Russula delica
Description
Russula delica is one of the largest mushrooms in the Russula genus. It emerges from the earth pushing up pine needles, turf or leaf litter; hence, the large off-white cap is usually badly marked and often damaged. It is mostly white, with ochraceous or brownish cap markings, and a short robust stem.
This mushroom is edible but poor, having an unpleasant taste, leading some to classify it as inedible. However, in Cyprus, as well as certain Greek islands such as Lesvos, huge numbers of Russula delica are collected and consumed every year. They are usually pickled and preserved in olive oil, vinegar or brine, after prolonged boiling.
It is quite easily recognized due to the rather big size, the spaced and broad gills, the shape of the rather irregular cap, the fruity smell, especially when young, becoming unpleasant in the adult individual, and the just peppery flavor.
Common names: Milk White Brittlegill, Milk White Russula; Colombina Bianca, Rossola Delicata, Durello, Peperone (Italy); Russule Faux-Lactaire, Russule Sans Lait, Prévat (France); Rúsula Blanca, Pebrás, Gibelzuri Orrizabal (Spain); Blaublättriger, Weisstäubling, Gewöhnlichez (Germany).
Mushroom Identification
Cap
5-15 cm, initially hemispheric, then convex, bun liken umbilicate, finally flattened, depressed up to crateriform or funnel-shaped; margin initially inrolled for a long time, then straight, thin, undulated, lobed, not grooved; dry surface, rugged, opaque, also little felted, initially white, then with ochre or brownish dots, almost completely covered by mold and leaves which it traps when it comes out from the soil in the growth.
Hymenium
Moderately spaced gills, adnate or just decurrent, wide, thick, rigid, and frail in the meantime, rather uneven, inconstantly forked, intercalated by variously long lamellulae; whitish, cream, rust-spotted, concolorous, entire, edge.
Stem
2,5-5 x 1,5-3,5 cm, cylindroid, short and stocky, expanded from bottom to top, compact, hard, full, then spongy; the surface is rather pruinose, rugged, white, then with brownish spots.
Flesh
Thick, compact, frail, from compact to spongy, and often wormy in the stem; white, tend to become brown when cut. The smell of fish, of salt or fruit, tending to have one prevailing on the other; mild taste on the flesh, somewhat spicy on the gills.
Habitat
It grows in small groups, from spring to late autumn, in latifolious woods as well as in the conifer ones, in calcareous and dry soils.
Edibility
Mediocre edible is not appreciated due to the poor supply of flavor. We feel obliged to express our personal opinion on the gastronomic value of this fungus, even if we know that it is much sought for and eaten in some zones; however, we realize that this belongs to a gastronomic and cultural tradition worthy of attention.
Chemical reactions
It gives a rapid reaction to the dark green, on the flesh, to the Guaiacum tincture; it gives a slow reaction to the pale pink, on the flesh, to the ferrous sulphate (FeSO4).
Microscopy
Ovoid, sub-globose spores, echinulate with obtuse prickles, often cristate-catenulate with some thin connexion, 8-11 x 7-9 µm, little amyloid supra-hyphal notch. Clavate basidia, tetrasporic, without joint buckles, 52-60 x 11-13 µm. Cylindroid cystidia, fusiform, with obtuse or appendiculate apex, 68-150 x 8- 12µm. Cuticle with cylndroid hairs, septate, with rounded apex; cylindroid dermatocystidia, with few septa, becoming grey in sulphovanilline (SV).
Russula delica Similar Species
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Is very similar and often confused with R. delica. It can be separated by the turquoise band at the apex (at the attachment of the gills with the cap) and by its unpleasant, peppery smell.
Russula pallidospora
Is another similar species, which has very tough flesh, more distant gills and an ochraceous spore deposit.
Russula flavispora
Is also similar but rare, and has dense gills and a deep ochraceous spore deposit.
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Similar whitish milk-cap species, such as Lactifluus piperatus all exude milk from the gills, and the cut flesh.
History
The currently-accepted scientific name of the Milk White Brittlegill was established in 1838, when Swedish mycologist Elias Magnus Fries described this species and gave it the binomial name Russula delica.
Synonyms of Russula delica include Lactarius piperatus ß exsuccus Pers., Lactarius exsuccus (Pers.) W.G. Sm., and Russula flavispora Romagn.
Russula, the generic name, means red or reddish, and indeed many of the brittlegills have red caps (but many more are not, and several of those that are usually red can also occur in a range of other colors!).
The specific epithet delica means 'without milk', which may seem a little odd given that this is a characteristic of all Russula species.
Photo sources:
Photo 1 - Author: Holger Krisp (CC BY 3.0)
Photo 2 - Author: gailhampshire from Cradley, Malvern, U.K (CC BY-SA 2.0)
Photo 3 - Author: gailhampshire from Cradley, Malvern, U.K (CC BY-SA 2.0)
Photo 4 - Author: Игорь Лебединский (CC BY 3.0)
