226 THE ASCOMYCETES 



siibcincta and Fhyllosticta phase olina, but Harter showed that 

 this stage properly belongs with Phomopsis, since both ellipsoidal 

 conidia and stylospores are produced. 



Diaporthe sojae was found bv Lehman (1923) to be seed-borne 

 and to involve leaves, pods, and stems of soybean. Its ascigerous 

 stage has been developed in pure culture. 



Valsa leiico St 0777a produces its stromata within the bark of the 

 trunk and twigs of stone fruits. The stromata protrude at ma- 

 uirity and in coming to the surface cause the host to appear 

 silvery. Rolfs (1910) found that this organism attacks trees 

 weakened bv freezing, bv drought, and by lack of an adequate 

 supply of minerals. 



Although numerous reports of studies of Endothia parasitica 

 have been published, adequate acquaintance with this organism 

 can be gained by perusal of those by Anderson (1914), Ander- 

 son and Rankin (1914), and Shear, Stevens, and Tiller (1917). 

 This organism was described as Diaporthe parasitica by Murrill 

 in 1906, although Alerkel reported its presence in New York 2 

 years earher. In 1913 the plant explorer Aleyer found it in 

 northern China, whence it had probably been imported to the 

 United States. 



Endothia parasitica causes the formation of cankers on twigs, 

 larger branches, and trunk. The mycelium spreads within the 

 cambium of these parts, girdling and killing them. The pycnidia 

 arise from a loose tangle of hvphae, the central branches of \\'hich 

 become conidiophores. This hyphal mass becomes stromatic, 

 and pycnidia are produced near the surface. Conidia are ex- 

 truded in tendrils if moisture is present. The perithecia form 

 from more deeply seated parts of the same stromata. First there 

 is a coiled ascos^onium with a functionless trichooryne. Around 

 this ascogonium are enveloping hvphae, whose cells are deeply 

 staining. These enveloping hyphae produce the perithecial loc- 

 uli, the innermost of which nourish the developing asci. De- 

 tails re^ardin^ fertilization are unknown. 



The taxonomic monograph by Wehmever (1933) is a basis 

 for study of the Genus Diaporthe; that by Shear, Stevens, and 

 Tiller (1917), for study of Endothia. The closely related genera 

 Melanconis, Pseudovalsa, Prosthecium, and Titania are taxonom- 

 ically treated by Wehmeyer (1941). 



