630 



Stroma erumpent-superficial, sul (globose, generally from J-f cm. 

 diam., deep brick-red when mature, often paler when young, solitary 

 or subconfluent. Perithecia peripherical in a single layer, small, sub- 

 globose, slightly prominent. Asci cylindrical, spore-bearing part 70- 

 80 x 6-7 p, paraphyses abundant, simple. Sporidia uniseriate, opake, 

 inequilaterally elliptical, 10-12x4-5//. 



Generally on bark of dead beech trees, but also on oak, willow, 

 birch, and some other trees. 



Common throughout the United States and Canada, as well as in 

 Europe. This and the next species are often accompanied by an 

 abnormal growth (Institute acariforme, Fr.) consisting of a spreading 

 fringe of somewhat flattened, ochraceous or rust-colored, more or less 

 branched processes surrounding the base of the stroma, and about 

 equal in length to its diameter, and bearing an abundance of very 

 minute, obovate, subhyaline conidia. Whether this should be con- 

 sidered the true conidial stage of the Hypoxylon is doubtful, as its 

 occurrence is exceptional. The case is in some respects analogous to 

 that of Sphceria flabelliformis, Schw. and the Xylaria from which it 

 springs, but with this difference: the affected Xylaria is always 

 abortive, while the Hypoxylon surrounded with its conidial fringe 

 matures its fruit. 



H. Howeianum, Pk. 24th Rep. N. Y. State Mus. p. 98. 



Stroma depressed-globose, 5-15 mm. across, light brick-red, nearly 

 smooth, but punctate from the minute, black ostiola, solitary or subcon- 

 fluent. Perithecia peripherical, monostichous, minute, ovate, \-\ mm. 

 high. Asci (spore-bearing part) 45-50x5 p, with a slender, thread- 

 like base, 35 p. long. Sporidia uniseriate, opake, subinequilaterally 

 elliptical, 6-7 x 3-3J p. 



On dead limbs of deciduous trees, New York (Peck), on Ostrya 

 Virginica, Iowa (Hoi way), on dead standing shrubs and fallen limbs 

 of oak, New Jersey (Ellis), on dead limbs, Pennsylvania (Everhart & 

 Rau), Ohio (Morgan), Nebraska (Miss L. S. Doud). 



The substance of the stroma is of a blue-black color, and a vertical 

 section shows a radiate-librous structure with one or two faint con- 

 centric zones. The interior of the stroma in H. coccinewm is homo- 

 geneous in structure, and of an even gray-black color. That species 

 is also distinguished from this, by its smaller stroma roughened by the 

 slightly projecting perithecia (J-J mm. diam.), and by its larger asci 

 and sporidia. In the Nebraska specimens the perithecia are distinctly 

 prominent, but in other respects they do not differ from the normal 

 form. 



H. commutatum, Nitschke, var. Holwayanum, S. & E., Mich. II r 

 p. 570; Sacc. SylL 5969. 



