182 THE ASCOMYCETES 



succeeding spring the perithecia are mature. Koch (1935) iso- 

 lated ascospores in culture and produced from them the Hormo- 

 dendrum stage. Farlow (1876) and Koch (1934) call attention 

 to an associated Coniothyrium (pycnidial) stage, which Koch 

 states is not genetically connected. Since details of the initiation 

 of ascocarps are lacking, this familiar organism should be rein- 

 vestigated. 



Phyllachoraceae. Phyllachora graininis and related species 

 on various grasses are the most' commonly encountered repre- 

 sentatives of this family. Phyllachora graininis produces its 

 stromata within the leaves of many grasses. It may prove to be 

 a composite of many species, but this hypothesis can be proved 

 only by comparative morphologic studies and by reciprocal cross- 

 inoculations. Phyllachora grajnwis has not been artificially cul- 

 tivated, does not possess a conidial stage, and has been stated to 

 have perithecial walls like those of the Sphaeriales. For this 

 reason Orton (1924) is of the opinion that all species of Phyl- 

 lachora and perhaps the entire family Phyllachoraceae should be 

 removed to the Sphaeriales. 



DoTHiDEACEAE. The several members of the Dothideaceae in- 

 vestigated include Systrevi7na iilmiy parasitic on elm, Cyiimdothea 

 trifolii, causing sooty blotch of clovers, and Systrejinna acicola* 

 the cause of brown-spot needle disease of pines. KilHan (1920) 

 found that ascospores of Systrenmia uhni initiate the primary in- 

 fections in the spring. As a result, a subcuticular stroma, from 



* The organism was given the name Scirrhia acicola (Dearness) by 

 Siggers in 1939 (Phytopatb., 29: 1076-1077, 1939), and this name is retained 

 by him in a later report {Tech. Bull. U. S. Dept. Agr., 810, 36 pp., 1944). 

 His photographs in Plate 1 are manifestly those of an immature stroma 

 (Fig. C) and immature ascospores (Fig. D). Mature stromata are exposed 

 and prominently protrude and hence (Fig. D) are not those of the 

 Phyllachoraceae. Discharged ascospores have brown walls as well as 

 brown cell content. The ascospores of the Genus Scirrhia, as delimited 

 and accepted, are colorless. In this connection it may be well to reflect 

 upon the fact that the conidia of the brown-spot fungus are brown-walled, 

 that the stromata (conidial, spermogonial, carpogonial, and perithecial) are 

 composed of brown-walled cells, and that the mycelium in culture is col- 

 ored and produces smokv to black colonies. WTiat, then, is the likelihood 

 of "uncolored" ascospores? It seems unthinkable that this brown-spot 

 fungus could be properly placed in the Genus Scirrhia. 





