Agaricus bitorquis

SPECIES Agaricus bitorquis (Quel.) Saccardo = Agaricus rodmanii Peck = Agaricus campestris var. eduiis Vitt. 

STRAINS Horst B30 (The first commercial strain to be developed by Gerda Fritsche at the Dutch Mushroom Research Center in Horst, Holland). 

Horst K26, K32 (These are two second generation strains from Horst B30 and are distinotive from it in that they fruit earlier, give higher yields and have slightly longer stems. Spawn of this species is now available from Amycel.) 

GENERAL DESCRIPTION Cap smooth, white, thick fleshed, convex to broadly convex to plane with age. The cap margin is incurved at first but soon decurves. The gills are pinkish at first, soon darkening to chocolate brown with spore maturity. The stem is thick, relatively short and adorned with a double membranous annulus. (The lower ring is often a thin annular zone). Its spores are dark chocolate brown In mass. 

NATURAL HABITAT Naturally found In lawns, gardens, roadside areas, pastures, in enriched grounds and on hard packed soil. A temperate species, widely distributed, A. bitorquis fruits primarily In the spring and To a lesser degree In the fall. 

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Agaricus bitorquis) also causes hypersensitivity pneumonitis, but basidiospores of Agaricus are usually not involved in these cases. 

Figure 38 Hyphal aggregates oi Agaricus bitorquis forming on malt agar media.

Figure 144 Linear (longitudinallv radial) mycelium of Agaricus bitorquis.

P.J.C. Vedder 1978, "The Cultivation of Agaricus bitorquis m The Biology and Cultivation of Edible Mushrooms ed. by Chang and Hayes. Academic Press, New York. 

Van Zaayen (1979) and others have noted Agaricus bitorquis seems resistant to virus disease even when inoculated with in vitro particles. Another species of Agaricus, called Agaricus arvensis, exhibits similar virus resistant qualities. 

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