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

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L. Watson and M. J. Dallwitz

Jungermannia L.

Including Aplozia Dum., Eucalyx Breidl.

Gametophyte. Plants small to large, yellowish-green to brown, leafy. Shoots prostrate to erect, branches arising laterally, innovations arising under the perianth. Acrogynous. The leaf cells with trigones, or without trigones. Rhizoids usually present (generally abundant); colourless, or violet or purple, or brown.

The leafy shoots dorsiventral, with the two ranks of laterals more or less equal in size and the ventral rank lacking. The vegetative leaves obliquely inserted; alternate; usually more or less overlapping; reniform, ovate, orbicular or elliptical, succubous. The leaf margins entire; dorsally decurrent (and sometimes decurrent on both sides), or not or only slightly dorsally decurrent. The vegetative leaves undivided; without vittae. The cells of the gametophyte with numerous small chloroplasts. Gemmae usually absent.

The plants dioecious, or bisexual; when bisexual, having the gametangia grouped into bracteate inflorescences; when bisexual, paroecious.

Male inflorescences when dioecious, terminal prior to becoming intercalary, the bracts of similar shape to the leaves, basally saccate. Female inflorescences terminal. Perigynium present and well developed (short, or long and bearing 1–2 pairs of female bracts), or absent or vestigial. Female bracts present (entire and shaped similarly to the leaves). Bracteole absent. Perianth present; concealed to 2/3 emergent, variously shortly cylidrical, obovoid, clavate or fusiform, gradually or abruptly contracted to the mouth and sometimes beaked. Perianth distally plicate (usually), or distally smooth, not plicate. Perianth distally beaked, or not beaked.

Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule wall 2 layered. The spores unicellular when shed. Elaters present (usually reddish brown); bispirally thickened; presumably free (!).

British representation. 14 species; England, Wales, Scotland, and Ireland.

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

Comments. Alarming nomenclatural confusion post-Macvicar, cf. (e.g.) his Aplozia and Eucalyx. Illustrations. • J. atrovirens (as Aplozia): Jameson, in Macvicar (1926). • J. atrovirens (as J. riparia): Pearson fig. CXXIV (1902). • J. atrovirens (as J. riparia): Pearson fig. CXXIV legend. • J. caespiticia (as Aplozia): Jameson, in Macvicar (1926). • pears122.gif. • legCXXII.jpg. • J. gracillima (as J. crenulata): Pearson fig. CXXVII (1902). • J. gracillima (as J. crenulata): Pearson fig. CXXVII legend. • J. gracillima (as J. crenulata var. gracillima): Pearson fig. CXXVIII (1902). • J. gracillima (as J. crenulata var. gracillima): Pearson fig. CXXVIII legend. • J. hyalina (as Nardia hyalina): Pearson fig. CLVIII (1902). • J. hyalina (as Nardia hyalina): Pearson fig. CLVIII legend. • J. leiantha (as Aplozia lanceolata): Jameson, in Macvicar (1926). • J. leiantha (as Liochlaena lanceolata): Pearson fig. 120 (1902). • J. leiantha (as Liochlaena lanceolata): Pearson fig. 120 (1902). • J. obovata (as Nardia obovata): Pearson fig. CLIX (1902). • J. obovata (as Nardia obovata): Pearson fig. CLIX (legend. • J. pumila (as Aplozia): Jameson, in Macvicar (1926). • J. pumila: Pearson fig. CXXIII (1902). • J. pumila: Pearson fig. CXXIII legend. • J. sphaerocarpa (as Aplozia): Jameson, in Macvicar (1926). • J. sphaerocarpa: Pearson fig. CXXV (1902). • J. sphaerocarpa: Pearson fig. CXXV legend). • cf. J. sphaerocarpa (as var. lurida): Pearson fig. CXXVI (1902). • cf. J. sphaerocarpa (as var. lurida): Pearson fig. CXXVI legend.


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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’.

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