112 
no one now doubts the connection of the majority of Uredines with Puccini, and 
it must be borne in mind that a much greater difference existed in form, colour, 
and spore structure, between Puccinia and Uredo, than is the case with Zeidiwm 
and Uredo. The free spores of many species of 42eidiwm cannot be distinguished 
from the spores of many Uredines. -dcidiwm, as a genus, differs from Uredo 
principally in the possession of spermogonia, of a peridium, but more particularly 
in producing its spores in chaplets. All cidia, however, do not possess sper- 
matia, for of the thirty-two species enumerated as British in the ‘‘ Handbook,” 
the presence of spermogonia is only noted in four; while certain Uredines are 
provided with them, e.g., U. suaveolens, Pers., U. orchidis, Mart., U. gyrosa, 
Rebent, U. mereurialis, 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 M4#eidia to germinate under circumstances 
in which we can watch the process, we find they do so in exactly the same manner 
as Uryedo spores, namely, by the protrusion 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 Aeidiwm with Uredo (in some state or other, either as Uvedo, 
Puccinia, Uromyces, or Coleosporiwm) wpon the same plant, often upon the same in- 
dividual, and even upon the same leaf, is a fact well known to practical mycologists. 
Of the thirty-two species of dfeidiwm 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, ¢.g., dc. ranunculacearum, D.C., and Uromyces 
ficarie, Lev., dc. epilobii, D.C., and Puc. epilobii, D.C. dic. compositarum, 
Mart., and Puc. compositarum, Sch., are often found upon the same leaf; while 
Puce. sparsa, Cooke, is expressly said by Dr. Cooke to be ‘‘ only found amongst or 
near the exolete pustules of Meidium Tragopogonis, Pers.+ 
There is, however, a much wider question broached when we come to associate 
the eidium, known only to exist upon an exogenous plant with a Puccinia con- 
fined to endogenous plants. In order to convince reasonable minds, the evidence 
must be unimpeachable and complete. No mere coincidences, however numerous, 
can per se be taken as conclusive. It was in the hope that reliable evidence one 
way or the other could be obtained, that the following series of experiments have 
been, during the past five months, carried on, and which I now venture to place 
before you :— 
* ¢ “4 4 . to 6f, * 
Tulasne—‘‘ Second Mémoire sur les Médinées et les Ustilaginées.” ‘Ann. des Sciences 
Nat,” 4 series, vol. ii., p. 116. 
+ Cooke—Handbook of British Fungi, p. 498. 
ee 
