298 



stroma ) 15. H. cohaerens. 



c. Stroma flattened above, turbiuately narrowed below, bear- 

 ing numerous (usually over 25). not very prominent peri- 

 thecia 16. H. turhiiiuhitum. 



Descriptions. 

 The following de.^criptions are adapted mainly from "North American 

 I'yrenomycetes" by Ellis and Everhart. 



Hypoxvlon, BulUard. 

 Stroma of carbonaccuis or woody-corl^y consistance, dark-lirown or 

 l)lack within, e.\ternally ranging from almost white through shades of 

 red, brown or purple, to black, free from the first or erumpent-superficial, 

 sometimes more or loss sunk in the wood, globose, subgloboso, or more or 

 less effused and crustaceous, at first covered by a conidial growth, finally 

 bare. I'erithecia 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 papilliform or umbilicate osti- 

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

 inequilateral or curved, continuons, brown. 



7. JI. Petersii, B. & C. 



Stroma large, 2.rt-ii cm. long. 2.~>-4 cm. wide, .Tn-l.") cm. thick, ranging 

 iii shape fmrn .ilniust circular to oblong or elliptical, convex above, some- 

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

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

 tached with a s])rca(ling margin free at the sides. In the elliptical forms 

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

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

 thick, leathery, membranaceous veil which soon disai)i)ears except around 

 the margin where there persists a leather-colored strip of irregular width 

 which becomes narrower and darker-colored with age. Substance corky, 

 slightly fibrous, brown, ujiijer spore-bearing part blackish-brown, slightly 

 carbonaceous. I'erithecia subglobose or sub-elongated, .o-.7o mm. long, 

 with necks ending in i)a]iilliform ostiola. arranged in several layers, which 

 in places are so crowded tlnit the layers are not distinct. The entire 

 spore-bearing stratum averages about H mm. in thickness. Asci cylin- 



