76 MISSOURI BOTANICAL GARDEN. 



ing 3.5/* by 1.5/t. They are hyaline and germinate termi- 

 nally. 



The perithecia are smaller than those of C . exigua, the 

 description of which follows; the ascospores differ in shape, 

 and are smaller, and the terminal bristles of the beak have 

 a different shape, being short and thick as compared with 

 the slender ones of C. exigua. 



Ceratostomella exigua n. sp. 



The wood of dead and dying trees of Pinus Virginiana 

 Mill., and one or two other species, is often colored a blue- 

 black color, even more intense than that produced by Cer- 

 atostomella pilifera in wood of the western yellow pine. 

 Specimens were first obtained for study from Dr. A. D. 

 Hopkins of the United States Department of Agriculture. 

 It was at first thought that the stain was caused by C piti- 

 fera, but pure cultures of the fungus proved that it was 

 different in a number of particulars. The scanty mycelium, 

 the numerous diminutive perithecia and tbe smaller coni- 

 dia, as well as the more intense color of the stain, were 

 prominent points of difference which were considered of 

 specific importance. These characteristics remained quite 

 constant through a series of cultures on various kinds of 

 wood. 



The life history of the fungus obtained from a series of 

 pure cultures is as follows : — 



Mycelium. 



Cultures grown on pine decoction agar from both conidia 

 and ascospores give in a short time colonies with a white 

 mycelium much more limited in growth than that of C. pili- 

 fera. The conidial stage appears after 24 hours, and is 

 of the same type as that of C. pilifera x but with the con- 

 idia in lesser numbers. In a few days the perithecia ap- 

 pear on a mycelium which assumes a very dark brown, 



