-intkey.com’.
