Melanoleuca cognata
Description
Melanoleuca cognata is a medium or large mushroom, that is pale brown with an umbonate cap and white gills. It occurs often in the spring, when few other gilled mushrooms are fruiting, and grows solitary or scattered on soil and needle litter in coniferous woodlands; occasionally in litter-rich grassland, woodchip, or garden compost heaps. It is found in Europe and North America.
The main distinguishing features for M. cognata include its gills, which are initially white but soon turn yellowish-pinkish to pale tan - and its peculiar odor, somewhere between "sweet" and "mealy."
Melanoleuca cognata is edible, but is not highly regarded, is not common, and without a microscope can be hard to identify with certainty.
Common names: Spring Cavalier, Peach-gilled Melanoleuca.
Mushroom Identification
Ecology
Probably saprobic; found in woods (often under conifers) or grassy waste areas; spring, summer, and fall; widely distributed in North America.
Cap
5-13 cm across; broadly convex or flat, often with a very shallow central bump; smooth; greasy when fresh; brown when fresh, fading to tan; often with a slightly darker center.
Gills
Attached to the stem, usually with a "notch"; close or crowded; white at first, soon yellowish-pinkish to tan or pale brown.
Stem
6-12 cm long; up to 2 cm thick; equal; often somewhat twisted; dry; brownish or whitish; usually with tiny brown fibrils; basal mycelium white.
Flesh
Whitish.
Odor and Taste
Odor sweetly fragrant to mealy (often somewhere in between); odor of dried specimens pungent, like the odor of many mealy mushrooms when dried; taste not distinctive or sweetish-mealy.
Spore Print
White.
Microscopic Features
Spores 7-10 x 4.5-6.5 µ; more or less elliptical; ornamented with amyloid warts; apiculus inamyloid. Pleurocystidia and cheilocystidia are abundant; variously shaped but often fusoid-ventricose; often capped with apical incrustations; occasionally septate; up to 70 x 20 µ.
Similar Species
Melanoleuca melaleuca is macroscopically very similar, but it can be separated by microscopic examination of the spores, cystidia, etc.
History
In 1838 Swedish mycologist Elias Magnus Fries gave it the name Agaricus arcuatus var. cognatus. Its currently accepted scientific name Melanoleuca cognata dates from a 1926 publication by French mycologists Paul Konrad (1877 - 1948) and André Maublanc (1880 - 1958).
Synonyms of Melanoleuca cognata include Agaricus arcuatus var. cognatus Fr., Tricholoma cognatum (Fr.) Gillet, and Tricholoma arcuatum f. robusta J. E. Lange.
The genus name Melanoleuca comes from the Ancient Greek words melas meaning black, and leucos meaning white. No cavalier mushroom is truly black and white, but many have caps whose upper surfaces are various shades of brown, with whitish gills beneath.
The specific epithet cognata means 'born with', often interpreted as 'kindred' meaning closely related.
Photo sources:
Photo 1 - Author: Holger Krisp (CC BY 3.0)
Photo 2 - Author: Richard Daniel (RichardDaniel) (CC BY-SA 3.0)
Photo 3 - Author: Richard Daniel (RichardDaniel) (CC BY-SA 3.0)
Photo 4 - Author: Susanne Sourell (suse) (CC BY-SA 3.0)
