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

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L. Watson and M. J. Dallwitz

Fossombronia Raddi

Gametophyte. Plants fagile, creeping, leafy (the stems flattened above and strongly arched below). Anacrogynous. Rhizoids present; long, attaching the plants firmly to the substrate, apart from the ascending apices violet or purple; of one kind, all smooth.

The leafy shoots dorsiventral, with the two ranks of laterals more or less equal in size and the ventral rank lacking. The vegetative leaves very obliquely inserted; more or less alternate; more or less quadrate to wider than long, succubous; undivided to several-lobed (the margins usually sinuous or lobed, very deeply so in F. fimbriata); without vittae (two cells thick at the base, otherwise unistratose). The cells of the gametophyte with numerous small chloroplasts.

The plants dioecious, or bisexual (then monoecious); when bisexual, having the gametangia grouped into bracteate inflorescences; autoecious, or paroecious. The antheridia protected by bracts, or not protected by bracts.

The archegonia and sporophytes not protected by bracts. The archegonia and sporophytes with a pseudoperianth (this campanulate, often plicate, wide and usually sinuose- or lobed-mouthed). Female bracts absent. Bracteole absent. Perianth absent. Calyptra present and well developed (this pyriform, tender, thick at the base, and shorter than the pseudoperianth).

Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule shortly pedicellate, globose. The capsule wall (2–)4 layered (the inner layer with frequently incomplete annular thickenings). The capsule imperfectly dehiscing by four valves, or dehiscing irregularly. Elaters present; bispirally thickened, or thickend via 3–4 spirals; free.

British representation. 9 species; England, Wales, Scotland, and Ireland.

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

Comments. The gametangia located on the upper surface of the stems, towards the apices; the orange-yellow antheridia naked or protected by bracts, the archegonia naked at first, the fertilized one always near the apex and becoming protected by a pseudoperianth. Illustrations. • F. angulosa: Pearson fig. CLXXXV (1902). • F. angulosa: Pearson fig. CLXXXV legend. • F. caespitiformis: Jameson, in Macvicar (1926). • F. caespitiformis: Pearson fig. CLXXXVII (1902). • F. caespitiformis: Pearson fig. CLXXXVII legend. • F. foveolata (as dumortieri): Pearson fig. CLXXXVI (1902). • legCLXXXVI.jpg<@subject. • F.. • foveolata. • (as. • dumortieri):. • Pearson. • fig.. • CLXXXVI. • legend>. • F. pusilla: Jameson, in Macvicar (1926). • F. pusilla: Pearson fig. CLXXXIII (1902). • F. pusilla: Pearson fig. CLXXXIII legend. • F. wondraczeki (as cristata): Pearson fig. CLXXXIV (1902). • F. wondraczekii (as cristata): Pearson fig. CLXXXIV legend. • cf. F. wondraczekii as F. mittenii): Pearson fig. CLXXXVIII (1902). • cf. F. wondraczekii as F. mittenii): Pearson fig. CLXXXVIII legend. • 4 Fossombronia spp., spores and elaters: Jameson, in Macvicar (1926). • F. crozalsii, spore and elater: 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.’.