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

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L. Watson and M. J. Dallwitz

Cryptothallus Malmb.

Gametophyte. Plants thalloid, not leafy (subterranean, creamy white, without chlorophyll, prostrate or rarely ascending, the male thalli smaller). Anacrogynous. Rhizoids present; of one kind, all smooth.

The cells of the gametophyte lacking chloroplasts. The thallus irregularly pinnately branching, or simple (or coralloid). Subterranean, under humus, leaf litter, etc.. The thallus without a conspicuous conducting strand (circular, semi-circular or plano-convex in section, the upper cells with starch grains, the lower with endophytic fungal hyphae said to be parasitized by the livewort); without ventral scales. Gemmae absent. The thallus without dorsal pores; without cavities.

The plants dioecious; with no grouping of gametangia into bracteate inflorescences. The antheridia not protected by bracts (on short lateral branches).

The archegonia and sporophytes not protected by bracts. The archegonia and sporophytes without a pseudoperianth. Calyptra present and well developed (cylindrical, fleshy).

Sporophyte. The sporophyte elevated by elongation of the seta, with no intercalary meristem. The capsule shortly cylindrical, or elongate-cylindrical; dehiscing by four valves (dehiscing above or below ground). The spores shed as tetrads. Elaters present; unispirally thickened; persistent on elaterophores. The elaterophores apical (usually exhibiting an undivided elaterophore from the apically coherent tip of the dehiscing capsule).

British representation. 1 species (C. mirabilis); England, Wales, Scotland, and Ireland.

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

Illustrations. • C. mirabilis: Paton (1999).

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.’.