190 



DISEASES OF CULTIVATED PLANTS 



the form of miniature pins with pale yellowish heads, and 

 1-2 mm. high. 



During January 1908 a large consignment of diseased 

 berries was received at Kew from Costa Rica. The berries 



Fig. 50. -Sphaerostilbe fiavida. 1. leaf showing disease; 2, 



section showing conidia fi rm ; 3, mu fa< e \ iew ot w hite spot bear- 

 ing conidial stage of fungus; 4, section showing perithecia; 

 5, two perithecia; 6, ascus containing eight spores. Kig. 1 

 reduced ; remainder mag. 



had been carefully packed, and arrived in a good condition 

 for experimenting with. These were placed in Petri dishes 

 on sterilised damp blotting-paper. At the expiration of 

 seven weeks dense groups of minute, bright-red perithecia 



