186 Journal of Mycology [Vol. 13 



The structure of the fungus causing this new disease of 

 vetch is very interesting. It resembles that of species of Corti- 

 cium. The basidia form a definite hymenium which is seated on 

 the pseudo-parenchymatous subhymenium, which is two or three 

 cell-layers in thickness. The nourishing mycehum extends out 

 into the surrounding tissue of the host. The spores are sessile ; 

 and are borne on a basidium in a whorl or crown at the end. 

 The spores are oblong to subelliptical, straight or curved, con- 

 tinuous, hyahne, granular, and measure 12-20x3-3.5 P- ^'^ the 

 spores fall away from the basidia others are produced as shown 

 by cultures. Conidia similar to the basidiospores are produced 

 on slender conidiophores which are intermingled with the basi- 

 dia. This character recalls that of the genus Exobasidium. The 

 spores also bud in yeast-like fashion from one or both ends, 

 rarely from the side, and the sporidia thus produced are similar 

 to the spores. 



The fungus appears to be the type of a new genus for which 

 the name Protocoronospora is proposed, and a provisional diag- 

 nosis is given as follows : 



Protocoronospora Atkinson and Edgerton new genus. 

 Stroma pseudoparenchymatous, two or three cell layers in thick- 

 ness, formed by the compact branching of the mycelium, the ulti- 

 mate exterior branches producing the basidia which form a hy- 

 menium. Spores sessile, hyaline, colorless, continuous, smooth, 

 several (usually four-eight) on a basidium. Spores budding and 

 forming sporidia similar in form. Conidia also similar in form 

 on slender short conidiophores intermingled with the basidia. 



P. nigricans Atkinson and Edgerton n. sp. — Forming 

 narrow elongated spots on the pods, stems, leaves and bracts, 

 spots oblique on the pods and from 2-5 mm. to 1-2 mm. Spots 

 at first white or with purple border, later black. Stroma sub- 

 epidermal, of pseudoparenchymatous cells 6-9 jx in diameter, two 

 to three cell layers in thickness. Basidia clavate to subcylin- 

 drical, 20-30 x 6-8 /x, 4-8 spored. Spores sessile, and basidia con- 

 tinuing to form new spores, at least in artificial culture. Spores 

 pale pink in mass, oblong to sulx^lliptical, hyaline, continuous, 

 smooth, granular, straight or curved, 12-20x3-3.5 /^^ usually be- 

 coming once septate on germination. Mycelium from the stroma 

 penetrating the adjacent tissues. Parasitic on pods, stems, leaves 

 and bracts of Vicia sativa. 



Botanical Department, Cornell University. 

 September 2, 1907. 



