CARPOSPOREM. 



3'^7 



mycelium, which attaches itself to the surface of the ovary of Grasses, especially of Rye, 

 while still enclosed between the paleae, covers it with a thick weft, and partially pene- 

 trates into its tissue, while the apex and often other parts of the ovary remain exempt 

 from its attacks. The ovary becomes replaced by a soft white mycelial tissue which 

 retains nearly its original form, the style being not unfrequently still borne on its summit. 

 The surface of the tissue of the Fungus is marked by a number of deep furrows and 

 forms a large number of conidia on basidia arranged radially, imbedded in a mucilaginous 

 substance which exudes between the paleae. In this condition the Fungus had been at 

 one time considered a distinct genus, and described under the name of Sphacelia. The 

 conidia can germinate at once and immediately again detach conidia, which, according to 

 Kiihn, again produce a sphacelia in other Grasses. The mycelium of the sphacelia 

 forms, when the production of conidia has reached its height, a thick felt of firmer hyphge 

 at the base of the ovary, which is at first still surrounded by the looser tissue of the 

 sphacelia. This is the commencement of the sclerotium or Ergot; its surface soon assumes 



Fig. "Kfj.—Claviceps purpurea. A a sclerotium forming stromata c/ (Ergot) ; B longitudinal section of upper part of a 

 stroma, cp the perithecia ; C a perithecium with the surrounding tissue (greatly magnified) ; cp its orifice, hy hyphse of 

 the pileus, sh epidermal layer of the pileus ; D an ascus ruptured and allowing the spores to escape (after Tulasne). 



a dark-violet colour, and grows to a horn-shaped body, often as much as an inch in 

 length. In the meantime the sphacelia ceases to grow, its tissue dies and is ruptured 

 beneath by the sclerotium, and carried upwards on its summit, where it is placed like a 

 cap and afterwards falls off. The hard ripe sclerotium now remains till the autumn, or 

 usually till the next spring in a dormant state; the formation of the stroma begins when 

 the sclerotium is lying on the damp ground. The stromata arise beneath the skin, a 

 number of closely-packed branches being formed at definite points from the medullary 

 hyphae; the bundle breaks through the skin, and grows up into the stroma which consists 

 of a long stalk and a globular head. In the latter a large number of flask-shaped perithecia 

 (Fig. 209, JB and C, cp) appear, which do not possess a clearly-defined wall. Each 

 perithecium is filled from the bottom by a number of asci, in each of which several 

 slender filiform spores are produced. These spores swell up in damp situations, and 

 put out germinating filaments at several points. When they reach the young flowers of 



