Thallus pendulous, 10-30 mm, base not darkened, branching in uneven dichotomies with some perpendicular side branches; primary branches uniformly slender, up to 0.4 mm diam., segmented with conspicuous, somewhat swollen, white annulations, round in cross section; secondary branches sparse. Vegetative diaspores absent. Surface smooth, greenish or yellow-green. Cortex thin (9-12%); medulla white, dense, almost powdery (16-21%); axis reddish to brown, rarely white (37-50%). Photobiont chlorococcoid alga. Ascomata not reported.
Chemistry. Three chemotypes are recognized by Lendemer & Noell (2018):
Substrate and Habitat. Corticolous on branches in relatively open sites
Distribution. Central to North America, Caribbean; in North Carolina found throughout.
Acharius, E. (1803) Methodus qua Omnes Detectos Lichenes Secundum Organa Carpomorpha ad Genera, Species et Varietates Redigere atque Observationibus Illustrare Tentavit Erik Acharius. 394 pp. (original description).
Brodo, I.M., S. Duran Sharnoff & S. Sharnoff. (2001) Lichens of North America. Yale University Press, New Haven & London. 795 pp.
Lendemer, J.C. & N. Noell. (2018) Delmarva Lichens: An illustrated manual. Memoirs of the Torrey Botanical Society28: 1-386.