Lycopodiella Holub (1964: 22)

Øllgaard, Benjamin, 2020, Lycopodiaceae in Colombia: Subfamilies Lycopodioideae and Lycopodielloideae, Phytotaxa 433 (3), pp. 195-224 : 205

Lycopodiella Holub (1964: 22) s. str. Type:— Lycopodiella inundata (L.) Holub (= Lycopodium inundatum L.).

Lycopodium subgen. Rhopalostachya Pritzel sect. Inundata Pritzel (1901: 601) .— Lycopodium subgen. Inundatistachys Herter (1909: 29) .— Lycopodium subgen. Lycopodiella (Holub) Øllgaard (1979: 49) .

Sporophytes with prostrate or looping, rooting, indeterminate stems, isophyllous to slightly anisophyllous, horizontally branching shoots, and dorsally arising, erect, simple (or to three times forked [ Brazil]) strobiliferous branches; leaves of erect branches conform with leaves of prostrate shoots, or somewhat reduced; sporophylls arranged in alternating whorls of 5 or more, forming 10 or more longitudinal ranks, free, not enclosing the sporangia in cavities at maturity, subpeltate, with triangular cross-section of the immature stalk; sporangia axillary, transversely oblong, with a narrow stalk, anisovalvate; sidewalls of sporangium wall cells not lignified, straight, with semiannular, lignified thickenings. Spores rugate, with a distinct equatorial rim.

Northern temperate regions, Tropical America south to Northern Argentina. Twelve or more species. Several interspecific hybrids are known in North America, where the hybrids between homoploid species form normal spores (Bruce 1975). The sporophylls of Lycopodiella have been repeatedly indicated to be similar to the leaves, and the genus was therefore assumed to be more primitive than those of the other strobiliferous groups (e.g. Pritzel 1901). Their similarity is only superficial, however. The sporophylls have a distinctly subpeltate base, containing a welldeveloped basal mucilage canal ( Bruce 1976).

The South American representatives of the genus were earlier referred to Lycopodiella alopecuroides (L.) Holub, but this species sensu stricto is limited to North America and Cuba.