Russula Notes

Russula

           

Scientific classification

Kingdom:       Fungi

Division:         Basidiomycota

Class:              Agaricomycetes

Order:             Russulales

Family:           Russulaceae

Genus:            Russula

Distribution:-

Russula brevipes is a species of mushroom commonly known as the short-stemmed russula or the stubby brittle gill. It is widespread in North America, and was reported from Pakistan in 2006. The fungus grows in a mycorrhizal association with trees from several genera, including fir, spruce, Douglas-fir, and hemlock. Fruit bodies are white and large, with convex to funnel-shaped caps measuring 7–30 cm (3–12 in) wide set atop a thick stipe up to 8 cm (3 in) long. The gills on the cap underside are closely spaced and sometimes have a faint bluish tint. Spores are roughly spherical, and have a network-like surface dotted with warts. Russula crustosa, commonly known as the crusty russula, is a species of fungus in the family Russulaceae. It is found in Asia and North America.Rusula is also found in China, India, Malaysia, and Thailand.

General Features of Rusula:-

v  Russula emetica is characterized by having a red cap (pileus) in which the cuticle peels 1/3-3/4 of cap radius, a pure white stem (stipe), and a very acrid or peppery hot taste. 

v  All Russula and Lactarius species are mycorrhizal, which means they have a mutualistic association with the roots of trees, especially members of the oak family (Fagaceae) and pine family (Pinaceae).

v  There are hundreds, if not thousands of Russula species, most of which are not well characterized nor well delimited, mostly because they are obligate mutualists and cannot be cultured.

v  Most species are very difficult to identify. 

v  Russula  species are unique among mushrooms in that they contain sphaerocysts, a fancy name for spherical cells that in profile appear round. These sphaerocysts cause the members of these genera to be more fragile than "regular" mushrooms of the same size and stature.

v  Russula can be easily identified by the "drop-kick" method-- the mushroom should shatter into a million pieces if properly kicked. 

v  The species was first described scientifically by American mycologist Charles Horton Peck in 1886, who made the type collections in Day, New York.

v  The fruit bodies have caps that are initially convex before flattening out in age, often developing a central depression, and measure 5–12.5 cm (2.0–4.9 in) in diameter. 

v  An edible mushroom, R. crustosa has no distinguishing odor, and a taste ranging from mild to slightly acrid. Other greenish Russulas, including R. subgraminicolor, R. aeruginea, and R. variata, can be most readily distinguishing by their non-cracking cap surfaces.

v  Russula crustosa is commonly mistaken for Russula virescens, a more desirable edible mushroom that features greenish patches on its cap surface. 

Diversity of  Russula species with reference to Pakistan

Rusula nigricans                     Edible                          According to Gardezi et al 1993

Rusula virescens                      Food                            According to Gardezi et al 1993

Rusula chloroide                     Food                            Syed Riaz and Mahmood Khan 1999

Rusulla brevipes                      Edible                          According to FAO