KEYS TO THE MORE IMPORTANT GENERA OF FUNGI IMPERFECTI 617 



Main axis of conidium slender, with two lateral branches diverging at 

 the same level from the convex side of the curved axis, the two 

 branches and the lower and upper portion of the axis forming a four- 

 armed spore; a short "separating cell" present at the upper end of 

 the conidiophore. Tetrachaetum 



Main axis of the conidium stout, septate, curved, the usually two eventu- 

 ally septate branches arising from adjacent cells of the axis or at 

 opposite ends of the same long cell. Tricladium 



Main axis of the conidium septate, curved, bearing from separate cells 

 on the convex side several branches approximately in the same plane; 

 these may also produce lateral branches, the whole spore resembling a 

 character of Chinese writing; conidiophore slender, bearing one to 

 several conidia on its distal quarter. Varicosporium 



Main axis of conidium long and slender, much septate, straight, bearing 

 from the cells of the lower half one or more septate, lateral branches, 

 which in similar manner bear shorter lateral branches; main axis of 

 spore a continuation of the long, slender, septate conidiophore. 



Dendrospora 



Not all aquatic, producing the conidia in the air; saprophytes or parasites. 



Conidiophore slender, nonseptate, . bearing a single conidium with three 



cylindrical, septate arms, one of which is attached by its lower end to 



the conidiophore. Trinacrvum 



Conidiophore slender, nonseptate; conidia four- to five-armed, nonseptate, 



all but one or two tapering into slender bristles; parasitic on fungi. 



Titaea 

 Conidiophore long and slender, hyahne, septate, sometimes branched; 

 the single hyaline conidium inversely pyramidal, the lower part sep- 

 tate and tapering to the conidiophore, the broad upper portion with 

 four one- to two-ceUed conical arms. Parasitic on terricolous nema- 

 todes. 



Triposporina 

 Conidia colored. 



Conidia practically sessile, dictyosporous, at the apex with four long, septate, 

 cylindrical, spreading extensions. Saprophytic on herbaceous stems. 



Tetraploa 

 Conidia sessile, three to several radiate, the arms obclavate and septate, 



saprophytic on woody substrata. Ceratosporium 



Conidia sessile, horseshoe-shaped, therefore two-armed, multiseptate; para- 

 sites. Hirudinaria 

 (The systematic placing of the three foregoing genera is very uncertain.) 

 Conidiophores elongated, upright, septate; the single terminal conidium with 

 a short axial cell from whose top radiate horizontally three septate 

 arms tapering to a blunt apex. Saprophytic on woody or herbaceous 

 stems or parasitic on leaves. Triposporium 

 Conidia of two kinds, usually arising from a small dark-colored sporo- 

 dochium: (1) long-stalked conidiophore bearing at its apex four spiny 

 cells, the attachment at the center where the cells meet; (2) four- 

 celled, smooth spores, attached by the edge of one cell to the short 

 conidiophore. The latter kind of spore and the sporodochium are 

 apparently lacking in some species. Saprophytic on dead herbaceous 

 leaves or stems, one species possibly parasitic on leaf fungi. 



Spegazzinia 



