6 



S. Castaynei in published lists. Tin- first named hosts are those upon 

 which the parasite has been considered distinct by Earle and the 

 writer; the others arc given upon the authority of the authors quoted. 



The distinction between the two species in question is, however, 

 apparently real in the fact that the characteristically large, irregular 



cells of the wall of the perithelium of S. Casfagnei are not found in 

 those called S. Ilumuli, and the sporidia of the latter constantly 

 average larger than those of the former. The difference also in the 

 appendages seems to indicate specific distinction. Tulasne's figure 

 (Select Fung. Carp. I, tab. IV, fig. 9) clearly shows these peculiarities 

 of S. Ilumuli, the name then used for the fungus. The much more 

 abundant mycelium of S. pannosa, and the smaller appendages suffi- 

 ciently separate that from S. Ilumuli, though the affinities appear to 

 be quite as close here as between the latter and S. Castagnei, with 

 which only our plant has been confounded. 



This is a very destructive parasite, especially on cultivated hops, 

 in the Old as well as in the New World. On raspberries it also does con- 

 siderable damage, though in many cases only the conidia are produced. 



On Geranium maculatum the cells of the wall of the perithecium 

 vary much, even in the same mount under the microscope, but the spo- 

 ridia and other characteristics are those of S. Ilumuli. 



S. pannosa, (Wallr.) 



Alphitomorpha pannosa, Wallr. Verhand. d. Naturf. Freunde, I, p. 43. 

 Erysibe pannosa, L,k. Species Plant. VI, I, p. 104. 

 Eurotium Rosarum, Grev. Seott. Crypt. Fl. Ill, p. 164, fig. 2. 

 Sphcerotheca pannosa, Lev. Ann. Sci. Nat. XV, p. 138. 



Mycelium abundant on the leaves, stems, etc., often sterile. Peri- 

 thecia more often occurring on the branches, scattered, delicate, 90- 

 100 p., reticulations evident, small, 10-15 /*; appendages short and 

 delicate, much interwoven with the mycelium, sometimes colored. 

 Ascus large, delicate, ovate, expanding, when free from the perithecium. 

 to a length greater than its diameter. Sporidia 8, large, 29 fx long. 



On Rosa blanda, R. Arhansana, R. lucida, R. humilis, R. 

 parmflora. Rather common from New England to California (Hark- 

 ness), and Texas (Jennings). 



Winter (Die Pilze, II, p. 26) and Saccardo (Syll. Fung. I, p. 2) 

 describe this species with hyaline appendages; but Tulasne (Select- 

 Fung. Carp. I, p. 208) describes them as colored. They frequently 

 are colored in our specimens. De Bary (Morph. und Phys. der Pilze, 

 II, p. 48) says "colorless or brown at base." 



S. Mali, (Duby). 



Erysiphe Mali, Duby Bot. Gall. p. 869. 



Sphcerotheca leucotricha, E. & E. Jour. Myc. IV, p. 58. 



Sphcerotheca Mali, Burrill, (this publication). 



Amphigenous. Mycelium white, submembranaceous, persistent 



