HYPOCREALES 



253 



A representative of the third series of the Scolecosporeae is Cordyceps, 

 which includes about 200 species and has fructifications of such a varia- 

 tion of structure that it is difficult to define them exactly. Most of them 

 attack insects and only form perfect fructifications on substrates rich in 

 proteins, as cadavers of insects or Elaphomyces fructifications. The 

 biological relationships are not sufficiently clear; in any case they may be 

 saprophytic; thus in Norway, the mycelium of C. norvegica on pine 

 bombycid caterpillars is normally saprophytic in the forest floor and its 

 parasitism is only facultative (Sopp, 1911). 



Its imperfect forms belong to the Verticillium-Penicillium types and, 

 as far as they appear on infected insects, are called Muscardine, which 

 name is transferred to the disease itself. With sufficient nourishment, 

 the conidiophores coalesce into graceful white or bright-colored coremia 

 (Figs. 166, 167); they are classed in the Imperfect genus Isaria, e.g., the 

 coremia of C. militaris were called /. farinosa. 





taaOttLv.r. 



m-ms?m 



Fig. 168. — Cordyceps rhynchoticola. Habit, on dead leaf-louse. ( X 3; after Mailer, 1901.) 



The perithecial stromata of the simpler forms, as in the Brazilian 

 C. rhynchoticola found on dead leaf lice, are reminiscent of the higher 

 species of the Amerosporae. C. rhynchoticola surrounds the cadavers 

 with a loose hyphal felt, clings firmly to the substrate, and spreads out 

 on it somewhat as in Fig. 168. The necks of the solitary, flask-shaped 

 perithecia project over the stroma about 0.25 mm. 



In the higher forms, as in all the Hypocreales, there occurs the differ- 

 entiation of the stroma into fertile and sterile parts; the infected animal 

 is penetrated in all directions by hyphae, mummified, and changed into a 

 sclerotial structure from which later grow the perithecial stromata. In 

 C. norvegica, they form a narrow clavate structure up to 20 cm. long 

 on whose whole surface are imbedded the perithecia. It suggests 

 Clavaria pistillaris of the Basidiomycetes. In the neighboring collective 

 species, C. militaris, and in C. ophioglossoid.es on the fructifications of 

 Elaphomyces muricatus, these clubs are again differentiated in a sterile 

 base and fertile top (Fig. 169). In still others, especially in tropical 



