38 



FUNGI. 



as species of Lecyihea. In Gystopns, the spores are sub-globose, 

 or somewhat angular, generated in a moniliform manner, and 

 afterwards separating at the joints. The upper spore is always 

 the oldest, continuous production of spores going on for some 

 time at the base of the chain. Under favourable 

 conditions of moisture, each of these spores, or 

 conidia, as De Bary terms them, is capable of 

 producing within itself a number of zoospores; * 

 these ultimately burst the vesicle, move about by 

 the aid of vibratile cilia, and at last settle down 

 to germinate. Besides these, other reproductive 

 "bodies are generated upon the mycelium, within 

 the tissues of the plant, in the form of globose 

 oogonia, or resting spores, which, when mature, 

 also enclose great numbers of zoospores. Similar 

 oogonia are produced amongst the Mucedines in 

 the genus Peronospora, to which De Bary con- 

 siders Cystopus to be closely allied. At all events, 

 Fro. 19.— ciistopus this is a peculiarity of structure and development 

 camhdus. ^^ ag ^ m ^ ^-^ j Q &u ^ other of the Gwomacei. 



In Uromyces is the nearest approach to the Pucciniasi ; in fact, 

 it is Puecinia reduced to a single cell. The form, of spore is 

 usually more angular and irregular than in Trichobasis, and the 

 pedicel is permanent. It. may be remarked here, that of the 

 foregoing genera, many of the species are not autonomous that 

 have hitherto been included amongst them. This is especially 

 true of Lecythea, Trichobasis, and, as it now appears, of 

 Uromyces.^ 



PuCctnlei. — This group diifers from the foregoing chiefly in 

 having septate spores. The pustules, or sori, break through 

 the cuticle in a similar manner, and here also no true peridium 

 is present. In Xenodochus, the highest development of joints 

 is reached, each spore being composed of an indefinite number, 

 from ten' to twenty cells. With it is associated an unicellular 



* De Bary, "Champignons Parasites," in " Ann. des Sci. Nat." 4 me ser. vol. xx. 

 t Tulasne, "Me'raoiresurleaUredin^es, &e.," in" Ann. des Sci. Nat." (1854), 

 vol. ii. p. 78. 



