DlE-r.ACK OF APPLE TRKES. 



549 



ning of pvcnidia formation in a stroma shews as a dense mass 

 of hyphal tissue (PI. 21, b), in which later the individual pycnidi'a 

 arise (PI. 24, a). Each pycnidium has its own fairly thick wall 

 ( IM. 22a), and contains the spores which are borne on basidia. 

 The basidia are hyaline, biseptate, tapering at the end, and vary 

 greatly in length. The measurements most frequently are 8.24 — 

 I2.32/Z X I.I3IM- 



The spores (PI. 22, a) are hyaline, straight to curved, boat- 

 shaped or allantoid, and with acute or somewhat rounded ends. 

 They measure 4.62 — 6.i6/a X i-i55,"- 



Fig. t. 



The walls separating adjoining pycnidia become confluent, 

 so that the individual pycnidia become united and open through 

 a common stoma (PI. 24. a). 



In the stoma peculiarly swollen fungous cells (PI. 22 b) 

 have been observed. These cells are extraordinarily rich in proto- 

 plasmic contents, and are multinucleate. The nuclei showed up 

 well with the stain used — Diamant Fuchsin and liglit green. 



