Cladonia gracilis

Podetia 1–6 cm tall, slender, 0.5–1.5 mm diam., greenish grey or often olive to dark brown, often becoming dark brown-black towards the base, unbranched or sparingly branched, pointed at apices or usually some with a terminal, ± regular, shallow cups 1–2 mm in diam., not perforate, often with dentate margins, sometimes proliferating from the rim; surface smooth, corticate, usually conspicuously but finely areolate (×20 lens), attached squamules usually absent or scarce. Basal squamules to 2 mm, indented, mostly disappearing. Apothecia and pycnidia dark brown, at apices of podetia; apothecia rather rare; pycnidia frequent. Thallus C–, K–, KC–, Pd+ red, UV– (fumarprotocetraric acid).

Characterised by the slender habit and clustered, smooth, mostly unbranched, erect podetia, some of which are either pointed or terminate in small, non-perforate cups. Cladonia furcata lacks cups and has perforate branch axils; C. cornuta has a similar habit but podetia have a sorediate upper half and smooth, corticate lower part; C. crispata var. cetrariiformis has perforate cups, is more branched and is Pd–, UV+ white (squamatic acid). See also C. maxima and C. trassii.