28 



BOTANY AND PHARMACOGNOSY. 



surrounded by a dark layer, and this, if developed upon rye, con- 

 stitutes the ergot grains (Fig. 19, B) used in medicine, these 

 grains being a number of times larger than the rye grains which 



Fig. 19. Claviceps purpurea. A, mycelium developing conidia; B, an ear of rye 

 with a number of ripe sclerotia replacing grains of rye, and known as ergot; C, sclerotium 

 developing spherical fruit bodies: D, fruit body in longitudinal section showing numerous 

 flask-shaped perithecia at the periphery; E, enlarged perithecium with numerous cylin- 

 drical asci; F, closed ascus with 8 asccspores; G, discharge of ascospores; H, single thread- 

 like ascospore. — ^A, after Brefeld; B, after Schenck; C-H, after Tulasne. 



they replace. The mycelial tissues connected with the host plant 

 die, and the ergot drops to the ground. At this stage the ergot 



