TO PUCCINIA GRAMINIS, PERB. 
35 
form, colour and spore structure between Puccinia and Uredo than 
is the case with ALcidium and Uredo. The free spores of many 
species of Adcidium cannot be distinguished from the spores of 
many Uredines. ALcidium as a genus differs from Uredo princi- 
pally in the possession of spermogonia, of a peridium, but more par- 
ticularly in producing its spores in chaplets. All ALcidia , how- 
ever, do not possess spermatia, for of the thirty-two species enu- 
merated as British in the “ Handbook,” the presence of spermo- 
gonia is only noted in four ; while certain Uredines are provided 
with them, e.g., U. suaveolens , Pers., U. orchidis , Mart., U. gyrosa , 
Bebent, U. mer curialis, Link., U. Euonymi , Mart., and U. 
pinguis, D.C.* 
Sir John Lubbock, in his address to the British Association at 
York, last August, has very pertinently said, “ Naturalists are now 
generally agreed that embryological characters are of high value 
in classification,” the truth of which assertion is daily becoming 
more and more accepted by students of Natural History. 
Now when we cause the spores of ALcidia to germinate under 
circumstances in which we can watch the process, we find they do 
so inexactly the same manner as Uredo spores, namely, by the pro- 
trusion of a hyaline tube through the epispore. This hyaline tube 
gradually elongates, and into it are emptied the contents of the 
spore, which are passed onwards until they eventually reach the 
end of the tube. This tube (or tubes, for there may be more than 
one) undergoes in both instances the same spiral movements, and, 
unlike the tube produced by the germinating Puccinia spore, it 
does not, as a rule, produce secondary spores. 
The association of Aicidium with Uredo (in some state or other, 
either as Uredo , Puccinia, Uromyces , or Coleosporium ) upon the 
same plant, often upon the same individual, and even upon the 
same leaf, is a fact well known to practical mycologists. 
Of the thirty-two species of AZcidium enumerated in “ Cooke’s 
Handbook of British Fungi,” this association exists in twenty 
species. In some cases we find in nature this exists very closely, 
e.g., ALc. ranunculacearum, D.C., and Uromyces ficariae , Lev., ALc. 
epilobii, D.C., and Puc. epilobii, D.C. Aie. compositarum, Mart., 
and Puc. compositarum , Sch., are often found upon the same leaf ; 
while Puc. sparsa, Cooke, is expressly said by Dr. Cooke to be 
“only found amongst or near the exolete pustules of ALcidium 
Tragopogonis, Pers.f 
There is, however, a much wider question broached when we 
come to associate the JEcidium , known only to exist upon an 
exogenous plant with a Puccinia confined to endogenous plants. 
In order to convince reasonable minds, the evidence must be unim- 
peachable and complete. No mere coincidences, however 
* Tulasne — u Second Memoire sur les Medinees et les Ustilaginees. 1 
Ann. des Sciences Nat.,” 4 series, vol. ii., p. 116. 
t Cooke — “ Handbook of British Fungi,” p. 498. 
