DEVELOPMENT OF PLANTS 



229 



90. Forms with Broadly Opened Ascocarps. — The remaining 

 orders of the Ascomycetes include genera in which the ascocarps 

 are broadly open and often associated with large masses of the 

 mycelium, thus forming conspicuous bodies. 



Fig. 153. Fig. 154. 



Fig. 153. Head of rye infested by the parasite, Claviceps, which has 

 transformed several of the grains into black masses of mycehum known as 

 sclerotia. 



Fig. 154. Various phases in the life history of Claviceps: A, a young 

 grain or pistil infested with the parasite. B, enlarged view of the mycelium 

 as it appears on the surface of the pistil, showing the formation of numerous 

 spores. C, the hyphae of a sclerotium growing out and forming several 

 purplish stalks, each capped with knob-like clusters of ascocarps. D, en- 

 larged sectional view of one of these knobs, showing numerous ascocarps 

 on the periphery. E, one of the ascocarps enlarged, as, asci. F, an ascus 

 containing eight thread-like ascospores. 



