PYRENOMYCETES. 



127 



A. firm, pseado-parenchymatous mass of hyphoe is thus formed at 

 the base of the loosely-woven Sphacelia, which is in part trans- 

 formed into the hard sclerotium, and the remainder thrown off. 

 A dark, hard, poisonous body, longer than the natural grain, is 

 thus formed ; these bodies are known as Ergots, and were formerly 

 considered to be a distinct species, Sclerotium clavus (" Secale 

 cornutum," Ergot, Fig. 116 A, c). The THIRD STAGE, described 

 as Claviceps purpurea, is developed in the following spring from 

 the germinating sclerotium, which produces dark-red stromata 

 with short stalks. In the stroma numerous perithecia with asci 

 and ascospores are produced. The latter may infect young flowers 

 of the cereals, in which the disease is then developed as before. 



FIG. 117. Nectria cinnnlarina : a branch of Acer pseudoplatanus, with conidial-layers 

 and perithecia (nat. size) ; b a conidial -layer (Tubercularia vulgaris) ; c, a mass of peri- 

 thecia. (6 and c x 8.) 



Several species of the genus Nectria, with blood-red perithecia, are found as 

 dangerous parasites, especially N. ditissima, which causes " Canker " in the 

 Beech, Ash, and Apple, etc. ; N. cucurbitula, which appears on Pine-trees, and 

 N. ciimabarina (Fig. 117), whose conidial form was.formerly named Tubercularia 

 vulgaris. Folystiyma rubrum forms shining red spots on the green leaves of 

 Prunus-species.Epichloe typhina is parasitic on the sheaths of Grasses, on which 

 it first forms a white conidial-layer, later on a yellow layer of perithecia. Cor- 

 dyceps (Chrysalis Fungus, Figs. 118, 119) lives in and destroys insects, and after 

 compassing their death produces the club-formed, generally yellow, stromata, 

 one part of which bears conidia (Isaria) and another perithecia. C. militaris 

 (Fig, 118) on the chrysalides and caterpillars of moths, is the most common. 



W.B. K 



