188 



fected the spots are occasionally confluent. Usually there are only a few- 

 spots on a leaf. 



Etiology. — The fungus gives rise to numerous acervuli, which are dark 

 brown or black, irregularly scattered, varying greatly in size (50-200 

 microns). They are beset with dark brown seta?. The seta? are numerous, 

 arising from any part of the - acervulus. 1-4 septate, dark brown, sharp- 

 pointed, straight or slightly curved above the base. The base is usually 

 bent or curved in various ways. 



The spores are hyaline, non-septate, slightly curved averaging 4.5x25 

 microns. They are borne on short, hyaline conidiophores. In some cases 

 at germination a delicate septum was observed in the middle of the spore. 

 This is by no means always present. 



Nomenclature. — There has been, in the past, some confusion in regard 

 to the limits of the genera Colletotrichum, Vermicularia, Volutella aud 

 Chsetostroma. This has been due, largely, to the lack of care exercised by 

 investigators when species of these genera have been studied. Sections 

 carefully made clear up generic confusion very easily. The fungus de- 

 scribed above is undoubtedly a Colletotrichum since there is no pycnidinm, 

 the spores being borne on short conidiophores in a setose acervulus. 



In 1899, Dr. Ralph Smith' described a leaf spot of pansy caused by a 

 Colletotrichum. The type material of this fungus has been examined and 

 found to differ from the Colletotrichum under discussion in the size and 

 shape of the spores, the shape of the seta 3 and the character of the spot 

 produced. 



Dr. Peck- in 1S7S described a leaf spot of Viola rotund if olio as follows: 



"Vermicularia concentrica Peck and Clinton n. sp. Perithecia small, 

 black, beset with straight, rigid bristles, concentrically placed on arid, 

 orbicular spots ; spores oblong, slightly curved, pointed at each end, color- 

 less, .OOOS'-.OOl' long. 



"Living leaves of Trillium eriithrovarpum. Pine Valley, Clinton, July: 



"The tissues at length fall out from the affected spot, leaving apertures 

 through the leaf. The perithecia are less regularly disposed near the cen- 

 ter of the spots. Judge Clinton also sends a variety on the leaves of Viola 

 rotund if olia in which the concentric arrangement of the perithecia is not at 

 all preemptible, but I detect no other difference." 



(0 Botanical Gazette. 27: 203-204, Mar. 1899. 



( 2 ) Report of the N. Y. State Botanist 1878. 29th Annual Report of the N. Y. State Museum 

 of Natural History, pps. 47-48. 



