STRUCTURE. 39 
yellow Uredine, of which it is a condition. Probably, in every 
species of the Pucciniei, it may hereafter be proved, as it is 
now suspected, that an unicellular Uredine 
precedes or is associated with it, forming 
a condition, or secondary form of fruit 
of that species. Many instances of that 
kind have already been traced by De Bary,* 
Tulasne, and others, and some have been a 
little too rashly surmised by their followers. 
In Phragmidium, the pedicel is much more 
elongated than in Xenodochus, and the spore 
is shorter, with fewer and a more definite 
number of cells for each species; Mr. Currey 
is of opinion that each cell of the spore in 
Phragmidium has an inner globose cell, ro, 20.—Xenodochus ear 
which he caused to escape by rupture of the ia 
outer cell wall as a spheroid nucleus,t leading to the inference 
that each cell has its own individual power of germination and 
reproduction. In Triphragmium, there are 
three cells for each spore, two being placed 
side by side, and one superimposed. In one 
species, however, Zriphragmium deglubens 
(North American), the cells are arranged as 
in Phragmidium, so that this represents really 
a tricellular Phragmidium, linking the pre- . 
sent with the latter genus. In Puccinia 
the number of species is by far the most 
numerous; in this genus the spores are uni- 
septate, and, as in all the Puccinigi, the 
peduncles are permanent. There is great 
variability in the compactness of the spores 
in the sori, or pulvinules. In some species, 
the sori are so pulverulent that the spores "99 2)7 Phragmidium 
are as readily dispersed as in the Uredines, 
in others they are so compact as to be separated from each 
* De Bary, ‘‘ Ueber die Brandpilze,” Berlin, 1853. 
+ Currey, in “‘ Quart. Journ. Mier. Sci.” (1857), vol. v. p. 119, pl. 8, fig. 13. 
