Russula AGARICACE^E 28 1 



somewhat separable, margin membranous, at first convergent 

 and not involute, in full grown plants commonly sulcate 

 and tubercular, not striate in 1348, 1356 and 1363. Stem 

 spongy, at length wholly soft and hollow. Gills almost all 

 equal, simple, broadening in front, free. Flesh commonly 

 floccose, lax, friable. Several doubtful forms occur; 1357 

 is specially variable in colour. 



Gills and spores white. 1347 — 1355 



Gills and spores white, then bright lemon-yellow. 1356 — 1361 

 Gills and spores ochreous. 1362 — 1369 



a. Compacted. 



1306. R. nigricans Fr. (from its changing to jet-black in decay; 



nigricans, becoming black) a b c. 

 P. convex, depressed; streaky umber-tan, sometimes olive- 

 shaded ; mid. almost black. St. attenuate downwards, sienna- 

 tan, steel-greyish or faint purplish. G. rounded-adnexed, very 

 thick, distant, pale yellowish. Flesh white, then reddish or 

 pale purplish, at length black. 



Odour none. Woods, mixed, etc. ; common. June-Nov. 5^ X i\ X 2 in. 

 Becoming wholly black and in this character analogous with 1221. 

 1389 grows on decaying examples of this species. 



1307. R. adusta Fr. (from its scorched appearance ; adustus, 



scorched) a b c. 

 P. convex to depressed or subinfundibuliform, smooth, whitish to 

 pallid yellowish, at length clouded olive-sepia. St. equal, 

 colour as young P. G. adnate to decurrent, thin, crowded, 

 white then dull. Flesh unchangeable or becoming grey or 

 pale sooty. 



Taste mild to acrid. Woods ; frequent to rare, local. Aug.-Oct. 

 3l X 2| X l| in. Not becoming wholly black. 1390 grows upon this 

 species and on 1341. Var. ccernlescens Fr. becomes blue when broken 

 or cut. 



1308. R. albonigra Fr. (from the colours ; aldus, white, niger, black) 



a b. Very rigid. 



P. convex to infundibuliform, viscid, whitish ; marg. smoky. 



St. dusky, or white above, pale grey-ochreous towards base, 



spotted-sooty. G. decurrent, crowded, thick, unequal, 



connected by veins, dimidiate, dusky whitish or yellowish. 



Flesh white, then black or sooty, not red. 



Taste somewhat acrid and unpleasant to mild ; odour none. Grassy places 

 under trees. Aug. 3§ X ifx ig in. 



1309. R. densifolia Cooke (from the crowded gills, as compared 



with 1306; densus, thick, folium, a leaf) a b. 

 P. convex to depressed, smooth, whitish, becoming streaky- 

 fuliginous, grey or brownish ; mid. black. St. smooth, whitish 

 to grey, then blackish. G. adnato-decurrent, unequal, thin, 



