ENDOTHIA PARASITICA AND RELATED SPECIES. 25 



capable of absorption, a power which it retains relatively perma- 

 nently." In addition to its absorptive function the entostroma forms 

 the pseudoparenchymatic cover for the perithecial walls. 



Ruhland studied herbarium material from the Royal Botanic Mu- 

 seum of Berlin and specimens from Saccardo and Cesati, and de- 

 scribed it under the name of Endothia radicalls (Schw.) Fr. (E. 

 fluens of the present writers). He distinguishes an ectostroma, 

 shaped like a truncated cone, consisting of fine, thin-walled hyphae, 

 so closely interwoven that the whole structure has a comparatively 

 firm quality. Among these hyphse are crystals of calcium oxalate. 

 As soon as this ectostroma breaks through the bark there is formed 

 near the middle a short-lived 1-chambered pycnidium. Below this 

 ectostroma (height 0.5 to 0.6 mm., diameter 0.7 to 1 mm.) the ento- 

 stroma grows out as a mycelium through the upper portion of the 

 bark. Ruhland says, " The entostroma with us does not produce per- 

 ithecia, but remains wholly mycelial." He studied the perithecial 

 stage in Cesati's specimens, however, and concludes that the peri- 

 thecia originate without much change in the size of the entostroma 

 and at a considerable distance, about 1 mm., below the ectostroma. 

 The long necks then penetrate through the overlying entostroma 

 and into the ectostroma to the base of the now functionless pycnidia. 

 The upper portion of the ectostroma is then quickly killed and 

 thrown off. 



Pantanelli briefly described the stromata of the genus Endothia, 

 and pointed out several morphological characters which he considers 

 distinctive of E. parasitica in contrast to E. fluens. Aside from spore 

 characters, which will be discussed later, Pantanelli (60, p. 870) con- 

 siders that E. parasitica is characterized by numerous stromata, at 

 first embedded in the bark, finally free ; by pycnidial cavities numer- 

 ous and irregularly arranged in various planes in the stromata deep 

 in the bark; pycnidial stromata 1.1 to 1.2 mm. in height and 2.1 to 2.2 

 mm. in diameter; ascogenous stromata, height 1.8 to 2 mm., length 

 2.5 to 3.1 ; width, 3 to 3.2 mm. ; perithecia arranged in two or three 

 layers; necks of perithecia averaging 1.25 mm., with inconspicuous 

 ostioles ; walls of the perithecia uncolored or light brown. 



Endothia fluens, on the other hand, has isolated stromata, chiefly 

 outside the bark ; pycnidia aggregated, regularly arranged in a single 

 superficial series; pycnidial stromata, height 0.1 to 0.5 mm., diameter 

 1.1 to 1.3 mm.; ascogenous stromata, height 1.1 to 1.4 mm., length 

 2.5 to 3.2 mm., width 1.2 mm.; perithecia arranged in a single row; 

 necks of perithecia averaging 0.15 mm.; ostioles prominent; walls 

 of the perithecia black. 



Anderson (1, pp. 17-21) described the development of the fructifi- 

 cations of Endothia parasitica in detail. He studied the growth of 



