THE FUNGI WHICH CAUSE PLANT DISEASE 



209 



yellowish, cylindrical, slightly curved, discharged in twisted threads 

 as in Cytospora, 



This fungus, originally described as Diaporthe parasitica, is a 

 serious parasite on the chestnut. The mycelium grows through 

 the inner bark in all directions from the initial wound at which in- 

 fection occurred, eventually girdling the part. The wood is also 

 affected. The perithecia appear in abundance upon or in cracks 

 of the baxk, extruding their spores in greenish to yellow threads. 



Hypocrea Fries (p. 199) 



Stroma subglobose to patellate, fleshy or subfleshy; perithecia 

 entirely immersed, subglobose to ovate, the necks slightly pro- 

 truding; asci cylindric, originally 8-spored, spores breaking each 

 into two so that the asci at maturity contain sixteen hyaline 

 spores. About one hundred ten species. 



H. ceretriformis Berk, occurs on the bamboo in Tonkin; 



H. sacchari on sugar cane. 



Balansia Spegazzini (p. 199)'^^ 



Sclerotium composite, formed of the affected parts of the host 

 embedded in a well developed mass of fungous tissue; stroma 

 arising from the sclerotium, stipi- 

 tate and capitate or sessile, pul- 

 vinate, obovate, discoid, or sepa- 

 rated from the sclerotium as 

 soon as the latter is mature, sur- 

 face slightly papillate from the 

 projecting ostiola of the im- 

 mersed scattered perithecia; asci 

 8-spored; paraphyses none. Co- 

 nidia, when known, an Ephelis 

 and preceding the stroma. 



B. hjrpoxylon (Pk.) Atk. oc- 

 curs on various grasses, chiefly 

 in the southern United States, fig. i50, 

 B. claviceps Speg. infests Setaria 

 and Pennisetum in tropical lands. 

 The remaining species, chiefly of warm regions, are mostly grass 

 inhabiting. 



B. hypoxylon, section 

 pseudosclerotium and one stroma 

 showing perithecia, stem, leaf ele- 

 ments and an ascus. After Atkinson. 



