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Lactarius porninsis

[ Basidiomycota > Russulales > Russulaceae > Lactarius . . . ]

by Michael Kuo

Lactarius porninsis is an Alpine and Carpathian species strictly associated with European larch. In some ways it is a bit unremarkable; it is yet another medium-sized, orange milky cap, and it lacks most of the distinguishing features found in similar species (no pot-holes on the stem, no dramatic green staining, no excruciatingly acrid taste, no colored latex). But it is associated with one of the world's more beautiful trees and finding it in the fall means you are surrounded by the gorgeous yellow and dull orange hues of the larches as their needles begin to fall, contrasting with the deep greens of the non-deciduous spruces—all set against the snow-topped mountains.


Ecology: Mycorrhizal with European larch; growing alone, scattered, or gregariously; summer and fall; found throughout the range of the host tree (the Alps and the Carpathians) and, reportedly, where European larch is planted as an ornamental or has been introduced. The illustrated and described collection is from northwest Italy, about 50 miles (as the crow flies) from the type locality near Chamonix, France.

Cap: 4–8 cm; convex at first, becoming more or less flat, or shallowly depressed; sticky; bald; finely rugged; bright orange, becoming duller with age; not zoned, or zoned faintly toward the margin; the margin not lined.

Gills: Broadly attached to the stem or beginning to run down it; close; short-gills frequent; pale orange.

Stem: 2–4 cm long; 1–1.5 cm thick; slightly tapered to the base; without potholes; bald; pale orange; basal mycelium white.

Flesh: Whitish to pale orange; unchanging when sliced.

Milk: White; scant; unchanging when exposed to air.

Odor and Taste: Not distinctive.

Spore Print: Undocumented by me; reported as "cream" by Heilmann-Clausen et al. (2000) and illustrated as pale orange by Kränzlin (2005).

Microscopic Features: Spores 8–11 x 7–8 µm; ellipsoid; ornamented with amyloid warts and ridges extending up to about 0.5 µm high; connectors fairly frequent, forming wide-meshed, partially reticulate patterns. Macrocystidia narrowly fusiform; to about 50 x 7.5 µm. Lactifers very abundant in hymenial trama. Pileipellis an ixocutis; elements 2.5–5 µm wide.

REFERENCES: Rolland, 1889. (Saccardo, 1891; Heilmann-Clausen et al., 2000; Kränzlin, 2005; Verbeken & Vesterholt, 2008.) Herb. Kuo 10141413.

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Lactarius porninsis

Lactarius porninsis

Lactarius porninsis
Spores (fine focus rolled to show ornamentation height)

Lactarius porninsis
European larch mixed with spruce in fall

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Kuo, M. (2016, January). Lactarius porninsis. Retrieved from the MushroomExpert.Com Web site: