BY D. McALPINE. 
467 
and teleutospores, but on this view they ought to be more general 
and not confined to individual species. 
P. Magnus* considers, on the other hand, that the uredospores 
have developed out of teleutospores on account of their better 
adaptation for germination and dissemination, and that those 
species which have no uredospores never acquired the property of 
forming them. 
Dr. Plowrightf considers them as morphologically analogous to 
the teleutospores of Uromyces, somewhat similar to the view of 
Tulasne,J who regards them as reduced teleutospores, the reduc- 
tion being brought about by the abortion of the lower cell and 
thus the genus Uromyces, characterised by such spores, is to be 
considered a degraded form of Puccinia. There are other con- 
siderations, however, such as the nature of the host-plants, which 
would seem to point to the Uromyces as being rudimentary and 
not reduced forms of Puccinia. 
In Puccini pruni, Pers., the two cells of the teleutospores 
readily separate and the lower cell is often imperfectly developed, 
so that the connection between Uromyces and Puccinia seems to 
be shown here. In fact, it would appear that even the eminent 
mycologist Dr. Cooke was misled by this resemblance when he 
named this very species, sent from Australia on peach and 
almond leaves, as Uromyces amygdali. And if this relationship 
is accepted, then the term mesospore, as indicating a transition- 
form between two other kinds of spore, is inappropriate, as it is 
really between the two genera. 
Just as the unicellular or Uromyces-like spore links the 
Puccinia on to lower but not necessarily earlier forms, so the 
multicellular spore foreshadows the more advanced forms of the 
Uredines, such genera as Triphragmium in which the teleutospore 
is normally three-celled, and Phragmidlum, in which it may 
consist of from three to ten superimposed cells. And thus close 
* Ber. Deutsch. Bot. Gesell. ix. (1891). 
t Brit. Ured. and Ustilag. p. 39 (1889). 
% Ann. Sci. Nat. 4 Ser. Vol. ii. p. 145 (1851). 
