l62 MYCOLOGY 



parasitically on insects and their larva and some in subterranean fungi. 

 The mycehum kills the insect or larva and mummifies it. Out of the 

 host grow conidiophores (Isaria) in early stages of development, and 

 later stalked stroma, in which on enlarged terminal portions the per- 

 ithecia with asci and ascospores are found. C. militaris and C. cinerea 

 occur on insects, or insect larvae. C. sinensis is found on caterpillars 

 in eastern Asia, while C. ophioglossoides grows on the fruit bodies of 

 species of Elaphomyces (see ante, page 70) (Fig. 21). Claviceps is a 

 genus of fungous parasites found in the developing caryopses of various 

 grasses. Its conidial stage was formerly known as Sphacelia. Claviceps 

 purpurea and C. microcarpa are important species and their life his- 

 tories will be described in the third part of this book. As ergot, the 

 sclerotia of Claviceps purpurea are used in medicine (Figs. 56 arid 57). 

 Fifty-seven genera and three doubtful ones are recognized and described 

 in Engler's Die natiirlichen Pflanzenfamilien. 



Family 2. Dothideace^. — This family comprises twenty-four 

 genera among the most important of which is Plowrightia (Fig. 22) 

 and PkyllAchora. The fruit bodies of these fungi is spheric with definite 

 mouth and without distinct peridium, as they are found imbedded in a 

 black stroma. Plowrightia includes twenty species of fungi, which 

 form stroma in the interior of host plants, and which break through to 

 the surface, and form pimples in the center of which the opening to 

 the perithecium is found. The spores are egg-shaped, two-celled, 

 hyaline, or bright-greenish. Plowrightia ribesia is found on dried 

 twigs of species of currants Ribes in Europe and North America. 

 P. virguUorum occurs on brick in northern and middle Europe, P. 

 Mezerei grows on dead branches of Daphne in middle Europe and Italy. 

 P. insculpta is found on dried branches of Clematis vitalba in Bel- 

 gium, France, Germany and Italy and P. morbosa is the cause of black- 

 knot of the cherry and plum (Prunus) and will be described subsequently. 

 Phyllachora is a large genus of some 200 species found mostly on the 

 leaves of various plants; P. graminis is the commonest species of cos- 

 mopolitan distribution on grasses and sedges. The warty spot of clover 

 is Phyllachora trifolii. 



Famil-v 3. SoRDARiACE^.— The perithecia in this family are 

 superficial, or deeply sunken in the substratum and often break through 

 at maturity. The stroma is usually absent, but when it occurs the 

 perithecia are sunken with projecting papilliform beaks. Theperithecia 



