PRINCIPAL GROUPS OF PLANTS. 



53 



containing numerous cylindrical asci (Fig. 29, ), each of which 

 contains eight spores (Fig. 29, F) ; the latter are i -celled, hya- 

 line, and thread-like (Fig. 29, H). These spores are carried by 



FIG. 29. Claviceps purpurea. A, mycelium developing conidia; B, an ear of rye 

 with a number of zipe 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 ascospores; G, discharge of ascospores; H, single thread- 

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



the wind to the flowers of certain of the grasses, as already stated, 

 and the life history or cycle of growth begins again. 



