24 BULLETIN 380^ U. S, DEPAETMENT OF AGRICULTURE. 



and put forth a very blunt apex. All are composed of a corky, 

 parenchymatous, very dense, soft yellow material. The mature 

 ones attain a diameter of 3 to 4 millimeters and a height of 1 to 2 

 millimeters, and on the somewhat reddish, and finally rusty red to 

 yellow top, they are marked by black points, the ostioles." The 

 Tulasnes observed that before the stromata reached their full size 

 the pycnidial cavities were formed within them, sometimes " widely 

 open," sometimes "narrow labyrinthine," and that through one or 

 many openings in the top of the pycnidia, the long, twisted, orange 

 tendrils, composed of mucus, and innumerable thin linear spores 

 were expelled. " Perithecia are developed chiefly in stromata des- 

 titute of spermogonia, or more often with only a few * * * they 

 arise very abundantly and irregularly, some barely buried in the 

 yellow corklike substance, others lower down and seemingly located 

 in the bark of the host itself." 



Although the Tulasnes included all their material under a single 

 species, they noted that the pycnidial stromata of the American 

 specimens (really Endothia gyrosa) differed considerablj^ from the 

 European {E. -flu-ens). In describing the former, they say (83, p. 

 88) "The American fungus is said to grow in the bark of Fagus' 

 and Juglans * * * as a whole it abounds with numerous, very 

 small spermatia. Allierefore if it is very thinly sectioned, the pieces, 

 examined with a compound microscope, show cavities just as if you 

 had before your eyes the smallest Gautieria or Balsamia." The 

 Tulasnes do not try to distinguish definitely between stroma and 

 mycelium, but merely state that the stromata develop within the 

 mycelium. 



Euhland (67), who was the next writer to discuss the morphology 

 of a species of Endothia, defines the various portions of the fungus 

 body in detail. According to his definition (p. 16) a "stroma (in 

 distinction from mycelium) is the sum total of that part of the 

 vegetative portion of the fungTis body, which, without serving ex- 

 clusively for absorption, takes part in the formation of the fruit 

 body." He sets aside Fuisting's (36, p. 185) division of the fungus 

 body into an epistroma and a hypostroma, as essentially^ nothing but 

 the distinction of " conidial layers " and " perithecial stroma-" 



Euhland divides the fungus body into an ectostroma and an ento- 

 stroma. The ectostroma gi^ows " on the upper surface of the paren- 

 chyma of the bark, between it and the periderm, and is composed of 

 a generally wide-lumened plectenchyma which does not possess the 

 power of absorption." This portion has the following functions: 

 " The formation of the conidia, the opening and breaking off of the 

 periderm, and the stimulation of the development of the entostroma." 

 The entostroma, on the other hand, according to Euhland, " lives in 

 the parenchyma of the bark, and while young is in a high degree 



