252 Journal oj Agricultural Research voi. iv, no. 3 



these fungi spread to the leaves of an adjacent tree which normally 

 is never selected as a host. This occurs when the branches and leaves of 

 the regular host are intermingled or in contact with those of the other. 

 The mycelium in such cases may be simply crowded over and may con- 

 tinue to draw its nourishment from its regular host. Instances of this 

 kind have been noted where H. nigra spread from Abies lasiocarpa 

 to Phyllodoce empetriformis (Smith) D. Don. Whether the mycelium 

 actually penetrates the tissues of the leaves of the borrowed host has not 

 been determined. The epiphytism of the fungus, however, is sufficient 

 to cause the death of the leaves covered by its mycelium. 



So selective are these two interesting fungi with regard to their hosts, 

 it has always been a field practice of the writer to refer them to their 

 respective genera by this fact alone. On the examination of several 

 collections of what seemed to be H. nigra on Picea engelmanni from 

 Marble Mountain, St. Joe National Forest, Idaho, it was found that 

 the fungus was not this species but another of the same genus. This 

 led to a further examination of the same material and also of other 

 collections from various regions of the West which were sent in from the 

 field labeled " Herpotrichia nigra." The fungus on a large part of these 

 collections on species of Picea w^as found to be quite different in its micro- 

 scopic characters from H. nigra. Although the gross appearance of 

 the mycelial mat was the same (PI. XXXIV, fig. 2), the mature spores 

 were uniformly 5-septate, and were scarcely constricted at the septa, 

 which were prominent and fairly thick (PL XXXIV, fig. i, C). A large 

 amount of material was examined, and the 5-septate spore was found 

 to be as characteristic a feature of this fungus as is the i -septate spore 

 for N. coulteri and the 3-septate spore for H. nigra. Mature apothecia 

 of all three fungi w^ere crushed together and mounted on the same slide. 

 Plate XXXIV, figure i, A, B, and C, are reproduced from camera-lucida 

 drawings of this material and show the proportionate size and character 

 of the asci and spores for all three species. 



Since the fungus originally collected on Picea engelmanni from Marble 

 Mountain, Idaho, does not agree with H. nigra Hartig or ^^'ith any other 

 known species, it is described as new: 



Herpotrichia quinqueseptata, n. sp. 



Perithecia gregarious or scattered, spherical, 0.19 to 0.43 mm. in diameter, par- 

 tially embedded in a dark-brown subiculum 0.15 to 0.48 mm. thick, more often free, 

 ostiola not prominent. Asci cylindrical or slightly fusiform, 99.8 to 137.6 by 14. i 

 to 16.5JU. Paraphyses filiform, fugacious. Ascospores irregularly biseriate in the 

 ascus, fusoid or long elliptical, sometimes slightly curved; when mature, 5-septate, 

 may be slightly constricted at the septa, light brown, 28.3 to 33.8 by 7.6 to 9.05/4. 



Type locality. — Marble Mountain, St. Joe National Forest, Idaho. 



Habitat .^Living twigs and leaves of Picea engelmanni. 



Type material has been deposited in the Office of Investigations in Forest Path- 

 ology and in the Pathological Collections, Bureau of Plant Industry, Washington, 

 D. C. 



