234 THE FUNGI WHICH CAUSE PLANT DISEASE 



ing whitening of the mountain cedar (Sabina sabinoides) from 

 Texas to Central Mexico. The seat of infection is the younger 

 twigs and the young trees, especially where in shade. The disease 

 may kill the entire trees. 



Cucurbitariaceae (p. 222) 



Perithecia clustered, immersed at first, then erumpent, seated 

 on a stroma, leathery to carbonous; paraphyses present. The 

 species numbering about one hundred fifty are mostly saprophytes. 



Key to Geneba of Cucurbitaiiaces 



Spores l-celled 

 Asci 8-spored 



Spores large, green 1. Bizzozeria. 



Spores small, hyaline 2. Nitschkia. 



Asci many-spored 3. Fracchiaea. 



Spores 2 or more-celled 

 Spores 2-celled 



Perithecia bristly, spore walls hyaline . . 4. Gibbera, p. 234. 



Perithecia smooth, spore walls brown. . 5. Otthia. 



Spores more than 2-celled 6. Gibberidea. 



Spores murif orm 7. Cucurbitaria, p. 234. 



Gibbera Fries."' 



Perithecia cespitose on a superficial, thick, Demataceous, conidia- 

 bearing, carbonous, fragile, bristly stroma; ostiole papillate; asci 

 cylindric, 8-spored; spores oblong, elliptic, hyaline, uniseriate. 



The genus contains some half dozen species, one of which G. 

 vaccinii (Sow.) Fr. occurs on Vaccinium in Europe. The conidial 

 form is Helminthosporium vaccinii. Fig. 169. 



Cucurbitaria Gray 



Perithecia cespitose or more rarely gregarious on a crustaceous 

 stroma covered by Demataceous hyphae, spherical, glabrous, black, 

 coriaceous; asci cylindric, 8-spored; spores uniseriate, oblong or 

 elliptic, muriform, brownish, paraphyses present. 



