What You Should Know
Hygrophorus agathosmus is a species of fungus in the family Hygrophoraceae. The fruit bodies are characterized by a light grayish cap that measures up to 8 cm (3.1 in) in diameter, waxy gills, a dry stem, and the distinct odor of bitter almonds. An edible but bland-tasting mushroom, extracts of the fruit bodies have been shown in laboratory tests to have antimicrobial activity against various bacteria that are pathogenic to humans.
Fairly common in the PNW, northern California, and the Rocky Mountains. It is less common elsewhere in North America and also occurs in Europe and Asia.
Other names: Almond-Scented Waxcap, Gray Almond Waxy-Cap, Almond Woodwax.
Hygrophorus agathosmus Mushroom Identification
Mycorrhizal with conifers; growing scattered or gregariously; late summer and fall, or overwinter in warmer climates; widely distributed in North America.
2-4.5 cm; convex when young, becoming broadly convex or nearly flat; sticky when fresh, but often drying out quickly; bald; brownish gray to gray.
Broadly attached to the stem or beginning to run down it; nearly distant; white; short-gills frequent.
4-8 cm long; 0.5-1.5 cm thick; more or less equal, or tapering to base; white to whitish throughout development; bald or finely silky.
White; unchanging when sliced.
Odor and Taste
Odor fragrant and sharp, reminiscent of almonds--or occasionally lacking; taste not distinctive.
Spores 7-10 x 4-5 µ; smooth; ellipsoid; smooth; hyaline in KOH; inamyloid. Hymenial cystidia absent. Basidia 4-sterigmate; 45-60 µ long. Lamellar trama divergent. Pileipellis an ixocutis.
Hygrophorus agathosmus Look-Alikes
A small species was reported from Idaho under conifers. It also has a viscid, grey cap, but the gills are strong, not subdecurrent.
Is a large, robust species, the cap up to 12 cm broad, with an ochre-tinged, brownish cap.
Has a brown to tawny-brown, often wavy-margined cap and occurs under spruce (Picea spp).
Resembles H. agathosmus and has a similar almond odor. However, the fruit bodies of H. pustulatus are smaller, and it produces larger spores (11–14 µm long).
Grows under conifers or oak, have a sticky stem and less pronounced almond odor.
Also similar in appearance, but it lacks a distinctive odor and has smaller spores than H. agathamosus.
Hygrophorus agathosmus Taxonomy and Etymology
The species was originally named Agaricus agathosmus by Swedish mycologist Elias Fries in 1815; he later moved it into the genus Hygrophorus in 1838. In the interim, English naturalist Miles Joseph Berkeley named the species Agaricus cerasinus in 1836, although he too would later transfer the species to Hygrophorus in 1860.
In 1948, Richard Dennis examined the type material, and concluded that the two names referred to the same species. Additional historical synonyms include Limacium pustulatum var. agathosmum (Kummer, 1871), and Limacium agathosmum (Wünsch, 1877).
In their 1963 monograph of the Hygrophorus of North America, American mycologists Lexemuel Ray Hesler and Alexander H. Smith classified H. agathosmus in the subsection Camarophylli, a grouping of related species characterized by a dry stem, and the absence of a gelatinous outer veil.
The specific epithet agathosmus is derived from the Greek word agathos meaning “good”, and osme meaning “scent”.
Photo 1 - Author: Ryane Snow (snowman) (Creative Commons Attribution-Share Alike 3.0 Unported)
Photo 2 - Author: Ryane Snow (snowman) (Creative Commons Attribution-Share Alike 3.0 Unported)
Photo 3 - Author: Jerzy Opioła (Creative Commons Attribution-Share Alike 3.0 Unported)
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