Russula fragrantissima & Russula laurocerasi

[ Basidiomycetes > Russulales > Russulaceae > Russula . . . ]

by Michael Kuo

These members of the Foetid Russulas Cluster are fairly easily separated from most of their close cousins. They are sturdier and more fragrant than Russula pectinatoides. They lack the orange colorations found in Russula subfoetens, and lack the granules found on the caps of Russula granulata and Russula pulverulenta. They are not brown and partial to conifers, like Russula cerolens and Russula amoenolens.

The process of elimination, then, eliminates all but Russula laurocerasi and Russula fragrantissima. Theoretically, Russula fragrantissima is larger and stockier, and more foul smelling, at least in age. Unfortunately, however, a microscope is probably required to be "certain" of identification. The spores of Russula laurocerasi are ornamented with very long spines and wide ridges, extending from 1 to 2.5 µ beyond the diameter of the spore; in Russula fragrantissima the ridges and spines rarely exceed 1 µ.

According to R. L. Shaffer's monograph of subsection Foetentinae (1972):

Compared with Russula fragrantissima, R. laurocerasi is a species having basidiocarps that retain a cleaner aspect as they mature and have yellower pilei, more slender stipes (in general, stipe three or more times longer than broad), a stronger, more fragrant odor, and larger spores with higher ornamentation. Intermediates between these species exist, however.

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The bit about "intermediates" is particularly frustrating. For example, I would have assigned the illustrated collection to Russula laurocerasi were it not for the spores, which do not exceed 10 µ, and do not demonstrate ornamentation extending beyond about 1 µ (in the illustration the fine focus has been set to depict the length of the spines, leaving the amyloid connecting lines mostly invisible; they formed partial reticula.) Let us hope that no one decides to do a thorough study of this species cluster and confuse things even more!

Neither Russula fragrantissima nor Russula laurocerasi is edible.

Description:

Ecology: Mycorrhizal with hardwoods or conifers; growing alone, scattered, or gregariously; summer and fall; east of the Great Plains (although Arora describes a similar species in California).

Cap: 7.5-20 cm for Russula fragrantissima, 3.5-13 cm for Russula laurocerasi; convex or cushion-shaped when young, becoming broadly convex to flat, with or without a shallow depression; slimy when wet and fresh; yellowish to brownish yellow; the margin lined at maturity; the skin peeling away easily at the margin, sometimes beyond halfway to the center.

Gills: Attached to the stem; close or nearly distant; sometimes forked near the stem; whitish to yellowish white or orangish; often discoloring yellowish brown to brownish, but not bruising.

Stem: 7-15 cm long and 1.5-6 cm thick for Russula fragrantissima; 2.5-11 cm long and 1-3 cm thick for Russula laurocerasi; white, discoloring brownish to yellowish or reddish near the base; dry; often becoming cavernous; more or less smooth.

Flesh: Whitish; unchanging.

Taste: Mild to moderately acrid for Russula fragrantissima; acrid for Russula laurocerasi; odor fragrant, reminiscent of maraschino cherries, almonds, or benzaldehyde, but in Russula fragrantissima with a foul component which begins to take over, especially in age.

Spore Print: Pale orange yellow.

Microscopic Features: Russula fragrantissima: Spores 6-9 x 6-8 µ; broadly elliptical or nearly round; with warts and ridges up to 1 µ high, sometimes with connecting lines that may form a partial or nearly complete reticulum. Russula laurocerasi: Spores 7.5-11 x 7.5-9 µ; broadly elliptical or nearly round; with warts and ridges from 1-2.5 µ high (characterized by one author as "wings"), sometimes with connecting lines that may form a partial or nearly complete reticulum.

REFERENCES: R. fragrantissima: Romagnesi, 1967. R. laurocerasi: Melzer, 1920. (Shaffer, 1972; Smith, Smith & Weber, 1979; Arora, 1986; Phillips, 1991/2005; Lincoff, 1992; Roody, 2003.) Herb. Kuo 08050403.

Further Online Information:

Russula fragrantissima at Roger's Mushrooms
Russula laurocerasi at Roger's Mushrooms
Russula laurocerasi at Fungi of Poland

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