THE FUNGI WHICH CAUSE PLANT DISEASE 645 



It is the cause of a dry rot of apples.^*' '" 

 V. dianthi (Hal.) Atk." 

 It is the cause of anthracnose of carnation. 

 The acervuli are conspicuous with black setae. 

 V. concentrica Hals, is reported by Halsted as the cause of leaf 

 spots of Bletia."^ 



TuberculariaceaB-Mucedineae-Phiigmosporae (p. 638) 



HyphaB hyaline; conidia 2 to several-septate, hyaline or bright- 

 colored, fusoid to falcate, rarely short and simple in some species 

 of Fusarium. 



Key to Genera of Tuberculariacese-Mucedineae-Phragmosporte 



Conidia somewhat catenulate, cylindric. ... 1. Discocolla. 

 Conidia rarely catenulate 

 Conidia cruciately 4-celled; sporodochium 



gelatinous 2. Sarcinodochium. 



Conidia not cruciate 

 Conidiophores short, simple 

 Conidia very large, terete-oblong. . . 3. Bactridium. 



Conidia dolifonn 4. Pithomyces. 



Conidiophores more or less branched 

 Conidiophores dichotomous; conidia 



key-like 5. Heliscus. 



Conidiophores usually verticillately 

 branched, conidia usually fal- 

 cate, sometimes oblong 



Sporodochium gelatinous 6. Pionnotes, p. 645. 



Sporodochium waxy or byssoid ... 7. Fusarium, p. 646. 



Pionnotes Fries 



Sporodochium gelatinous, then firm, orange, pulvinate or lobed; 

 conidiophores fasciculate, simple or branched; conidia rather large, 

 fusoid to cylindric, curved. 



Only twelve or fifteen species, chiefly saprophj^es. 



P. betse Mas. occurs on mangels and beets and according to 

 Massee is probably identical with P. rhizophila which attacks 

 stored Dahlia roots and potatoes. 



