Ripartitella brasiliensis

[ Basidiomycetes > Agaricales > Tricholomataceae > Ripartitella . . . ]

by Michael Kuo

This fascinating mushroom is like a Gulf-Coast cross between Lepiota cristata and a wood-rotting species of Pholiota. It grows from dead wood--especially from oak logs--and is apparently limited to tropical and subtropical regions. In North America it is found along the Gulf Coast, but its range extends into the Caribbean and South America.

Identifying features for Ripartitella brasiliensis include its range and ecology; its white spore print; the Lepiota-like appearance; gills that are attached to the stem; and spiny, inamyloid spores.

Description:

Ecology: Saprobic on the dead wood of hardwoods, especially oaks; growing densely gregariously or in clusters; causing a white rot; summer, fall, and early winter; along the Gulf Coast.

Cap: 1-7 cm; convex, becoming broadly convex or nearly flat; dry; smooth and whitish underneath small, brown to reddish brown scales.

Gills: Attached to the stem; close; white.

Stem: 1-5 cm long; 2-6 mm thick; equal; dry; whitish underneath brown to reddish brown scales; with a clearly defined or vague ring zone; often with copious white basal mycelium.

Flesh: Whitish.

Odor & Taste: Not distinctive.

Chemical Reactions: KOH on cap surface negative. Ammonia pale grayish green on brown areas of cap surface.

Spore Print: White.

Microscopic Features: Spores 4.5-6 x 3.5-4.5 µ; elliptical; finely spiny; inamyloid. Pleurocystidia lageniform; to about 45 x 8 µ; apices encrusted with ornamentation that dissolves quickly in KOH mounts but remains visible in water or Melzer's mounts. Lamellar trama parallel. Pileipellis a cutis of elements 3.5-9 µ wide, with interspersed erect clusters of shorter, slightly inflated cells. Clamp connections present.

Synonyms include Lentodium floridanum, Marasmius squamosidiscus, Ripartitella squamosidisca, Pleurotus brasiliensis, Lepiota armillarioides, and Collybia pseudoboryana.

REFERENCES: (Spegazzini, 1889) Singer, 1951. (Saccardo, 1891; Murrill, 1940 [Marasmius squamosidiscus]; Ovrebo, 1988.)

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Cite this page as:

Kuo, M. (2008, January). Ripartitella brasiliensis. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/ripartitella_brasiliensis.html