214 MICROSCOPIC FUNGI. 



Melampsora Tremulse, Tul. Hypophyllous ; sori of 

 summer spores punctiform, prominent, or papillseform, numerous ; 

 spores tawny-yeilow, elliptical or obovate ; paraphyses slender ; 

 sori of perfect spores scattered, at length blackish; spores 

 elongated, compressed, attenuated downwards, yellowish. — On 

 leaves of Populus tremula. Common. Spores perfected during 

 the winter. 



Melampsora Betulina, Desm. Hypophyllous ; sori of 

 summer spores bright yellow or orange, oblong, cylindrical, or 

 obovate, truncate at the base, echinulate ; paraphyses encircling 

 or intermixed, obovate, smooth, hyaline ; sori of perfect spores 

 confluent, of an obscure brown in the winter, becoming of a bright 

 orange when mature ; spores elongated, attenuated below, poly- 

 gonal, ochraceous. — Onledives of Betula alba. Common. Spores 

 perfected in January and February. (Plate IX. figs. 189, 190.) 



Melampsora Salicina, Lev. Epiphyllous or hypophyllous ; 

 sori, or heaps of summer spores, scattered, pale orange, bright 

 orange, or cmereous ; spores ovato-globose, paraphyses capitate, 

 rarely obovate ; sori of perfect spores epiphyllous, scattered or 

 aggregate, at first yellowish-tawny, then brownish, at length 

 nearly black, bullate ; spores oblong, closely packed, and laterally 

 compressed. — On Salix vimlnalis and S. caprrpa. Common. Spores 

 perfected in February. (Plate IX. figs. 191, 192.) 



Cystopus. 



Beceptacle consisting of thick branched threads ; conidia con- 

 catenate, ^ at length separating ; oospores deeply seated on 

 the mycelium. 



Cystopus eandidus, Lev. CnucirEii White Rust; 

 conidia equal, globose ; membrane equal, ochraceous ; oospores 

 subglobose, epispore yellowish-brown, with irregular obtuse 

 warts ; warts sohd.-— On Shepherd's-purse, Cabbages, and other 

 Cruciferse. Summer. Very common. (Plate X. figs. 198— 200, 

 205-207.) 



Cystopus cubicus, Str. G9ATSBEAI1D White Rust; 

 conidia unequal ; terminal cell sterile, larger than the rest ; 

 membrane thickened, ochraceous, rarely yellowish ; fertile cells 

 shortly cylindrical; membrane hyaline; oospores globose ; epispore 

 brown, verrucose ; warts hollow, round, or irregular.— On goats- 

 beard, salsify, and scorzonera. Summer and autumn. Common. 

 (Plate X. figs. 201, 202, 210.) 



Cystopus Lepigoni, De By. Sandwort White Rust; 

 conidia unequal ; terminal cell sterile, globose ; membrane 

 thickened; fertile cells subglobose or cylindrical; membrane 

 hyaline ; oospores globose ; epispore brown, tubercles minute, 

 irregular, very convex, often resembling spines.— On Spergularia 

 rubra, Swanscombe Marshes, September, 1864;. (U. G. Keeley.) 



