NYCTALIS PARASITICA 459 



Nyctalis parasitica. — Nyctalis parasitica (Fig. 190), although 

 resembhng N. asterophora in being parasitic on certain other agarics, 

 is quite distinct from that species. It is thus described by Rea : ^ 



" Pileus 1" 5-3 cm., ivhitish fuscous, then becoming pale whitish, 

 somewhat fleshy, conico-campanulate, then convex, plane, obtuse 

 or obsoletely umbonate, unequal, pellicle persistent, pruinose, grey. 

 Stipe 2-5-6 cm. X 2-4 mm., white, straight or curved, equal, or 

 slightly attenuated upwards, pubescent, bristling with hairs at the base. 

 Gills white, becoming fuscous, adnate, thick, distant, with alternate 

 shorter ones intermixed, at length contorted and anastomosing. Flesh 

 dark grey. Spores white, elliptical, 5-7 x 3-4 /a. Smell like Poly- 

 porus squamosus. On dead Russula adusta, Russula foetens, Russula 

 chloroides, and Lactarius vellereus. August-December. Common." 



Among the hosts of Nyctalis parasitica, in addition to those 

 recorded by Rea, are Lactarius blennius observed by Frics,^ Russula 

 delica observed by de Bary,^ and R. nigricans observed by Brefeld.* 

 Among the hosts which may be attacked by both Nyctalis astero- 

 phora and N. parasitica are : Russula adusta, R. nigricans, and 

 Lactarius vellereus. 



A photograph showing Nyctalis parasitica on Lactarius vellereus 

 is reproduced in Fig. 190. For coloured illustrations the reader is 

 referred to the works of Brefeld ^ and Cooke. ^ 



In the description of the fruit-body of Nyctalis parasitica given 



and a number (including many tropical forms) in which telia are not known. P-uccinia 

 Jridis {North American Flora, vol. vii, p. 379) is fairly common on Iris versicolor in 

 the eastern part of North America, and upon this host is only found in Ihe uredinial 

 stage ; upon other species of Iris west of the Rocky Mountains telia may be found. 

 P. epiphylla {ibid., p. 327), in North America, produces telia and aecia only in alpine 

 and boreal stations, although the uredinia occur almost throughout the continent. 

 P. Chrysanthemi {ibid., p. 508) is known over much of the world, but telia are known 

 only in Japan. The formation of the telia has been shown by Raines {American 

 Journal of Botany, 1922) to be partially at least a factor of the constitution of the 

 fungus ; he was able to select cultures of P. coronifera with small or with large 

 production of telia." 



1 Carleton Rea, British Basidiomycetae, Cambridge, 1922, p. 541. 



2 E. Fries, Systema Mycologicum, Gryphiswaldiae, 1821, vol. i, p. 136. 



3 A. de Bary, " Zur Kenntniss einiger Agaricinen," Bot. Zeit., Bd. XVII, 1859, 



p. 393. 



4 0. Brefeld, Untersncknngen iiber Pilze, Heft VIII, 1884, p. 71. 



5 O. Brefeld, ibid., Tab. VI, Fig. 1. 



6 M. C. Cooke, Illustrations of British Fungi, Plate 1113. 



