Russulaceae

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Russulaceae
Russula emetica
Scientific classification
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Russulales
Family: Russulaceae
Lotsy
Type genus
Russula
Pers.
Genera

Boidinia
Cystangium
Lactarius
Multifurca
Pseudoxenasma
Russula
Zelleromyces

The Russulaceae are a family of fungi in the order Russulales. According to a 2008 estimate, the family contains 1243 species.[1] Its species typically have fruit bodies with friable, chalk-like stalks, that break with a distinct crack, somewhat like a carrot but with porous flesh (see below). Microscopically, the cells are not all long thin hyphae, which would provide strength and more fibrous appearance when broken. Instead, the flesh contains also many large spherical cells ("sphaerocysts"), which give rise to the macroscopic consistency.

Genera[edit]

The family is dominated by two well-known genera:

  • The genus Russula, sometimes known as brittlegills, comprises around 750 species, the majority of which are quite difficult to identify. They have splitting gills and do not exude a milky substance at cut surfaces, contrarily to the genus Lactarius. There are several edible species (Russula vesca, Russula virescens or Russula aurata).
  • The genus Lactarius, or milk-caps, characterised by caps and stalks that exude a milky substance ("latex") when pressed or cut and lactiferous, gloeoplerous hyphae, is a large genus of mycorrhizal fungi. When cut, the mushroom exudes a kind of milky liquid. This liquid may be orange, red, lilac, white or yellow, and may develop its final colour only after exposure to air. Certain ones, such as L. deliciosus are edible and delicious, appreciated in Mediterranean areas.

Other genera in the Russulaceae include Boidinia, Cystangium, Multifurca, and Pseudoxenasma.

Distinctive flesh consistency[edit]

Broken stem of Lactarius vellereus
Broken stem of Suillus variegatus

Due to the presence of large spherical cells which can be seen under the microscope, an important characteristic to distinguish the Russulaceae from other types of mushrooms is the consistency of the stipe. In Russula and Lactarius, this breaks like the flesh of an apple, whilst in most other families it only breaks into fibres. The pictures compare the broken stipe of a Lactarius vellereus, with that of Suillus variegatus, a member of the Boletaceae.

Parasites[edit]

Members of both Lactarius and Russula are subject to parasitization by the Lobster mushroom (Hypomyces lactifluorum). This ascomycete replaces the flesh of the host mushroom, rendering it into a choice edible, though it can be peppery if the host is a species like Lactarius piperatus.

References[edit]

  1. ^ Kirk PM, Cannon PF, Minter DW, Stalpers JA. (2008). Dictionary of the Fungi. (10th ed.). Wallingford: CABI. p. 609. ISBN 978-0-85199-826-8. 

External links[edit]