16 British Uredinee and Ustilaginee. 
wort ina Pasteur’s flask, with Uredine yeast-spores, were 
with me unsuccessful. The spermatia do not germinate in 
pure water, but only in the presence of sugar. There is, 
however, often enough saccharine matter in the investing 
jelly of the exuded globule for a few of them to bud, 
as Mr. Lister’s figure shows, and as I have several times 
observed. 
Rebentisch * noticed the small black points which the 
spermogonia present in the spots upon pear leaves, on 
which Restelia cancellata are produced. Ungerft figures 
these structures, and describes them as a distinct species 
under the name Zcidiolum exanthematicum ; he regarded 
them as a peculiar exanthem of the affected plant. Meyent{ 
thought they played the part of the male element in the _ 
reproduction of the Uredinez, with which they were asso- 
ciated. Tulasne§ considered they were spore-forms 
developed from the same mycelium as their accompanying 
spore-forms, but, like De Bary, was unable to observe their 
germination. 
The spermatia of the Uredinee occur with all the 
spore-forms. They almost invariably precede and accom- 
pany the zcidiospores, being produced from the same 
mycelium, but generally occupying the upper surface 
of the leaf, while the ecidial cups occur on the lower. 
The first formed spermogonia are produced in the centre. 
of a spot; the next more externally, and so on centri- 
fugally. In many cases, however, they occur on the same 
surface and between the ecidia. When the acidiospores 
are cauline, the accompanying spermogonia are often 
* Rebentisch, ‘‘ Prodrom. florze Neomarch.” 
me Unger, ‘‘Die Exantheme der Pflanzen,” t. iii, figs. 18, 19. Wien; 
t Meyen, ‘‘ Pflanzenpathologie” (1841), pp. 143-147. 
§ Tulasne, Comptes rendus, tome xxxii, p. 472; and tome xxxvi, Pp. 1093. 
