Phlegmariurus Holub,

Øllgaard, Benjamin & Testo, Weston, 2021, The Lycopodiaceae of Panamá, Phytotaxa 526 (1), pp. 1-66 : 5

Phlegmariurus Holub, Preslia 36: 21. 1964.

— Type: Phlegmariurus phlegmaria (L.) Holub (= Lycopodium phlegmaria L., Sp. Pl. 2: 1101).

Plants epiphytic or terrestrial, pendulous, recurved, erect, or ascending, isotomously branched throughout (Panamanian species). Roots arising from the stem stele, descending through the cortex to the stem base, here emerging as one basal tuft, or, in heteroblastic species emerging along the underside of prostrate shoots. Shoots homophyllous or gradually to abruptly heterophyllous, the constriction of distal divisions of heterophyllous species associated or not with presence of sporangia. Sporophylls and vegetative leaves alike or sporophylls shorter, not peltate, persisting and green after sporangium dehiscence. Sporangia axillary, reniform, isovalvate, with a short slender stalk; sidewalls of sporangium epidermis cells sinuate, thickened and lignified together with the inner walls. Spores foveolate or fossulate. Gametophytes usually subterranean or deep in epiphytic substrate, mycorrhizal, cylindrical with radial or bilateral symmetry, with pluricellular, uniseriate hairs among the gametangia.

The genus Phlegmariurus is pantropical, with few temperate species, and has perhaps 250 species worldwide, with 31 species known from Panamá. Species diversity worldwide is highest throughout the tropics in evergreen montane forests, and in the wet Andean grass and shrublands in South America. In Panamá, species diversity is strongly concentrated in the Cordillera Talamanca in the western portion of the country (especially Prov. Chiriquí).

Phlegmariurus chiricanus and P. lancifolius appear to be endemic to Panamá; the former species has been reported from Volcán Turrialba in Costa Rica ( Rojas 2005) but we believe these plants to be P. talamancanus . ­­­ Phlegmariurus chamaeleon , P. foliaceus , P. hoffmannii , P. mesoamericanus , P. talamancanus , and P. tubulosus are all restricted to mountainous areas of Costa Rica and Panamá.

The genus Phlegmariurus until fairly recently was generally included in the genus Huperzia . However, Phlegmariurus is distinct from Huperzia with regard to spore type and the absence of gemmae. The species of Huperzia are entirely terrestrial whereas the majority of Phlegmariurus species are primarily epiphytic, the terrestrial species being derived from epiphytic species ( Testo et al., 2018b). No intergeneric hybrids are known ( Øllgaard 2012 b, Øllgaard & Windisch 2019).