Volvariella surrecta
Description
Volvariella surrecta is an inedible mushroom in the family Pluteaceae. It has white or grayish silky-hairy caps up to 8 cm (3.1 in) in diameter, and white gills that turn pink in maturity. The stipe, also white, is up to 9 cm (3.5 in) long, and has a sack-like volva at its base.
Grows as a parasite on the fruit bodies of other gilled mushrooms, usually Clitocybe nebularis. Although rare, the species is widely distributed, having been reported from Asia, North America, Northern Africa, Europe, and New Zealand.
Common names: Piggyback Rosegill.
Mushroom Identification
Cap
Initially ovoid (egg-shaped. Later they become bell-shaped or convex before flattening; reaching diameters of 2.5–8 cm (1.0–3.1 in). The cap sometimes has a shallow umbo, although the presence of this character is not consistent. The cap surface is dry and covered with long, silky hairs; the color is white to light gray, with a yellowish or brownish center.
Gills
The gills are free from attachment to the stipe and are packed close together. They are initially white, later becoming pink. There are many lamellulae (short gills that do not extend fully from cap margin to the stipe) interspersed between the gills.
Stipe
The stipe is 4–9 cm (1.6–3.5 in) long by 4–12 mm (0.16–0.47 in) thick, and roughly equal in width throughout the length or somewhat thicker at the base. Its color is white to light gray, and the stipe surface is appressed-fibrillose, with a pruinose coating near the apex. The white volva measures 1.3–2.5 cm (0.5–1.0 in) high and 0.6–1.3 cm (0.2–0.5 in) broad, and has a lobed margin.
Spores
Egg-shaped to oval, measuring 5.4–7.6 by 3.4–4.9 μm. The basidia (spore-bearing cells) are club-shaped, four-spored, and measure 20–31 by 5–10 μm. The pleurocystidia (cystidia on the gill face) are fusoid-ventricose (distinctly enlarged in the middle and tapered toward both ends), sometimes with an elongated neck. The cheilocystidia (cystidia on the gill edge) are also fusoid-ventricose with a neck that is sometimes short and bulbous; they measure 25–50 by 6–20 μm. The hyphae do not have clamp connections.
Spore Print
Brownish-pink.
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Similar Species
Because of its occurrence on the fruit bodies of other agarics, V. surrecta is unlikely to be confused with other mushrooms. Other parasitic mushrooms include Asterophora species, but these have thick gills compared to the thin gills of V. surrecta. Collybia species, including C. cookei, C. cirrhata and C. tuberosa are saprobic, and grow on the blackened, decayed remains of other agarics. Their fruit bodies are much smaller than V. surrecta, with cap diameters up to 2 cm (0.8 in). Although some other Volvariella species have an appearance similar to V. surrecta, they grow in grass or leaf litter.
History
When English botanist John Leonard Knapp (1767 - 1845) described this remarkable mushroom in his 1829 Journal of a Naturalist, he referred to it as Agaricus surrectus and stated that it grew from the back of another mushroom which he called Agaricus casaeus - almost certainly the Clouded Funnel Clitocybe nebularis.
In 1949 German-born American mycologist Rolf Singer redescribed this mushroom, transferring it to the genus Volvariella so that its scientific name became Volvariella surrecta.
Synonyms of Volvariella surrecta (Knapp) Singer include Agaricus surrectus Knapp, Agaricus loveianus Berk., Volvaria loveiana (Berk.) Gillet, and Volvaria surrecta (Knapp) Ramsb.
Volvariella, the genus name, is a reference to the volva formed around the stem base by the remnants of the membranous universal veil which covers embryonic fruit bodies.
The specific epithet surrecta comes from the Latin surrectus meaning arisen.
Photo sources:
Photo 1 - Author: bjoerns (CC BY-SA 4.0)
Photo 2 - Author: Garrett Taylor (CC BY-SA 4.0)
Photo 3 - Author: Garrett Taylor (CC BY-SA 4.0)
