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Lactarius psammicola

[ Agaricomycetes > Russulales > Russulaceae > Lactarius . . . ]

by Michael Kuo

The mess surrounding the North American versions of the European species Lactarius zonarius gets my vote for All-Time Worst Lactarius Nightmare. We have, on our continent, a bunch of poorly understood and often poorly defined species, varieties, and forms that are similar to Lactarius zonarius. Among these, Lactarius psammicola is arguably the most clearly delineated and recognizable species. It is mycorrhizal with oaks in eastern North America and in Mexico, and can be distinguished by the following features:

  • A cap margin that is inrolled and hairy, at least when the mushroom is young.
  • A medium-sized to large cap that has concentric zones of orange shades and paler colors.
  • A stem with potholes.
  • Strongly acrid taste.

Lactarius psammicola is often one of the more conspicuous and prolific summer mushrooms in eastern North America's oak-hickory forests.

Description:

Ecology: Mycorrhizal with oaks and possibly other hardwoods; growing alone, scattered, or gregariously; summer and fall; widely distributed east of the Rocky Mountains.

Cap: 4-14 cm; at first with a deep central depression and an inrolled, hairy margin; later vase-shaped, with the margin typically remaining somewhat inrolled and softly leathery or finely hairy; slimy when fresh but soon dry; roughened; with buff and orange concentric zones of color.

Gills: Running down the stem; close; rarely forking near the stem; whitish or buff, becoming darker and dirty; sometimes bruising brownish to lilac brown.

Stem: 1-3 cm long; 1-2 cm thick; whitish, sometimes discoloring brownish where handled; tapering to base; with potholes.

Flesh: Thick; white; unchanging when sliced.

Milk: White; unchanging; not staining tissues, or staining them slowly brownish to lilac brownish; slowly staining white paper yellow.

Odor and Taste: Odor not distinctive; taste strongly acrid.

Chemical Reactions: KOH negative on cap surface.

Spore Print: Yellowish to yellow.

Microscopic Features: Spores: 7.5-9 x 6-7.5 µ; broadly ellipsoid; ornamentation about 0.5 µ high, as isolated, amyloid warts and short ridges that occasionally form partial reticula. Pleuromacrocystidia inconspicuous; to about 50 µ long; subfusiform to subcylindric. Cheilocystidia similar. Pileipellis a thick ixocutis.

REFERENCES: Smith, 1941. (Hesler & Smith, 1979; Phillips, 1991/2005; Horn, Kay & Abel, 1993; Roody, 2003; McNeil, 2006.) Herb. Kuo 07089501, 08300202, 08300213, 09010201, 07070710.

Further Online Information:

Lactarius psammicola in Hesler & Smith (1979)
Lactarius psammicola at Macrofungi of Costa Rica

 

Lactarius psammicola

Lactarius psammicola

Lactarius psammicola

Lactarius psammicola
Spores

Lactarius psammicola
Pleuromacrocystidia



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Cite this page as:

Kuo, M. (2011, March). Lactarius psammicola. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/lactarius_psammicola.html