FUNGOID PESTS OF CULTIVATED PLANTS. 195 



dilated and rounded. Only one ascus is contained in each receptacle, and 

 this encloses eight hyaline ovoid sporidia. 



This mildew is believed to be found over the whole of Europe, 

 extending into Algeria. Formerly known as Podosphcera clandestina. 



Sacc. Syll. i. 1 ; Cooke, Hdbk. No. 1917 ; Cooke, M. F. p. 239. 



HAWTHOBN CLUSTER-CUPS. 

 Rcestelia lacerata (Mer.), PL XVIII. fig. 38. 



It is usual in these days to call this species of fungus Gymnosporangium 

 clavariiforme, because it is believed to be the first stage, or cluster-cups, 

 of a gelatinous exudation from the branches of the common Juniper. 

 For our purpose it is better to continue to call it the Hawthorn cluster- 

 cups, and regard it as a disease of the Hawthorn. 



The leaves, and sometimes the fruits, are swollen in places, and from 

 these swellings burst out the tufts of cluster-cups, seated on orange spots. 

 The cups are at first flask-shaped, then cylindrical, and split nearly to 

 the base in reflexed filaments enclosing the chains of yellowish secidio- 

 spores, which are separately nearly spherical, compressed, angular 

 (22-45 x 10-35 /i), and warted. 



It is reported for France, Belgium, Germany, Finland, Austria, 

 Hungary, Dalmatia, Italy, and North America. 



Sacc. Syll. vii. 2606 ; Cooke, M. F. figs. 22-26 ; Cooke, Hdbk. No. 

 1599 ; Gard. Chron. 1861, p. 336 ; Sow. Fun. t. 318. 



LABURNUM LEAF-SPOT. 

 Phyllosticta Cytisi (Desm.), PL XVIII. fig. 39. 



Living leaves of Laburnum are subject to spotting from the attacks 

 of this parasite, which produces circular bleached spots, turning brown- 

 ish, but with scarcely a distinct margin. The receptacles are dot-like, 

 and scattered over the spots. Sporules oblong, rounded at the ends, 

 curved, containing one guttule (6 x3-4 yu). 



In addition to Britain this fungus is known in France, Belgium, 

 Austria, and Italy. 



Sacc. Syll. iii. 40 ; Cooke, Hdbk. No. 1847. 



Another spot, caused by an allied species (Phyllosticta laburnicola), 

 has been observed in Italy: There are no definite spots, and the sporules 

 are smaller (3-5 x 1 /*). 



Not an uncommon fungus on branches of Laburnum is Cucurbitaria 

 Laburni (Pers.), which has been claimed as a wound parasite, but it is 

 commonly seen on dead twigs. 



Hart. & Som. in Dis. Trees, p. 87 ; Sacc. Syll. ii. 3937. 



LABURNUM ANTHRACNOSE. 

 Glceosporium Cytisi (B. & Br.). 



This anthracnose was first recognised .by Berkeley on leaves of 

 Laburnum in Scotland, but does not appear to have spread southward. 



o2 



