Lactifluus piperatus

Did You Know?

• Lactifluus piperatus is a common food source for red squirrels.
• The pleasing fungus beetle Tritoma angulata uses L. piperatus as its most important adult and larval food source.
• In the 19th century, it was used as a folk cure for tuberculosis, though it had no effect.

Taxonomy

Carl Linnaeus officially described the species as Agaricus piperatus in Volume Two of his Species Plantarum (1753), the specific epithet piperatus meaning 'peppery'. For many years, Tyrolian naturalist Giovanni Antonio Scopoli was credited with the first description until a 1987 revision of the International Code of Botanical Nomenclature began considering works from 1753 instead of only 1821. Lactifluus piperatus was the original type species of Lactarius, but after the genus was found to represent more than one lineage, Lactarius torminosus was conserved as the type for Lactarius, making L. piperatus the type species of Lactifluus.

Description

The cap measures 6-16 cm across, is convex with a depressed center, creamy-white staining tannish with age, and glabrous but not glossy, sometimes cracking in dry areas. The stipe is white, smooth, 2-8 cm long and 1-3 cm thick, cylindrical and sometimes tapering toward the base. The flesh is firm and white, and the decurrent gills are exceptionally crowded and narrow, white becoming creamy with age. The abundant white latex dries olive-green. The spore print is white, with elongate, elliptic or amyloid spores ornamented with tiny warts, measuring 4.5–9.5 by 5–8 μm. Similar species include L. vellereus, Russula delica, L. deceptivus, and L. glaucescens.

Distribution and habitat

In the wide sense, Lactifluus piperatus is found in Europe, the Black Sea region in northeastern Turkey, and eastern and central North America east of Minnesota, and has been accidentally introduced into Australasia. It grows on the forest floor in deciduous woodland, particularly under beech, fruiting throughout summer and autumn into early winter. It is relatively common, found solitarily or in scattered groups, and sometimes grows together with Russula cyanoxantha.

Edibility

The species contains toxins, and while some authors describe it as inedible or poisonous, it is often considered edible. It is difficult to digest raw and has an unpleasant taste, but can be used as a seasoning when dried, or eaten fresh after parboiling, though the taste remains unappetising. The hot, acrid milk is removed by boiling. In Russia it was highly regarded and picked in dry seasons when other edibles were scarce; in Finland it is boiled repeatedly, stored in salt water, then pickled or served in salads. Raw, it can cause an irritant reaction on the lips and tongue that subsides after an hour. When parasitized by Hypomyces lactifluorum (the lobster mushroom), an orange-red crust forms and the taste becomes delicious, as the parasite stops production of compounds toxic to humans.