CHAPTER V.—COMPARATIVE REVIEW.—UREDINEAE 77 
The sterigmata are shortly subulate unicellular hyphal branches. They abjoint at 
their apex in basipetal order a succession of narrowly ellipsoidal spermatia wrapped 
in a mucilage and forming a single row. The morphological characters of these 
bodies which have been ascertained are the same as those described above in Collema, 
&c. They collect in the cavity of the spermogonium and are discharged through its 
mouth, when the investing mucilage swells by accession of moisture. Like the 
' spermatia of the Ascomycetes, they have never been known to germinate. 
Small deviations from the above arrangements have been observed; in some 
species the spermogonia are formed on the outer surface of the epidermis, only covered 
by the cuticle, through which they ultimately force their orifice, as in Puccinia 
Anemones, Peridermium elatinum and Phragmidium, and hence they have a flatter 
basal surface ; in others the paraphyses at the orifice do not protrude beyond the epi- 
dermis, as in Chrysomyxa, or are entirely wanting, as in Phragmidium. The sper- 
mogonia dry up when they have discharged their spermatia, and their colour, which 
is at first yellow or reddish yellow, changes to brown. 
The spermogonia, where they occur, are always the precursors of the aecidia 
which belong to them, that is, they are always present in a fully developed state when 
the first beginnings of the aecidia make their appearance in their neighbourhood. 
All these facts point to a physiological relation of the two organs to one another 
similar to that which exists between the spermogonia and sporocarps of the 
Collemeae. But a more certain proof of this relation is still wanting; the organs in 
question must therefore for the present be classed with those in which the 
physiological import is doubtful. 
It was conjectured that in the Uredineae as in the Ascomycetes the spermatia were 
sexual fertilising organs, as soon as it was understood that the spermogonia are parts 
of the species which form aecidia, and do not represent, as their discoverer Unger 
supposed, distinct species of Fungi. The arguments for that conjecture were and are 
the same as those which have been discussed in connection with the Ascomycetes ; 
this is sufficiently apparent from the foregoing statements, and they need not be 
repeated. Further reflection suggested that only the sporocarps known as aecidia 
and no other bodies could be the products of the presumed fertilisation, because it 
is the aecidia which are almost always preceded by the formation of spermogonia and 
spermatia. But there have always been minor objections to this view. In some cases 
spermogonia occur as the companions or precursors, not of the aecidia, but of gonidio- 
phores, the layers of the uredospores and teuleutospores which will be described 
presently. This is the case in Puccinia fusca (Anemones), P. suaveolens and some 
others, but it occurs only in some particular species and the objections founded on it 
are easily met by the suggestion that in these species we have to do with the male 
gonidia-forming plants of dioecious species, while the female plants occur perhaps 
elsewhere or for some reason are not known. Again, I have given’ a description of 
a case in which Endophyllum sempervivi, which usually forms spermogonia in the 
ordinary way, produced aecidia with normally developed and fertile spores on plants 
cultivated in perfect isolation, without any spermogonia or spermatia being found 
upon them. Schröter found the aecidia on some cultivated specimens of Puccinia 
Alliorum always unaccompanied by spermogonia; in Puccinia Galiorum on Galium 
Aparine, and in Uromyces Viciae Fabae on Ervum hirsutum, spermogonia were 
constant in the spring, but in the later part of the year there was a copious formation 

1 First Edition, p. 169. 
