STROMA AND FORMATION OF PERITHECIA 
IN HYPOXYLON 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 296 
PaTeyv Luro 
(WITH PLATE XVIII AND SEVEN FIGURES) 
Hypoxylon and its allies have been left more or less uninvesti- 
gated on account of the coriaceous structure of the stroma and the 
difficulty of cutting satisfactory thin sections. Dr Bary gave a 
general summary of Fuistinc’s researches on Hypoxylon and other 
members of the family, and said that it agreed with Xylaria poly- 
morpha in the structure of stroma and the development of asci. 
He also stated that there appeared in the young coil that is the 
primordium of the perithecium ‘“‘a row of broad cells irregularly 
rolled up and full of protoplasm,”’ called by Furstinc Woronin 
hyphae. As the perithecium grows, these disappear by gelatiniza- 
tion, and the ascogenous hyphae, the periphyses, and the para- 
physes grow out from a subhymenial layer of 6-8 cells that line the 
perithecium. The whole ascocarp, according to Dr Bary, is filled 
with a mass of paraphyses before the ascogenous hyphae appear 
at their base and grow up between them. 
In recent years only two of the family Xylariaceae have been 
studied, Poronia punctata by Dawson, and Xylaria by BROWN.’ 
In that part of his study related to the development of the perithe- 
cium, BRowN says that in the center of a tangle of hyphae smaller 
than the others there are broad cells shorter and richer in proto- 
plasm. These he identifies as Woronin hyphae, and states that they 
enlarge and probably divide, and then round off to form the large 
multinucleate ascogonia which usually fall to the bottom of the 
perithecium and there bud out the ascogenous hyphae. He further 
* Dawson, Marra, On the biology of Poronia punctata. Ann. Botany 14: 
245-260. Igo0. 
2 Brown, H. B., Studies in the development of Xylaria. Ann. Mycologict 
II: 1-13. 1913. 
Botanical Gazette, vol. 73] i 
