264 THE FUNGI WHICH CAUSE PLANT DISEASE 



Spores 2 or more-celled 

 Asci 8-spored 



Spores elongate, 2 to 4-celled 9. Griomonia, p. 274. 



Spores fusiform, curved, 2-celled 10. Hendersonia. 



Asci many-spored; spores elongate, 

 2-celled 



Perithecia beaked 11- Rehmiella. 



Perithecia not beaked 12. Rehmiellopsis, p. 276. 



Ditopella de Notaris (p. 263) 



Perithecia corticolous, covered, globose or somewhat depressed, 

 ostiole suberumpent; asci subclavate, polysporous; spores oblong 

 or fusoid, continuous, subhyaline; paraphyses none. 



D. ditopa (Fr.) Schr. causes death of oak twigs in Europe; 



D. fusarispora d. Not., occurs on alder in Europe. 



Glomerella Spaulding & von Schrenk^^. ^42 (p_ 263) 



Perithecia cespitose, membranous, dark brown, rostrate, of a 

 lighter color at the apex in early stages, flask-shaped, hairy, on 

 or immersed in a stroma; asci sessile, clavate; spores 8, hyaline, 

 oblong, 1-celled, slightly curved, elliptic; paraphyses usually none. 

 Conidia=in part CoUetotrichum and Glceosporium. 



This genus was first described by Stoneman, from perithecia 

 obtained from cultures of the conidia,''*' as Gnomoniopsis. On ac- 

 count of preoccupation it was renamed Glomerella by Spaulding and 

 von Schrenk ^^ in 1903. Studies by Shear have shown that there 

 is much variation in pure line cultures both from ascospores and 

 from conidiospores.^^' This leads to great uncertainty as to spe- 

 cific limitations as will become apparent in the paragraphs below. 

 The conidial forms are very common and are usually parasitic. 

 The ascigerous stages are comparatively rare. Sometimes they 

 are found in nature; again only ia artificial culture. Some forms 

 known to be ascigerous may in one culture yield abundant peri- 

 thecia while other cultures of the same fungus may persistently 

 refuse to bear asci at all. 



G. rufomaculans (Berk.) S. & S.^^^*' 



Perithecia on decaying fruits, subspherical, more or less grouped; 



