Pound and Clements : north American hyphomycetes. 737 



20. MYROTHECIUM. Tode. Fung. Meckl. 1 : 25. 1790. 

 Sporodochium disciform, or patellate, margined with thin, 



hyaline, continuous hyphae, similar to the sporophores; the lat- 

 ter usually branched, rarely bacillar; conidia oblong to cylin- 

 drical, simple, fuscous, often nearly hyaline. 



This genus contains 4 American representatives. 



Tribp Fusarieae. 

 Sporodochia pulvinate, verruciform, or sub-effuse, not setose 

 or ciliate; conidiophores verticillately branched; conidia acro- 

 genous, oblong, ovoid, f usoid, or falcate, continuous or septate. 



21. DENDRODOCH1UM. 



Sporodochia pulvinate or verruciform; conidiophores sub 

 verticillate; conidia elliptical or oblong, continuous. 



This genus connects with Knyaria on the one hand and with 

 Fusarium on the other. Six species are reported for North 

 America. 



22. FUSARIUM Lk. Berl. Mag. 3: 10. 1809. 



Including Fusisporium Lk. Obs. Myc. 1:17, and Selerosporium 

 (Jokda. 



Sporodochia pulvinate, or effused; conidiophores verticil- 

 late; conidia f usoid or falcate, continuous or, usually, many- 

 septate. 



In Eu-Fusarium the sporodochia are pulvinate, while in Fusis- 

 porium they are effuse and are scarcely to be termed sporo 

 dochia. The latter is in many respects allied to Trichoderma, 

 near which it was long placed. Bat it has been shown that the 

 same species may assume either the pulvinate or the effuse 

 type under varying conditions, thus rendering it practically 

 impossible to maintain a distinction. 



Fifty-six species are described or reported from North 

 America. 



23. PIONXOTES Fr. Summ. Veg. Scand. 481. 1849. 

 Sporodochia gelatinous, becoming rigid, forming a thick, 



often lobed, mass; sporophores subverticellate, sometimes sim- 

 ple, fasciculate; conidia rather large, elliptical, cylindrical, or 

 usually fusoid, curved, continuous or obsoletely septate. 



Not very well distinguished from Fusarium. 2 species are 

 reported for North America. 



