''Russula claroflava'', commonly known as the yellow swamp russula or yellow swamp brittlegill, is a

basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basi ...

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is t ...

of the genus '' Russula''. It is found in wet places under

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 ...

and

aspen Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the ''Populus'' genus. Species These species are called aspens: *'' Populus adenopoda'' – Chinese aspen (China ...

woodlands across Europe and North America. It has a yellow cap, white gills and stipe and bruises grey. It is mild-tasting and regarded as good to eat.

Taxonomy

It was described in 1888 by

William Bywater Grove William Bywater Grove (24 October 1848 – 6 January 1938), was an English biologist, in particular a botanist and microbiologist. He is remembered in particular as a mycologist. He died in 1938 on the sixth of January when he was 89.New York Bota ...

, based on a specimen from Sutton Park in the English Midlands. Its

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

is derived from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''clarus'' 'bright' or 'clear', and ''flava'' 'light yellow'.

Description

This medium-sized member of the genus '' Russula'' has a cap that is an egg-yolk yellow. Measuring 4–10 cm (1.5 4 in) in diameter, it is slightly sticky when moist, and leaves and other debris often stick to it. There is usually a slight depression in the centre of mature specimens, with the margin becoming furrowed. The cap is half peeling. The high

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

is white, fairly firm, straight and 1–2 cm thick. Its gills are pale ochre, and are adnexed to almost free. All parts turn dark grey on aging or bruising. The smell is fruity and the spore print is pale ochre, and the oval warty spores average 9.5 x 8

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

. The edible but acrid ''

Russula ochroleuca ''Russula ochroleuca'' is a member of the genus '' Russula''. A group that have become known as brittlegills. It has been commonly known as the common yellow russula for some years, and latterly the ochre brittlegill. It is widespread, and comm ...

'' resembles this species, but has a duller yellow cap.

Distribution and habitat

''Russula claroflava'' appears in summer and autumn, usually with birch ('' Betula''), or aspen (''

Populus ''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood. The we ...

''), on heaths and moors, preferring damp places near ponds or lakes, often occurring in sphagnum. It is occasionally found in drier places. It occurs in Britain, across northern Europe, and throughout North America.

Edibility

This mushroom is

edible An edible item is any item that is safe for humans to eat. "Edible" is differentiated from "eatable" because it does not indicate how an item tastes, only whether it is fit to be eaten. Nonpoisonous items found in nature – such as some mushroo ...

and good, with a mild taste, both in Europe and North America.

References

Cited literature