8 



base of the stroma of Cordyceps capitata and C. entomorrhiza. 

 Cordyceps, Robertsii, a' New Zealand species, parasitic on the 

 larva of Hepialus virescens, is one of the finest species belonging 

 to this genus. 



In the Order Perisporiacei the sporidia are set free by the 

 decay of the perithecia, the species not being furnished with a 

 mouth. Some of the plants belonging to the Order are beautiful 

 objects for the microscope, but very prejudicial to our crops. 

 Thus Sphaerotheca pannosa L6v. covers the leaves and shoots of 

 roses with a clothlike felt, thus preventing respiration, and causing 

 the destruction of leaves and flowers. Sphaerotheca Castagnii 

 Liv. is equally destructive of our hop crops. Phyllactinia guttata 

 Fr. is common on the leaves of various trees. Erysiphe Martii 

 Lk. attacks our late crops of peas, often destroying them utterly 

 in dry seasons. These plants are supported on the leaves by very 

 elegant supports, or fulcra. 



There remains only the Physomycetes and Mucorini to be 

 considered. The first Order is intermediate between Ascomycetes 

 and Hyphomycetes, agreeing with the former in the free formation 

 of its sporidia within a, generally globose, closed sac ; with the 

 latter in its free, fertile, threads which are never compacted into 

 an hymenium. The species belonging to these Orders, like the 

 greater part of moulds, grow on decaying substances, and 

 frequently on such as are used for food. In some instances, 

 perhaps, the germination of the sporidia induces decay, and 

 certainly accelerates it. Certain species of Mucor promote 

 fermentation in fluids, like the true moulds, as Penicillium. In 

 the genus Syzygites common on decaying Agarics in woods, the 

 fertile threads throw out little tubercles from their forked 

 branches — the tubercles soon touch each other and coalesce ; a 

 dissepiment is formed on either side, the two intermediate 

 membranes are absorbed, and, finally, the united cells swell and 

 form an irregular sac, which soon produces an abundance of 

 sporidia ; thus resembling the connecting tubes of Zygnema 



