OBSERVATIONS ON HERPOTRICHIA NIGRA 
AND ASSOCIATED SPECIES 
Fred J. Seaver 
Several years ago while attempting to work out the identity of 
Herpotrichia nigra Hartig and Neopeckia Coulteri (Peck) Sacc., 
the writer was surprised to find the ascospores of a third species 
on Picea which was at first thought to be an undescribed species of 
Herpotrichia. The spores of this species were fusiform, long and 
narrower than those of Herpotrichia nigra and, while usually 
5-septate, were often 6-septate and occasionally even 7-septate, 
while those of Herpotrichia nigra were broad, blunt and never 
more than 3-septate so far as observed. 
This strange species was first detected while studying Ellis & 
Everhart’s Fungi Columbiani i/ 3 /, a specimen of Herpotrichia 
nigra which was erroneously distributed under the name of Lasio- 
sphacria Coulteri. The spores of this species were again observed 
while examining a specimen of Herpotrichia nigra on Picea Engel- 
manni sent from Colorado by Bethel, July 7, 1914. 
After a careful study it was found that these fusiform spores 
were not the spores of a Herpotrichia as at first suspected but 
were those of a Mytilidion which has .been repeatedly found on 
conifers associated with Herpotrichia nigra. The genus Mytilid- 
ion belongs to the Hysteriales and the perithecia of the plants of 
this genus are laterally compressed and closely resemble a minia- 
ture clam or other bivalve, opening by a slit across the top of the 
perithecium and very different from the subglobose perithecia of 
Herpotrichia. The perithecia of the Mytilidion are, however, so 
intimately associated with those of the Herpotrichia that their real 
characters may be easily overlooked and when removed together, 
the spores of the Mytilidion may be mistaken for the mature spores 
of the Herpotrichia. If, however, the perithecia are removed and 
studied individually, it will be found that the fusiform spores are 
always obtained from the hysteriform perithecia while the sub- 
globose perithecia contain the 3-septate spores which are character- 
istic of Herpotrichia nigra. 
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