| | The liverwort genera (Bryophyta: Hepaticae and Anthocerotae) of Britain and Ireland |
Gametophyte. Plants small or minute, leafy. Shoots usually procumbent, never dichotomous, branching irregularly laterally or ventrally. The stems with cortical cells clearly differentiated from the cells of the central strand, or with no clear differentiation of cortical and central tissues (the cortical cells of similar size to the central cells, but sometimes more heavily thickened). Plants with neither flagella nor flagelliform shoots or branches. Acrogynous. The leaf cells thin- to very thick-walled, extensively illustrated without trigones. Rhizoids present.
The leafy shoots dorsiventral, with two equal ranks of lateral leaves and a third, ventral rank of smaller underleaves, or dorsiventral, with the two ranks of laterals more or less equal in size and the ventral rank lacking. The vegetative leaves transversely inserted to obliquely inserted; alternate; overlapping, or distant; when determinable, succubous; bilobed (from halfway ro near the base, the margins entire to spinose-dentate); without vittae. Underleaves smaller than the laterals though well developed and conspicuous, or present but much reduced or vestigial, or absent (small, very small, or lacking). The cells of the gametophyte with numerous small chloroplasts. The chloroplast-containing cells with conspicuous oil bodies (3–9 per cell). Gemmae common to rare (on tips of leaf lobes at stem apices, (1-)2-celled, vatiously smooth, angular or coarsely papillose), or absent.
The plants dioecious, or bisexual; when bisexual, having the gametangia grouped into bracteate inflorescences; when bisexual, autoecious, or paroecious.
Male inflorescences variously comprising short branches, terminating longer ones or intercalary. Male bracts subtending a single antheridium. Female inflorescences terminating stems or branches. Perigynium absent or vestigial. Female bracts present (1-several pairs increasing in size up the stem, bilobed, the margins entire to spinose-dentate). Bracteole present (similar to the bracts in size, often connate with them for part or all of its length). Perianth present. Perianth usually distally plicate (4–5 plicate).
Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule ovoid (its pedicel ‘composed externally of four rows of cells’). The capsule wall 2 layered. Elaters apparently absent (judging from available descriptions and illustrations ...).
British representation. 13 species; England, Wales, Scotland, and Ireland.
Classification. Class/Division Hepaticae. Subclass/Class Jungermanniidae. Order Jungermanniales. Family Cephaloziellaceae.
Illustrations. • C. baumgartneri: Jameson, in Macvicar (1926). • C. calyculata: Jameson, in Macvicar (1926). • C. divaricata (as starkii): Jameson, in Macvicar (1926). • cf. C. divaricata (as Cephalozia): Pearson fig. LXVII (1902). • cf. C. divaricata (as Cephalozia): Pearson fig. LXVII legend. • C. dentata (as Cephalozia): Pearson fig. LXXIII (1902). • C. dentata: Pearson fig. LXXII legend. • C. elachista: Jameson, in Macvicar (1926). • C. elachista (as Cephalozia): Pearson fig. LXXI (1902). • C. elachista (as Cephalozia): Pearson fig. LXXI legend. • C. hampeana: Jameson, in Macvicar (1926). • C. integerrima: Jameson, in Macvicar (1926). • C. massalongi: Jameson, in Macvicar (1926). • C. massalongi var. aeraria (as Cephalozia aeraria): Pearson fig. LXIX (1902). • C. massalongi var. aeraria (as Cephalozia aeraria): Pearson fig. LXIX legend. • C. nicholsonii: Jameson, in Macvicar (1926). • C. rubella: Jameson, in Macvicar (1926). • C. rubella (as myriantha): Jameson, in Macvicar (1926). • cf. C. rubella (as Cephalozia jackii): Pearson fig. LXX (1902). • cf. C. rubella (as Cephalozia jackii): Pearson fig. LXX legend. • C. spinigera (as striatula): Jameson, in Macvicar (1926). • cf. C. stellulifera (as Cephalozia): Pearson fig. LXVIII (1902). • cf. C. stellulifera (as Cephalozia): Pearson fig. LXVIII legend. • C. turneri: Jameson, in Macvicar (1926). • C. turneri (as Prionolobus): Pearson fig. LXXIV (1902). • C. turneri (as Prionolobus): Pearson fig. LXXIV legend.
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’.
