668 THE FUNGI WHICH CAUSE PLANT DISEASE 



Conidia cylindric or cuboid 

 Hyphse nearly obsolete; conidia cylin- 

 dric 10- Cylindrium. 



Hyphse distinctly present 



Conidia cylindric H- Polyscytalum. 



Conidia cuboid 12. Geotrichum. 



Oospora Wallroth (p. 567) 



Fertile hyphse short, sparingly branched, 

 slender; conidia catenulate, globose to ovoid, 

 hyaline or dilute-colored. 



Over one hundred species, chiefly saprophytes. 



O. scabies Thax.""- 2". 219-224 



Vegetative hyphse rarely 1 ju thick, curved ir- 

 regularly, septate or falsely septate, branching; 

 aerial hyphse at first white, then grayish, 

 evanescent, breaking up into bacteria-like 

 spores. 



Isolation and inoculation in pure culture by 



Thaxter showed this to be the cause of the 



Fig. 3S2.— Oospora. common American form of scab of Irish potato. 

 After Saccardo. , , , . , 

 beet, turmp, etc. 



O. abietum Oud. causes defoliation of firs in Europe.*^* 



Fusidium Link (p. 567) 



Hyphse short, simple, not well differentiated from the conidia 

 which are fusoid, catenulate, acute at the ends, hyaline or dilute- 

 colored. In part =Nectria. See p. 201. 



A poorly understood genus of over 50 species. 



F. candidum Link, on various trees =Nectria ditissima. See 

 p. 203. 



Monilia Persoon (p. 567) 



Hyphse erect, branched, forming a dense mycelial felt, which 

 produces numerous conidiophores; conidia catenulate, hyaline or 

 light-colored, ovate or lemon shaped. In part=Sclerotinia. See 

 p. 136. 



Some fifty species. 



