The _genus Russula_ has been divided into the following tribes or groups:--Compactae, Furcatae, Rigidae, Heterophylla, and Fragiles. The species _Russula (Rigidae) virescens_, illustrated in Plate I, belongs to the tribe Rigidae. In the plants of this group, the cap is absolutely dry and rigid, destitute of a viscid pellicle; the cuticle commonly breaking up into flocci or granules; the flesh thick, compact, and firm, vanishing near the margin, which is never involute, and shows no striations. The gills are irregular in length, some few reaching half way to the stem, the others divided, dilated, and extending into a broad rounded end, stem solid. [Illustration: Plate I. RUSSULA VIRESCENS FR. (EDIBLE) The Verdette From Nature Collected in the District of Columbia Report of Microscopist, U. S. Department of Agriculture 1893 L. Krieger, Pinx. AVIL. CO. LITH. PHILA.] PLATE I. =Russula virescens= Fries. "_The Verdette_" _or_ "_Greenish Russula_." EDIBLE. The cap of this species is fleshy and dry, the skin breaking into thin patches. The margin is usually even, but specimens occur which show striations. The color varies from a light green to a grayish or moldy green, sometimes tinged with yellow; gills white, free from the stem or nearly so, unequal, rather crowded; stem white, stout, solid, smooth, at first hard, then spongy; spores white, nearly globose. One writer speaks of the "warts" of the cap, but the term warts, used in this connection, refers merely to the patches resulting from the splitting or breaking up of the epidermis of the cap, and not to such excrescences called warts, as are commonly observed on the cap of Amanita muscaria, for instance, which are remnants of the volva. The _R. virescens_ is not as common as some others of the Russulae, in some localities, and hitherto seems to have attracted but little attention as an edible species in this country, although highly esteemed in Europe. It has been found growing in thin woods in Maryland and in Virginia from June to November, and we have had reports of its growth from New York and Massachusetts. The peasants in Italy are in the habit of toasting these mushrooms over wood embers, eating them afterwards with a little salt. Vittadini, Roques, and Cordier speak highly of its esculent qualities and good flavor. We have eaten quantities of the virescens gathered in Washington, D. C., and its suburbs, and found it juicy and of good flavor when cooked. EXPLANATION OF PLATE I. Plate I exhibits four views of this mushroom (_R. virescens_) drawn and colored from nature. Fig. 1, the immature plant; Fig. 2, advanced stage of growth, cap expanded or plane; Fig. 3, section showing the unequal length of the gills and manner of their attachment to the stem; Fig. 4, surface view of the cap showing the epidermis split in characteristic irregular patches; Fig. 5, spores, white. AGARICINI.