284 



Mycologia 



On PiNACEAE. Type collected on Pinus virginiana Mill, at 

 Glen Echo, Maryland, May 5, 1907, by Miss V. K. Charles. 

 Also collected in same locality on same host June 16, 1912. This 

 species is intermediate in its characters between Peridermium 

 delicatulum Arth. & Kern and Peridermium montanum Arth. & 

 Kern, but differs from the former in its more prominent aecia 

 and in its overlapping and oblong-lanceolate peridial cells and 

 from the latter in the size of the peridial cells and in the shape 

 and size of the aeciospores. 



The peridia of this species are very fragile, so much so that the 

 herbarium specimens collected in 1907 have entirely lost their 

 peridia, and in the field they soon fall away, making the aecia 

 inconspicuous. In this condition they much resemble Perider- 

 mium delicatulum' but a microscopic examination readily shows 

 that the peridial cells distinctly overlap and are not isodiametric 

 but are much longer than broad. This seems to be the first 

 foliicolous species of Peridermium reported for this host. The 

 type material was collected from a tree about four feet tall, and 

 was fairly abundant on this one plant. This season (1912) a 

 careful search was made over the same locality from which the 

 type was collected, but only five affected needles were found, 

 and then only one or two to a tree. 



Office of Investigations in Forest Pathology, 

 Bureau of Plant Industry, 

 Washington, D. C. 



