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Russula fragiloides Murrill
Lloydia 8 (4): 265. 1945.

Original diagnosis

Pileo convexo-plano, 2.5–3 cm. lato, viscido, glabro, rubro, piperato; lamellis adnatis, confertis, angustatis, albis; sporis ellipsoideis, echinulatis, albis, 7–8×5–6µ; stipite albo, glabro, 3.5×0.5–0.7 cm.

Pileus convex to plane, scattered, 2.5–3 cm. broad; surface viscid when wet, smooth, glabrous, ruber, margin entire, even to slightly striate; context very thin, white, unchanging, odorless, very acrid at once; lamellae adnate, few inserted, narrow, crowded, entire, white, pallid on drying; spores broadly ellipsoid, white, distinctly short-echinulate, about 7–8×5–6 µ; sterile cells abundant, fusiform, abruptly apiculate, about 60×10µ, confined to the edges of the lamellae; stipe increasing below, smooth, white, glabrous, about 3.5×0.5–0.7 cm.

Type collected by W. A. Murrill in leaf mold in laurel-oak woods at Gainesville, Fla., Apr. 13, 1944 (F 18001). Closely resembling R. fragiliformis Burl. but with smaller, more elongate spores. Bresadola describes the spores of that species (R. fragilis Pers.) as globose or subglobose, 8–10×7–9µ. I am aware that the form of my specific name is old-fashioned but I use it intentionally to suggest the close relationship.


Holotypus: 18001 (F)
North America: United States: Florida: Gainesville
In leaf mold in laurel-oak woods

Published type studies: Hesler (1960).




SEM photos