The Lycopodiales of the British Isles (Isoetes, Lycopodium, Selaginella)
Morphology. Stems elongated, with numerous small leaves; suberect, and rooting at the base only (decumbent only basally); 5–25 cm long; overtly dichotomising vegetatively; without secondary thickening. Leaves eligulate; 4–8 mm long; not hair-pointed.
Homosporous. Sporophylls resembling the foliage leaves; in fertile zones tending to alternate with sterile zones along the stems, rather than in well defined terminal cones. The sporangia basal and subsessile on the adaxial surfaces of the sporophylls, non-septate.
Ecology and distribution. Lowland, upland and montane; heaths, moors, mountain grasslands, rock ledges and mountain tops, ascending to about 1500 m. Throughout the British Isles, common in mountains but rare and decreasing in lowland regions.
Comments. The megaspores are non-functional, reproduction being via bud-like gemmae produced in the leaf axils.
Classification. Family Lycopodiaceae.
Ilustrations. • H. selago (Sowerby and Johnson, 1859). • H. selago: Eng. Bot. 1830 (1886). • British Lycopods: Sowerby and Johnson (1863).
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. 2007 onwards. The Lycopodiales of the British Isles (Isoetes, Lycopodium, Selaginella). Version: 1st September 2009. http://delta-intkey.com’.