RESEARCHES ON THE MUCORINI. 73 



Jonesii, which cannot therefore be normally parasitic on 

 Mucor. Inasmuch also as it reproduces itself for an indefi- 

 nite number of generations, it can have no genetic bond 

 either with Mucor Mucedo, or any other of the Mucorini. 



The aerial sporangiferous hyphae of Cli(Btocladium, like 

 those of Circmella and Rhizopus, have an indefinite growth 

 after the fashion of a liane.^ But it is not rare to find one of 

 the vegetative hyphse put out laterally a short and thick 

 brancli, which frequently divides repeatedly dichotomously, 

 and forms a white tubercle tangent to the hypha or even 

 enveloping it entirely. These tubercles or mycelial masses 

 are altogether similar to those which proceed from the germi- 

 nation of the spores. Some of their branches may be pro- 

 longed into the air as new, fructiferous, indefinite hyphae. 

 They are, perhaps, homologous with the tufts of radicles 

 which develope on the aerial indefinite hyphae of Rhizopus^ 

 and are the point of origin of new fructifications. 



Sometimes it happens that the mycelial mass resulting 

 from germination is very much reduced ; the spore puts out 

 five or six palmate tubes, one of which immediately raises 

 itself in the air and becomes covered with fructification, while 

 the others are like the fingers of a glove, and terminate at a 

 short distance from the spoi-e. In this case the submerged 

 mycelium is a mere base of support for the aerial hypha, pro- 

 ducing fructification. 



Besides sowing the pure spores of Chcetocladium Jonesii, 

 we sowed them mixed with those of Mucor Mucedo. The 

 mycelia of the two species so different in their characters, 

 the one condensed into masses, the other difi'use, vegetated 

 as if they were independent, and without forming any 

 attachment the one to the other. The first put out its more 

 slender branching sporangiferous hyphae, the other its simple 

 ones, but wherever a hypha of Chaetocladium came in contact 

 in the air with one of Mucor, an intimate adhesion took 

 place, and at the point of contact the filament of Chcetocladium 

 put out large branching processes, which, becoming felted 

 together, formed round the two hyph« a large white tubercle, 

 from which new fruit-bearing filaments of Chatocladium 

 originated. If the hypha of Mucor is very young and still 

 in process of elongation when thus attacked, it ceases to 

 develope, but if its protoplasm has already accumulated in 

 its terminal dilatation it produces a sporangium, and forms 

 and ripens its spores. 



' Sometimes degraded forms which are more or less definite in their 

 growth are produced in liquids, such as horse-dung decoction, which are 

 iusufBciently nutritive (fig. 37, a— I). 



