74 A Mo^'OGRAPH of the Erysiphaceae 



was very perceptibly greater on the treated plants/' In a series 

 of experiments, on a large scale, carried on by Close (72) the 

 same fungicide was found the most effective. The potassium 

 sulphide solution here used was of the strength of one oz. to two 

 gallons of water. Spraying should be begun very early, just as the 

 buds are breaking, and continued at intervals of about ten days. 

 It was found that English van:;ties and their seedlings were, as a 

 rule, more subject to attack than the American varieties. 



The gooseberry disease caused by .S". mors-nvae is confined to 



North America; the disease^ called in Europe the '^ gooseberry 

 mildew," is due to the attacks of Microspliaera grossulariae and is 

 not so dangerous, as it attacks only the leaves of gooseberry 

 bushes. 



4, S. LANESTRis Harku. 



S. lancstris Harkn. Bull. Cahf. Acad. Sci. i: 40. 1886; 

 Sacc, Syll. Fung. Addit. ad Vols. I-IV: i. 1886; and 9: 364. 

 1 891 ; Burr.; Ell. and Everh. N. Amer. Pyren. 9. 1892. 



Albigo lancstris (Harkn.) O. K. Revis. Gen. Plant. 3^: 442. 

 1892. 



Exsicc: Ell. .and Ev^erh. N, Amen Fung. sec. ser. 1537; 



Rab.-Wint. Fung. Eun 3240; * Seym, and Earle, Econ. Fung. 



188. 



Hypophyllous ; mycelium persistent, 'w^hen mature more or 

 less covering the under surface of the leaf, and composed of a 

 compact rather dense mass of much-branched, very tortuous, in- 

 terwoven, brown hyphae, which are thick-walled, or more or less 

 solid through the obliteration of the lumen ; perithccia gregarious, 

 imbedded in the persistent mycelium, subglobose, 80—120 n in 

 diameter, cells of outer wall obscure, irregularly shaped, 10—20 /^ 

 wide, inner wall becoming completely free from the outer, 

 formed of sirb-hexagonal colorless cells with refractive walls, about 

 1 5 IX wide ; appendages very short or obsolete, often entirely ab- 

 sent ; ascus large, from elliptic- to broadly-oblong, more or less 



distinctly stalked, 100-130 x 60-75 l^\ spores 8, 24-30 x 18 



20 a. 



Hosts,— Querc lis agrifoUa^ Q, alba (12) (361), O. niacrocarpa, 

 Q. miHoy {^i6i), Q, Prinns, Q. rubra (361). 



Distribution, — North America : United States— Alabama, 

 Illinois! Mississippi (361), Missouri! Iowa (361), California! 



