298 



stroma ) 15. H. cohaerens. 



c. Stroma tlaticiuMl above, turhinatoly narrowed below, bear- 

 ing nnnierous (usually over 25), not very prominent peri- 

 tliecia 111. II . tinhhnilitlion. 



Descriptions. 

 The following ilesoription.s are adapted mainly from "North American 

 I'yreuomycetes" by Ellis and Everhart. 



Hypoxylon, Bulliard. 



Stroma of carbonaceous or woody-corky consistance, dark-l»rown m- 

 black within, externally ranging from almost white thrcnigh shades of 

 red, brown or purple, to black, free from the first or erumpent-sui)erticial, 

 sometimes more or less sunk in the W(wd, globose, subglobose, or more or 

 less effused and crustaceous, at first covered by a conidlal growth, tinally 

 bare. Perithecia peripherical in a single layer or sometimes in several 

 layers concentrically or irregularly arranged, globose, ovate or oblong, 

 coriaceous or corneo-coriaceous, sunk in a stroma, but generally with the 

 upper part more or less projecting, with a ])apilliform or umbilicate osti- 

 ohun. Asci cylindrical, S-spored. Spores uniseriate, elliptical or fusoid, 

 inequilateral or curved, continuous, brown. 

 J. H. Petersii, B. & C. 



Stroma large, 2.n-(i cm. long, 2.5-4 cm. wide, .75-1.5 cm. thick, ranging 

 ill shape fi'om almnst circnljir (o oblong or elliptical, convex above, some- 

 times even, often raised into a few large folds or ridges wliicii usually 

 extend cro.sswise but occasionally lengthwise of the stroma, centrally at- 

 tached with a spreading margin free at the sides. In the elliptical forms 

 the attachment extends lengthwise almost from end to end. The surface 

 sometimes exiiilats deep cracks. The stroma is covered at first with a 

 thick, leathery, membranaceous veil which soon disa])]»ears except around 

 tl;e margin where tliei'e pei'sists a le.i(liei--colored strip of irregulai' width 

 which l)ecomes narrower and darker-colored with age. Substance corky, 

 slightly fibrous, brown, upper sjioi-e-bearing part blackisli-brown, slightly 

 ("irlionnccons. I'crillieciji subglobose or sub-elongated. .5-. 75 nun. long, 

 with necks (hiding in paiiillifoian ostiola. arranged in several layers, which 

 in places are so cr(i\v(l<'(l thai the layers are not distinct. The entire 

 spoi"e-be:iring stratum averages about 5 nnn. in thickness. Ast-i cylin- 



