Plants globose, at first submerged, becoming superficial and expanded when 3-6 cm. across. Exoperidium split to about the middle into 4-5 expanded rays; mycelial layer remaining as a hollow cup in the substratum, the inner fibrous and fleshy layers becoming strongly fornicate but remaining attached at the apices to the basal cup, rays firm, thick, brown; fleshy layer brown, partly flaking away from old specimens; base strongly convex. Endoperidium pedicellate, to 3 cm. diameter, depressed globose, urceolate, with a constricted ring-like apophysis above the pedicel, ferruginous, finely pubescent; stoma naked, conical or mammiform, tubular, apex fibrillose or lacerate. Gleba ferruginous, pseudo-columella long-elliptical. Spores globose, 4-5um diameter, epispore umber, 0.75um thick, moderately and finely verrucose. The species may be identified readily by the fornicate exoperidium, being liable to confusion in this particular only with occasional specimens of G.minus and the extra-territorial G.radicans. It is separated by the naked stoma. Occasional plants do not become fornicate, but remain in the expanded condition. In Europe the species has frequently been listed as Geaster fornicatus (Huds.) Fr. The name is untenable, however; for as Lloyd has frequently pointed out, Fries included under the name both G.fenestriatum and G.minus. Persoon, on the other hand, clearly recognized the differences between these two, and placed them under Geastrum quadrifidum var. fenestriatum and var. minus respectively. They are quite distinct, differing both in size and the structure of the stoma, that of the former being naked, the latter fibrillose. Exceptions occur, since in a collection of G.fene striatum sent from California by Miss E. Morse, a single plant with fibrillose stoma was present.

DISTRIBUTION : Britain; Europe; North America; West Indies; Africa; Australia. Victoria: Ninety Mile Beach; Unknown Locality (4). South Australia: Pearson Island, Great Australian Bight; Overland Corner; Kinchina (1). Western Australia: Bunbury (1).

TYPE LOCALITY: Europe.