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"Lactarius deliciosus" [ Basidiomycetes > Russulales > Russulaceae > Lactarius . . . ] by Michael Kuo The mushroom we call "Lactarius deliciosus" in North America is fairly easily recognized. Its orange cap, gills, and stem discolor green when the mushroom is handled (and with age), distinguishing it from Lactarius thyinos, which does not bruise at all. It grows under conifers, and its milk is orange--in some versions staining the cut surfaces reddish or orange, and in other versions not staining. Lactarius experts have described several "varieties" of Lactarius deliciosus for North America, based on the precise color of the cap, the staining of the milk, and microscopic features (see the details below), but they all more or less share the features emphasized above. But our mushroom is apparently not the same as Lactarius deliciosus, which is a European species first described by Linnaeus in 1753. Researchers (Nuytinck and collaborators, 2006) have tested the DNA of European and North American versions of Lactarius deliciosus, and discovered that North American samples "form a separate clade and are not conspecific with L. deliciosus or with L. deterrimus occurring in Europe." Translation: ours are not the same. However, the precise identity (or identities) of our deliciosus-like mushrooms remains to be decided, and further research is required (probably coupled with extensive collecting and documentation; see this page if you or your mushroom club would like to help). "Lactarius deliciosus" is edible, though I do not recommend it; it has a rather grainy texture and sour taste. Some North American versions of the mushroom may be better than others--but none of them ranks very highly with most authors. Description: Ecology: Mycorrhizal with conifers, especially spruces; growing gregariously or scattered; summer and fall; widely distributed in northern and montane North America. Cap: 4-15 cm; at first convex with a central depression, becoming broadly vase-shaped; slimy to sticky when wet, but often dry; the margin sometimes inrolled when young; smooth or slightly rough; carrot orange or orange, with or without concentric zones of color; often discolored greenish at maturity. Gills: Running down the stem; close or crowded; orange or yellowish at first; usually bruising reddish, then greenish; frequently entirely greenish at maturity. Stem: 2-7 cm long; 1-2 cm thick; orange; more or less equal; smooth, with or without potholes; often becoming hollow; bruising and discoloring greenish. Flesh: Pale yellowish to orange, staining to reddish on exposure, then greenish. Milk: Orange to reddish orange; scanty in some varieties. Odor and Taste: Odor not distinctive or fruity; taste mild to slowly slightly acrid. Spore Print: Pale cream to buff. Microscopic Features: See the descriptions of varieties below. REFERENCES: (Linnaeus, 1753) S. F. Gray, 1821. (Fries, 1821; Saccardo, 1887; Coker, 1918; Kauffman, 1918; Smith, 1975; Hesler & Smith, 1979; Smith, Smith & Weber, 1979; Arora, 1986; States, 1990; Phillips, 1991/2005; Lincoff, 1992; Evenson, 1997; Methven, 1997; Heilmann-Clausen et al., 1998; Barron, 1999; Roody, 2003; Nuytinck & Verbeken, 2005; McNeil, 2006; Miller & Miller, 2006; Nuytinck et al., 2006; Kuo, 2007.) Herb. Kuo 09019401, 08080503. North American Varieties Hesler & Smith (1979) and Methven (1997) describe the following varieties of Lactarius deliciosus: Lactrius deliciosus var. areolatus grows under mixed conifers, and is western and montane. It is characterized by its very scant orange milk that stains the flesh reddish, and a cap surface that becomes noticeably roughened from dry conditions. It has spores 8.5-11 x 6-8.5 µ, ornamented with a broken reticulum with prominences .3-.5 µ high. It lacks prominent pleurocystidia. Lactrius deliciosus var. deterrimus, as described by Hesler & Smith (1979), grows in cold wet conifer forests and bogs, and is documented from Michigan; it may be eastern in distribution. It has bright orange milk that stains the flesh purplish red. Its more or less smooth cap sometimes has a sheen, and the milk is fairly copious under normal weather conditions. It has spores 7.5-9 x 6-7 µ, ornamented with a broken reticulum with prominences .5-.8 µ high. It lacks prominent pleurocystidia. The North American taxon is apparently not genetically identical to the European Lactarius deterrimus, however, and the taxon name "deterrimus" is thus not accurate. Lactrius deliciosus var. olivaceosordidus grows under Sitka spruce in the Pacific Northwest. It is an eager green-bruiser, and even young mushrooms are frequently discolored green. The flesh is yellowish when cut. The milk is scanty, and the staining/bruising reactions may be directly green, without reddish or orange stages. It has spores 8.5-10.5 x 6.5-8 µ, ornamented with a broken reticulum with prominences about .5 µ high. Prominent pleurocystidia are present. Lactrius deliciosus var. piceus grows under spruce on the West Coast. Its flesh stains slowly red when cut. It has spores 7.5-9 x 6-7.5 µ, usually ornamented with a broken reticulum with prominences .2-.4 µ high. Prominent pleurocystidia are present. According to Nuytinck and collaborators (2006), Lactarius deliciosus var. piceus is an invalid name (it is a taxonomic synonym for Lactarius deterrimus). Further Online Information: L. deliciosus var. deliciosus in Hesler & Smith (1979) |
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Cite this page as: Kuo, M. (2007, September). Lactarius deliciosus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/lactarius_deliciosus.html |