The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland
Gametophyte. Plants small to medium sized, dull or pale green or cream, leafy. The stems 1–2 pinnate. The branching conventional. The stems with no clear differentiation of cortical and central tissues. Plants with flagella or flagelliform shoots or branches (sometimes, arising ventrally from the stems, or via attenuation of branch tips), or with neither flagella nor flagelliform shoots or branches. Acrogynous. The leaf cells without trigones.
The leafy shoots dorsiventral, with two equal ranks of lateral leaves and a third, ventral rank of smaller underleaves. The vegetative leaves markedly asymmetrical. The vegetative leaves obliquely inserted; overlapping, or distant; incubous; 1/4 to 3/4 bilobed to several-lobed (the 2–5 lobes 4–12 cells wide towards their bases); without vittae. Underleaves smaller than the laterals though well developed and conspicuous (and more or less symmetrical). The cells of the gametophyte with numerous small chloroplasts. Gemmae absent (or unknown).
The plants dioecious, or bisexual; when bisexual, having the gametangia grouped into bracteate inflorescences; autoecious.
Male inflorescences on short ventral branches, or terminal on attenuated branches, with 4–10 pairs of convave, 2–3 lobed bracts smaller than or similarly sized to the leaves. Male bracts subtending a single antheridium, or a single antheridium to 2 antheridia. The antheridial stalks 2 seriate. Female inflorescences on short ventral branches. Female bracts present (much larger than the leaves, apically entire or toothed). Perianth present; 2–4 stratose.
Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule wall 3–5 layered. The spores unicellular when shed. Elaters present; slender, bispirally thickened; free.
British representation. 3 species; England, Wales, Scotland, and Ireland.
Classification. Class/Division Hepaticae. Subclass/Class Jungermanniidae. Order Jungermanniales. Family Lepidoziaceae.
Illustrations. • L. cupressinae: Jameson, in Macvicar (1926). • L. cupressina: Pearson leg. XLIII (1902). • L. cupressina: Pearson leg. XLIII legend. • L. pearsonii: Jameson, in Macvicar (1926). • L. pearsonii (as pearsoni): Pearson fig. XLV (1902). • L. pearsonii (as pearsoni): Pearson fig. XLV legend. • L. reptans: Jameson, in Macvicar (1926). • L. reptans: Pearson fig. XLIV (1902). • L. reptans: Pearson fig. XLIV 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’.