Volvopluteus gloiocephalus
Description
Volvopluteus gloiocephalus is a species of mushroom in the family Pluteaceae. For most of the 20th century it has been known under the names Volvariella gloiocephala or Volvariella speciosa, but recent molecular studies have placed it as the type species of the genus Volvopluteus, newly created in 2011.
This mushroom is most often seen in fields that have been harvested of a grain crop (or occasionally some other food crop such as cabbages). It is even more widespread and abundant in southern mainland Europe, often recurring in the same grassy areas for many years.
The cap is white to grey, with a central umbo; its margin is striate. The cap surface is smooth, viscid or sticky. The stem is slender, bulbous, with a white sheathing volva, without ring. The flesh is unchanging; its taste is mild, radish-like; the odor is faint, unpleasant of radish or raw potato; its texture is fibrous. The gills are white, then pink brownish, free, crowded. The fruiting period takes place from April to November.
Volvopluteus gloiocephalus is sometimes mistaken for an Amanita because of its stature, free gills and volva. However, at maturity its salmon-colored gills and spores easily distinguish it from Amanita species.
Common names: Stubble Rosegill, Pink-spored Grisette, Green-capped Grisette, Big Sheath Mushroom, Rose-Gilled Grisette.
Mushroom Identification
Ecology
Saprobic; growing terrestrially, alone or gregariously in urban settings and disturbed ground (landscaping, ditches, beaches, lawns, gardens, and so on)—and, east of the Rocky Mountains, sometimes in forests; found year-round, depending on the climate; widely distributed in North America, though some records of it from east of the Rocky Mountains may represent other similar species, including the smaller-spored Volvopluteus michiganensis.
Cap
5–10 cm across; convex becoming broadly convex, broadly bell-shaped, or nearly flat; sticky when fresh and young but often soon dry; bald; color variable, white to grayish or gray, discoloring brownish to yellowish with age; when gray, with a radially streaked, appressed-fibrillose appearance; the margin sometimes finely lined.
Gills
Free from the stem; close or nearly crowded; short-gills frequent; white at first, becoming brownish pink with maturity.
Stem
6–13 cm long; 1–2 cm thick; tapered to apex; base slightly swollen; dry; bald or finely silky; white, discoloring brownish; without a ring; the base encased in a white, cup-like volva; basal mycelium white.
Flesh
White; not changing when sliced.
Odor and Taste
Not distinctive, or a little foul.
Chemical Reactions
KOH negative on cap surface.
Spore Print
Brownish pink.
Microscopic Features
Spores 13–19 x 7–10 µm; ellipsoid; thick-walled; smooth; hyaline to yellowish in KOH. Basidia 4-sterigmate. Cheilocystidia and pleurocystidia 50–80 x 20–40 µm; widely lageniform, widely cylindric with a rounded apex, subsaccate, or sphaeropedunculate; sometimes mucronate or rostrate; smooth; hyaline in KOH. Pileipellis a cutis of elements 5–12.5 µm wide, smooth, hyaline in KOH, under a very thin gelatinous matrix. Clamp connections not found.
Look-Alikes
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Has a very silky (almost hairy) cap and a volva; it grows on damaged hardwood trees and on their dead trunks and large branches.
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Has a stem ring and occurs in woodland habitats.
Medicinal Properties
Antitumor effects
Polysaccharides extracted from the mycelial culture of V. gloiocephala and administered intraperitoneally into white mice at a dosage of 300 mg/kg inhibited the growth of Sarcoma 180 and Ehrlich solid cancers by 90% and 80%, respectively (Ohtsuka et al., 1973).
History
When Swiss mycologist Augustin Pyramus de Candolle described this mushroom in 1815 he called it Agaricus gloiocephalus. Until recently its generally-accepted scientific name dated from 1986, when mycologists Teun Boekhout and Manfred Enderle gave it the name Volvariella gloiocephala. Then, in a 2011 publication by Italian mycologist Alfredo Vizzini and colleagues, the Stubble Rosegill acquired the new name Volvopluteus gloiocephalus.
Many older field guides use the name Volvaria speciosa when referring to this species, but now more authorities refer to it as Volvopluteus gloiocephalus (DC.) Vizzini, Contu & Justo (2011), with this being the type species of the newly created genus Volvopluteus.
Synonyms of Volvopluteus gloiocephalus include Agaricus gloiocephalus DC., Amanita speciosa Fr., Agaricus speciosus (Fr.) Fr., Volvaria speciosa (Fr.) P. Kumm., Volvaria gloiocephala (DC.) Gillet, Volvaria speciosa var. gloiocephala (DC.) R. Heim, Volvariella speciosa (Fr.) Singer, Volvariella speciosa var. gloiocephala (DC.) Singer, Volvariella speciosa f. gloiocephala (DC.) Courtec., and Volvariella gloiocephala (DC.) Boekhout & Enderle.
Volvopluteus, the genus name, is a reference to the volva formed around the stem base by the remnants of the membranous universal veil which covers emerging fruitbodies, and its relationship with another pink-spored genus the shield mushrooms, Pluteus species. The specific epithet gloiocephalus comes from the Greek words gloio, meaning glue or glutinous substance, and cephalus, meaning head. Hence gloiocephalus means with a sticky head - a reference to the viscid nature of the surface of caps of the Stubble Rosegill.
Photo sources:
Photo 1 - Author: Strobilomyces (CC BY-SA 3.0)
Photo 2 - Author: Alex (Public Domain)
Photo 3 - Author: davidwhyte (David Whyte) (CC BY-SA 4.0)
Photo 4 - Author: Jerzy Opioła (CC BY-SA 3.0)
