MiCROSPHAERA 135 



corylca on Alnus were under observation. M. Casimir de Candolle 

 has kindly sent me the example of '*Schleich. cent, exsicc. n. 

 (:>% " from De Candolle's herbarium, and the fungus proves to be 

 Phyllactinia corylca. 



Wall 



Mia 



pcnii 

 Micr 



Fortunately, therefore, we can still, by adopting Wallroth's varietal 

 name, retain the specific name abii for the present species. 



Returning to the study of the various forms of M. alni (Wallr.) 

 we find that in American examples the perlthecia, which are some- 

 times {e, g., in certain specimens on Cotyliis Americana) only 66 ft 

 in diameter may reach to as much as 130/i in diameter on other 

 hosts. In American material, further, the appendages gradually 

 become longer, reaching in rare cases a length of 2^ times the 

 diameter of the perithecium. Also, the branching of the apex of 

 the appendages tends gradually to become more elaborate, reach- 

 ing its height in the forms on Cormis and Qncrcus which have 

 been described as J/ pulchra, j\L dcnsissima, and M. qncrcina. 



M, pidchra has already been united by American mycologists 

 to M. alni, and there can be no doubt of the correctness of this 



arrangement. 



alternifc 



of the most striking of the American forms, and in its extreme state, 

 with the perithecia 130 a in diameter, with 17-22 appendages 1 1^ 

 to twice the diameter, and especially the very ornate apical branch- 

 ing, producing a more or less square outline (Figs. 4-6) seems at 

 first almost worthy of separation. There is, however, no diffi- 

 culty with sufficient material at hand, in seeing that ''M, pidchra '' 

 is too intimately connected with many American forms of Jf alni, 

 I have seen specimens on Alnus incana from New York with peri- 

 thecia averaging 120 //in diameter, with 20-26 appendages, not 

 much exceeding the diameter of the perithecium, but with the 

 apical branching very similar to that of ''M. pidchrar Moreover, 

 the large sized perithecia and numerous appendages are not invari- 

 ably found in ^'M. pulchra'' itself; in the type specimen there 

 occur side by side with perithecia 1 30 p. in diameter, with 16-20 

 appendages, smaller ones (containing ripe asci) 90 p- in diameter, 

 with only 6 appendages. 



