Callistosporium purpureomarginatum

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by Michael Kuo

Callistosporium purpureomarginatum is a distinct little mushroom, found on the well-decayed wood of oaks. When fresh its cap is evenly purplish red, but it soon dries out in stages, creating a two-toned effect so that wishy-washy yellowish to purplish brown shades take over most of the cap, while a marginal zone darkens to purple. The gills, too, are distinctive, since they develop dark purple edges that contrast with the yellowish or purplish faces.

The range of Callistosporium purpureomarginatum has yet to be determined. It was initially described from New Jersey and North Carolina (Fatto & Bessette, 1996), but herbarium records at MycoPortal include collections from West Virginia and Tennessee. I have collected it in Illinois, and collections have been sent to me from Indiana, Maryland, Massachusetts, and Ohio. It is apparently an uncommonly found species; it was not described until 1996, it is only featured in a few field guides, and I have only seen it twice in 20 years of collecting.

Thanks to Lindsay Blevins, Nathaniel Cecil, Crystal Davidson, Django Grootmyers, Ron Kerner, and Jo and Bob Solem for collecting, documenting, and preserving Callistosporium purpureomarginatum for study; their collections are deposited in The Herbarium of Michael Kuo.

Description:

Ecology: Saprobic on the well-decayed wood of oaks; creating a brown, cubical rot; growing alone or gregariously; July through September; originally described from New Jersey and North Carolina; known distribution from Illinois to North Carolina and Massachusetts. The illustrated and described collections are from Illinois, Indiana, Maryland, Massachusetts, and Ohio.

Cap: 1–4 cm; convex, becoming planoconvex or flat; moist when fresh but soon dry; bald; purplish red to watery brownish purple with a pale whitish to olive bloom when fresh; changing color markedly as it dries out, creating a two-toned appearance with the marginal zone deep purple and the central area purplish to brownish or yellowish.

Gills: Broadly attached to the stem; close; short-gills frequent; deep brownish purple in buttons, but soon becoming dull yellow to olive purplish; edges becoming dark purple and contrasting with the faces.

Stem: 1.5–4 cm long; 2–5 mm thick; equal; fragile; hollowing; bald; yellow when young and fresh, but soon becoming brownish to grayish olive; basal mycelium whitish to yellowish.

Flesh: Thin; yellowish to brownish or purplish; unchanging when sliced.

Odor and Taste: Odor not distinctive; taste slightly bitter, or not distinctive.

Chemical Reactions: KOH on fresh cap surface quickly green, then black.

Spore Print: White.

Microscopic Features: Spores 4–7 x 2.5–4 µm; ellipsoid; smooth; inamyloid; hyaline and uniguttulate in KOH. Lamellar trama parallel. Basidia 4-spored. Pleurocystidia not found. Cheilocystidia 18–50 x 2–4 µm; cylindric with rounded or clavate apices; thin-walled; smooth; greenish or hyaline in KOH. Pileipellis a cutis of elements 2.5–7.5 µm wide; yellow-green in KOH. Clamp connections absent.

REFERENCES: Fatto & Bessette, 1996. (Bessette et al., 1997; Roody, 2003.) Herb. Kuo 07101602, 07281602, 08261602, 08271602, 09011602, 09031701, 08061803, 07202102.

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KOH

Spore print

Spores

Cheilocystidia

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Cite this page as:

Kuo, M. (2019, September). Callistosporium purpureomarginatum. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/callistosporium_purpureomarginatum.html