Dictyonema hirsutum Moncada & Lücking
Mycobank MB 517762
Thallus terricolous or between bryophytes, foliose, composed of semicircular to flabellate lobes 0.5–1 cm diam. wide and 200–300 mm thick, with thickened, involute margins; upper surface densely hirstute and covered with obliquely oriented, white trichomes 0.3–0.5 mm long and 20–30 µm thick at the base, composed of densely packed parallel hyphae; zone close to the lobe margin usually glabrous and olive-green, surface otherwise white; lower surface ecorticate, finely felty-byssoid, mottled pale brownish to bluish grey. Thallus in section with upper corticiform layer composed of loosely packed, intricate, 3–4 µm thick, colourless hyphae, irregular photobiont layer with groups of cyanobacterial cells wrapped in a dense, partially paraplectenchymatous, hyphal sheath, and thin medulla of loosely woven hyphae also forming the lower thallus surface; clamps not observed. Photobiont a chroococcoid morph of Rhizonema (Lücking et al., 2009), cells in groups of 4–8, groups 20–40 mm diam., individual cells ovoid-ellipsoid, 10–13 x 6–10 mm, olive green. Basidiocarps on lower side, forming pieces of flat crust, each 1–3 mm in diam.; hymenophore attached by basal layer to lower side of thallus lobes, beige; margin slightly involute when dry, pale beige to white. Basal layer byssoid, composed of loosely woven, 4–5 mm thick hyphae, 200–300 mm high, colourless; subhymenial layer composed of densely woven, short-celled hyphae, 50–90 mm high, colourless; hymenium composed of densely arranged, palisade-like, 30–40 x 4–5 mm, slightly clavate basidioles, colourless, non-amyloid. Basidiospores not observed.
The foliose forms of the genus Dictyonema are the most commonly collected basidiolichens; they usually grow at higher altitudes on soil or between bryophytes but also occur as epiphytes on trees (Chaves et al., 2004). A recent phylogenetic study suggested that the single foliose species distinguished by Parmasto (1978 D. glabratum (Spreng.) D. Hawksw., actually comprises several different species that are distinct morphologically and genetically (Chaves et al., 2004; Lawrey et al., 2009). Dictyonema hirstutum differs from D. glabratum s.str. in the dense layer of trichomes produced on the upper surface, together with the overall smaller lobes. Cora pavonia f. villosa Tomas., might represent the same taxon, but that epithet has not been used at the species level. Because of its small thalli and its growth over soil and between bryophytes, D. hirsutum is easily overlooked between vegetation but very conspicuous up close for its peculiar morphology.
The epithet refers to the conspicuously hirsute upper surface of the thallus lobes.
The new species is known from the paramo region near Bogotá at over 3000 m altitude.
Type:—COLOMBIA: Cundinamarca: Municipio de Choachí, Vereda el Verjón, Reserva Natural Matarredonda, vía Laguna El Verjón; 3220m; paramo vegetation; Aug 2008, Lücking s.n. (holotype UDBC; isotype F).
Additional specimens examined (paratypes):—None.
Sicut Dictyonema glabratum sed thallo hirsuto differt.