Cunningham. — The Genus Cordyceps in New Zealand. 373 



rapidly carried in the blood-stream to different parts of the body, where 

 they in turn give rise to hyphae. In this manner the fungus rapidly spreads 

 and quickly kills the host. 



Infection of the host may occur from the germ-tube from an ascospore, or 

 from hyphae developed from conidia borne by the Isarial form of Cordyceps. 

 A conidium may germinate, and the subsequent hyphae live saprophytic- 

 ally on decaying wood or other organic matter for some considerable 

 time. These hyphae on coming in contact with a host are eapable of 

 entering the host-tissues. In the decaying wood from which Cordyceps 

 Aemonae Lloyd was taken, mycelial development was so pronounced as to 

 be visible to the naked eye. The writer carried out some rough experi- 

 ments to ascertain whether this mycelium was capable of attacking the 

 larvae of Aernona hirta Fabr., the host of G. Aemonae. Healthy host larvae 

 (quiescent) were obtained from rotting logs in which no sign of Cordyceps 

 was found, and were buried in pots filled with sterilized sawdust in which 

 were mixed fragments of infected wood taken from the centre of the los 

 that contained G. Aemonae. The pots were kept moist and covered with 

 bell jars. In two months' time these larvae were exhumed, and were all 

 found to be dead and surrounded by hyphae. They were replaced, and 

 in three months stromata bearing the Isarial stage of C. Aemonae appeared 

 above the surface of the sawdust. Unfortunately this experiment was 

 not carried further to determine whether the perithecial stage could be 

 obtained ; but at the time of the first experiment Isarial forms of C. Aemonae 

 were brought into the laboratory from logs in the forest in which they were 

 found, and were buried in sawdust with the stromata alone showing. The 

 pots were kept moist and covered ; in three months immature perithecia 

 had appeared on one or two of the stromata. (Plate LIX, fig. 1, b). 

 The sawdust used in these experiments was obtained by sawing uo dead, 

 sound, dry logs of niahoe (Melicyi.us ramiflorus Forst.). 



In the host the hyphae continue to develop until finally the whole of 

 the internal tissues are replaced by the mycelium of the fungus, when it 

 forms a hard, compact mass, the cuticle and sometimes portions of the 

 alimentary system alone remaining unaltered. (Plate LXI, fig. 2.) This 

 mycelial mass is known as a sclerotium ; from it, usually after a period 

 of rest, the stromata bearing the fructifications of the fungus arise. The 

 stromata vary considerably in shape, size, and number, according to the 

 nature and habitat of the host. ]f the host is subterranean, then the 

 stromata will necessarily have to be long enough to rise to the surface of 

 the ground, so the length would be governed by the depth of the host. 

 Again, if the host is exposed, as in the case of Cordyceps clacvlata (Schw.) 

 Ellis & Ev.,* the stromata would necessarily be short. 



In some species there are two kinds of fructification : the first is known 

 as the Isarial form, and bears conidia ; the second furm, which appears after 

 the Isarial (when the latter is present), bears the ascospores. Conidia are 

 simple, short-lived spores, and are abjointed in immense numbers from 

 the ends of hyphae. They may be borne on a stroma, in which case they are 

 abjointed from the terminals of the hyphae forming the stroma, or may 

 occur on the terminals of hyphae which form a loose covering over the 

 external surface of the host. The relationship between this Isarial and 

 the later (or Cordyceps) stage is known in a few species only, and in the 

 majority of cases is assumed merely on account of the occurrence of both 

 forms from the same host. As mentioned above, Isaria is capable of 



* This species occurs on various species of Lecanium. 



