152 FUNGI. 



which at first take a lenticular form, and group themselves before 

 the mouth of the parent cell in a globose mass (c.) Very soon, 

 however, they begin to move, and then vibratile cilia show them- 

 selves (d), and by means of these appendages the entire globule 

 moves in an oscillating manner as one by one the zoospores 

 disengage themselves, each becoming isolated and swimming 

 freely in the surrounding fluid. The movement is precisely 

 that of the zoospores of Algse. 



The generation of the zoospores commences within from an 

 hour and a half to three hours after the sowing of the conidia on 

 water. From the oogonia, or resting spores, similar zoospores, 

 but in greater number, are generated in the same manner, and 

 their conduct after becoming free is identical. Their movements 

 in the water usually last from two to > three 

 hours, then they abate, the cilia disappear, 

 and the spore becomes immovable, takes a 

 globose form, and covers itself with a 

 membrane of cellulose. Afterwards the 

 spore emits, from any point whatever of its 

 surface, a thin, straight or flexuous tube, 

 which attains a length of from two to ten 

 times the diameter of the spore. The ex- 

 tremity becomes clavate or swollen, after 

 FIG. 92^Sting spore * ne manner of a vesicle, which receives by 

 of cystopus candidus with degrees the whole of the protoplasm, 

 zoospores escaped. -^ Bar y ^ ea pr()cee( j s to describe experi- 



ments which he had performed by watering growing plants 

 with these zoospores, the result being that the germinating 

 tubes did not penetrate the epidermis, but entered by the 

 stomates, and there put forth an abundant mycelium which 

 traversed the intercellular passages. Altogether the germina- 

 tion of these conidia or zoospores offers so many differences 

 from the ordinary germination of the Uredines, and is so like 

 that which prevails in Peronospora, in addition to the fact of 

 both genera producing winter spores or oogonia, that we cannot 

 feel surprised that the learned mycologist who made these 

 observations should claim for Cystopus an affinity with Perono* 



