Deceiving milkcap

Appearance

The cap is 7.5–25.5 cm in diameter, initially convex, but becomes funnel-shaped in age. The margin is rolled inwards and cottony when young, concealing the immature gills. The cap surface is dry, smooth and whitish when young, often with yellowish or brownish stains, but becomes coarsely scaly and darkens to dull brownish-ochre with age. The gills have an adnate to decurrent attachment to the stem, close to subdistant, white at first then cream to pale ochre. They are 5–65 mm long and 1–7 mm deep. The stem is 4–10 cm long, up to 3 cm thick, nearly equal in width throughout or tapered downward. It is dry, scurfy to nearly smooth and white, staining brown with age. It is initially stuffed, but later becomes hollow. The flesh is thick and white, and between 3 and 15 mm thick. The latex produced by the mushroom is white, and does not change color upon exposure to air, although it stains the mushroom flesh a yellowish-brown color.

The odor of the flesh and latex may range from indistinct to pungent or turnip-like in age; the taste is strongly acrid—so much that it may have an anesthetizing effect in the throat. In his original description of the species, Peck reported "An experiment of its edible qualities was made without any evil consequences." Thorough cooking removes the bitter taste, but the mushroom is not highly regarded as an edible, and as Hesler and Smith have noted "... but even with this compensating feature some of our acquaintances have found it rather undesirable." The mushroom is sold at traditional markets in Puebla, Mexico.The spore print, freshly made, is white to whitish; after drying out the spores in mass are pale yellowish. The spores are broadly ellipsoid, hyaline and measure 9–13 by 7–9 µm. An apiculus is prominent. The spores are ornamented with warts and spines that do not form a reticulum on the surface. The prominences are up to 1.5 µm high, and amyloid, meaning they absorb iodine when stained with Melzer's reagent. The basidia are four-spored, and measure 46–58 by 7–9 µm. The pleurocystidia are very abundant, roughly club-shaped to ventricose, with apices often tapering; their dimensions are 48–96 x 6–10 µm. The cheilocystidia are 40–58 x 5–7 µm, and more or less similar in appearance to the pleurocystidia. The cap cuticle is made of a layer of somewhat uplifted hyphae. The stem cuticle is a layer of bent-over hyphae bearing thick-walled, filamentous caulocystidia, and it lacks a gelatinous layer.

Naming

The fungus "Lactifluus pseudodeceptivus" is very similar to "L. deceptivus" in its external appearance, but it has spore ornamentation that forms a reticulum, and its stem is an ixocutis. "L. caeruleitinctus" is also similar in appearance, but it has a milky-white stem with blue tints that develops more intense blue coloration after handling, and it lacks a cottony, inrolled margin. Other lookalike species include "Lactarius arcuatus", which has a much smaller cap and smaller spores, and "Lactarius parvulus", which has a small, zonate cap. "Russula brevipes" and "R. angustispora" are also somewhat similar in appearance, but they do not produce latex when cut or injured. "Lactifluus subvellereus" var. "subdistans" has more widely spaced gills, and an even cap margin. "Lactifluus piperatus" has densely crowded gills, a firm rather than soft and cottony cap margin, and exceedingly acrid latex.

Distribution

Like all milk-caps, "L. deceptivus" is mycorrhizal, meaning the fungus forms a mutualistic association with certain trees and shrubs. The subterranean mycelium of the fungus forms an intimate association with tree roots, enveloping them in a sheath of tissue that allows both organisms to exchange nutrients they would otherwise be unable to obtain. The fruit bodies of the fungus grow solitarily, scattered, or in groups on the ground in conifer or hardwood forests, often under oak or hemlock. Smith has noted a preference for bogs and the edges of woodland pools in hardwood forests, and in oak stands that have an understory of blueberry bushes. It is widely distributed in eastern North America, and has also been reported from southern and western Canada. It is a fairly common species, and fruits from June to October. The mushroom has also been reported from Mexico from oak and pine forests, at altitudes slightly over 2,000 meters, and from Costa Rica, where it is abundant in oak forests.

Habitat

Like all milk-caps, "L. deceptivus" is mycorrhizal, meaning the fungus forms a mutualistic association with certain trees and shrubs. The subterranean mycelium of the fungus forms an intimate association with tree roots, enveloping them in a sheath of tissue that allows both organisms to exchange nutrients they would otherwise be unable to obtain. The fruit bodies of the fungus grow solitarily, scattered, or in groups on the ground in conifer or hardwood forests, often under oak or hemlock. Smith has noted a preference for bogs and the edges of woodland pools in hardwood forests, and in oak stands that have an understory of blueberry bushes. It is widely distributed in eastern North America, and has also been reported from southern and western Canada. It is a fairly common species, and fruits from June to October. The mushroom has also been reported from Mexico from oak and pine forests, at altitudes slightly over 2,000 meters, and from Costa Rica, where it is abundant in oak forests.