Lycopodium clavatum

Øllgaard, Benjamin, Kessler, Michael & Smith, Alan R., 2018, Prodromus of a fern flora for Bolivia. II. Lycopodiaceae, Phytotaxa 334 (3), pp. 255-294 : 262

Lycopodium clavatum L., Sp. Pl. 2: 1101. 1753. ( Fig. 2C–D )

Range: —Almost cosmopolitan, found in humid temperate and boreal regions of the northern hemisphere, and on tropical mountains of the Old and New Worlds; absent from Australia. In Bolivia recorded in CH, CO, LP, and SC.

Ecology: —Common; terrestrial and rupestral, trailing or scrambling in open and usually humid places such as road cuts, roadsides, rock crevices, trail margins, often in pioneer habitats; ca. 600–3700 m.

Notes: — Lycopodium clavatum is highly variable and adaptive to external factors. It exhibits an apparently continuous series of forms, from amply branched plants with diverging branches and spreading, soft leaves, and long, branched peduncles, growing in moist, warm, relatively sheltered habitats, to small, compact, parallel-branched plants with more imbricate and firm leaves, and without, or with short, simple or once-forked peduncles. Forms growing in cold, exposed habitats are here recognized as subsp. contiguum ; similar monostachyous forms are found in the Arctic. The two subspecies recognized here are often considered to be distinct species. However, there are many intermediate forms that we are unable to place in one or the other form with certainty. These intermediates form normal spores and have normal meioses. Because the two forms are usually recognizable and are ecologically rather well defined, we treat them as subspecies.

Figures

FIGURE 2. A, Diphasiastrum thyoides, branchlets, left: upper side, right: lower side (Holm-Nielsen et al. 4818, Ecuador, AAU).—B, Diphasium jussiaei, branchlets, left: upper side, right: lower side (Holm-Nielsen et al. 4670, Ecuador, AAU).—C, Lycopodium clavatum ssp. clavatum growth habit, C1, leaf, C2, subpeltate sporophyll (Harling 4091, Ecuador, S). Ecuador.—D, Lycopodium clavatum ssp. contiguum, growth habit, D1, sporophylls (Cazalet & Pennington 5409, Ecuador, US).