Phlegmariurus tenuis (Willdenow) B. Øllgaard (2012b: 19)

Øllgaard, Benjamin & Testo, Weston, 2021, The Lycopodiaceae of Panamá, Phytotaxa 526 (1), pp. 1-66 : 42

2.­­­ Phlegmariurus tenuis (Willdenow) B. Øllgaard (2012b: 19) . Fig. 10A–B

Lycopodium tenue Willdenow (1810: 55) .— Huperzia tenuis (Willdenow) Trevisan (1874: 248) .— Urostachys tenuis (Willdenow) Nessel (1927: 401) . Type:— ECUADOR. Loja: Valley of Vinajacu, near Loja, Humboldt & Bonpland 3363 (B-Willdenow no. 19423 holotype; BM, LG, P00669229 isotypes).

Usually epiphytic, delicate to extremely delicate, flaccidly pendulous, at least to 75 cm long. Shoots gradually heterophyllous, 3–8 mm in diameter including the leaves in the basal divisions, tapering to 1–3 mm in diameter in the narrow terminal divisions. Stems excluding leaves 0.5–0.7 mm thick at the base, tapering to ca. 0.3 mm upward, pale greenish to stramineous, at least to 10 times dichotomous, usually discontinuously and unilaterally sporangiate from 10–30 cm above the base and upward. Leaves of basal divisions borne in irregular alternating whorls of 3–5, or spirally arranged, forming 6–10 indistinct longitudinal ranks, usually densely crowded, spreading to ascending, straight to somewhat curved, often secund, acicular, tapering from a subauriculate base, 3–5 (–7) × 0.3–0.5 mm, decurrent. Vegetative leaves and sporophylls of constricted terminal divisions almost conform, borne in alternating irregular whorls of 3, or irregularly alternate, patently diverging from the stem, with upward curved tips, widely ovate to subhastate, 1–3 × 0.5–1.4 mm wide at the base, clasping with the base, tapering to abruptly narrowed into a short to long acuminate apex, bluntly to sharply carinate, usually unilaterally, discontinuously, but often densely sporangiate. Sporangia 0.8–1.2 mm wide.

­­­ Distribution:— Costa Rica, Panamá, Andes from Venezuela to Bolivia.

Habitats:— Epiphytic in uppermost montane forests, elev. 2800–3500 m elev.

Notes:— Phlegmariurus tenuis exhibits the same type of size variation as mentioned for P. curvifolius . Some forms are almost as extremely fragile and slender but are easily distinguished by the spreading leaves in the terminal divisions. This species is also ecologically distinct, being restricted to the uppermost montane forests. The Central American plants are generally larger and more robust than the Andean ones.

­­­ Specimens­­­studied:—Chiriquí: Boquete, Volcán de Chiriquí, 3200 m, Davidson 1021 (GH, MO, US). Ridge above Alto Pineda, 2835 m, Hammel et al. 7101 (MO). Boquete, Volcán de Chiriquí, 3200 m, Terry 1021 (MO, NO, US)