Russula aurea
Description
Russula aurea (syn. Russula aurata) is an uncommon species of mushroom found in deciduous woodland under broad-leaf trees in summer and early autumn. Unlike many red-capped members of the genus, it is edible and mild-tasting. Good specimens are rare because slugs just love them.
Common names: Gilded Brittlegill, Gylden Skørhat (Danish), Russule Dorée (French), Gold-Täubling (German), Aranyos Galambgomba (Hungarian), Gullkremle (Norwegian).
Mushroom Identification
Cap
5-10 cm, from convex to flattened, depressed when ripe, fleshy; the cuticle is detachable by about half of the radius, smooth, opaque with dry weather, shiny and almost limy when the same is humid; the color is red-orange, yellow-orange, red-brown with yellow spots, or even completely yellow, at times the disc is darker, almost brown; the margin is smooth, thin, just striated when completely ripe.
Hymenium
Adnate gills, thick, frail, with lamellulas, furcations especially close to the stipe, the color is whitish or cream with lemon-yellow thread; spores white in mass.
Stipe
4-8 × 1,5-3 cm, cylindrical, enlarged or flared at the attachment to the cap, attenuated towards the base, full then crumbly, wrinkled or even smooth in some specimens, white with yellow-lemon hues.
Flesh
Initially firm then flabbier when ripe, frail, white, odorless, mild taste.
Habitat
Grows under broad-leaved trees (Quercus, Fagus and Castanea), as well as under conifers (Abies and Picea), in humid zones, from early summer to autumn, isolated or gregarious. It is present in most of Europe, and also in North America and Asia.
Chemical Reactions
Ferrous sulphate: on the flesh, it reacts slowly to the weak yellow-orange; Tincture of guaiac: on the flesh gives a rapid and intense reaction; Phenol: on the flesh gives a brown-chocolate-reddish reaction.
Microscopy
Rounded spores, crested or almost reticulated, little amyloid, 8-10 × 6-8 µm. Clavate basidia, tetrasporic, without clamp connections, 40-52 × 13,5-16 µm. Fusiform cystidia, with pointed or rounded apex, 65-76 × 11-13 µm. Pileipellis formed by hairs without dermatocystidia and crusted primordial hyphae.
Similar Species
Russula paludosa is a red species that sometimes has an orange tinge to its cap, but the stem remains white or pale pink rather than turning golden yellow.
History
English botanist William Withering (1741 - 1799) described this mushroom in 1801 and named it Agaricus auratus.
The Gilded Brittlegill was transferred to the Russula genus in 1838 by the great Swedish mycologist Elias Magnus Fries and it took on the name Russula aurata (With.) Fr.; however, the name Russula aurea already existed, having been established in 1796 by Christian Hendrik Persoon, and under the ICBN rules this name must take precedence.
Synonyms of Russula aurea include Agaricus auratus With., and Russula aurata (With.) Fr.
Russula, the generic name, means red or reddish, and indeed many of the brittlegills have red caps (but many more are not, and some of those that are usually red can also occur in other colors!). The specific epithet aurea means golden.
Medicinal Properties
Antitumor effects. Polysaccharides extracted from the mycelial culture of R. aurea and administered intraperitoneally into white mice at a dosage of 300 mg/kg inhibited the growth of Sarcoma 180 and Ehrlich solid cancers by 70% and 60%, respectively (Ohtsuka et al., 1973).
Photo sources:
Photo 1 - Author: Adrien BENOIT à la GUILLAUME (CC BY-SA 4.0)
Photo 2 - Author: archenzo (CC BY-SA 3.0)
Photo 3 - Author: Russula_Aurea.JPG: archenzoderivative work: Ak ccm (talk) (CC BY-SA 3.0)
Photo 4 - Author: Holger Krisp (CC BY-SA 4.0)