Pound and Clements: north American hyphomycetes. 671 



40. PERICONIA Tode. Fung. Mecklenb. 2: 2. 1791. 

 Vegetative hyphae creeping, generally obsolete; sporophores 



simple, fuscous; conidia borne upon denticulations or short 

 sterigmata at and near the apex in a dense head. 

 7 species are reported from the United States. 



41. C AMPTOUM Lk. Sp. PI. 1 : 44. 1824. 



Vegetative hyphae obsolete; sporophores simple, hyaline 

 with fuscous bands at regular intervals, at and near the apex 

 verrucolose-sporigerous; conidia fuscous, boat- shaped, curved 

 or inequilateral. 



1 species is reported from the United States. 



42. OEDEMIUM Lk. Sp. PI. 1 : 42. 1824. 



Sporophores erect, rigid, opaque, simple or sub-simple, at 

 the apex or laterally here and there bearing rather large, sub- 

 globose swellings; conidia globose, pleurogenous upon the lat- 

 eral or apical swellings. 



2 species are reported from the United States. 



Tribe Polyactitleae (Corda.) 



Polyactidei Corda. Prachtfl. 33. 1842. 



Sporophores erect, light-colored or grayish, very long, much 

 branched; branchlets obtuse or inflated near the apex, bearing 

 simple, single conidia in dense capitula. 



The conidia are sessile pleurogenous or borne on denticula- 

 tions at or near the tips of the branchlets. 



43. POLYACTIS Lk. Obs. Myc. 1 : 14. 1809. 

 Sporophores grayish or fuscescent, rather rigid, the branch- 

 lets thickened towards the tip, but not lobed or much swollen, 

 the thickened portion denticulate; conidia racemose upon the 

 denticulations. 



About 10 species are reported from the United States. 



44. PHYMATOTRICHUM Bon. Handb. Alg. Myk. 116. 1851. 

 Sporophores hyaline or light-colored, the tips of the bran- 

 ches inflated and somewhat lobed or crenate or digitate with- 

 out inflation; conidia borne in heads upon the denticulate or 

 muriculate lobes and inflations. 



4 species are reported from the United States. 



