TYPE. UNITED STATES. NORTH CAROLINA, New Hanover County, Wrightsville [Beach], in sandy woods, 19.IX.1928, A.W. Evans 219 (US, holotype).
Description. Lichenized fungus.
Thallus dimorphic to fruticose. Primary thallus squamulose, disappearing; squamules ~1 x 0.5 mm, margins entire or sparingly lobed with rounded apices. Podetia yellow-green, highly branched, thin, 50 mm long by 0.5-0.6 mm diam., forming prostrate colonies of crowded podetia; branching dichotomous or polychotomous; axils perforated or closed; cups lacking. Podetial surface corticate, smooth to areolate. Photobiont trebouxioid alga. Ascomata biatorine apothecia, brown to black, 0.2-0.4 mm diam., occurring singly or in clusters on podetial branch tips. Pycnidia blackish, 0.18-0.3 x 0.12 mm, on branch tips; pycnidial jelly hyaline; conidia curved, 4-6 x 0.5 μm.
Chemistry. KC+ yellow, PD+ pale yellow; usnic, squamatic and baeomycesic acids.
Substrate and Habitat. On sandy soil in open sand habitats of white sand scrub and pine woodlands.
Distribution. Coastal southeastern North America; in North Carolina in the Coastal Plain ecoregion.
Notes.Cladonia subsetacea is under assessment for IUCN Fungal Red-listing due to its specialized habitat, restricted range and decreasing population trends (http://iucn.ekoo.se/iucn/species_view/365721/, accessed 3 Oct 2022).
Ahti, T. (1973) Taxonomic notes on some species of Cladonia, subsect. Unciales. Annales Botanici Fennici10(3): 163-184.
Evans, A.W. (1947) A study of certain North American Cladoniae. The Bryologist50: 14-51 (original description).