CHAPTER V. COMPARATIVE REVIEW. UREDINEAE 2JJ 



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 1 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. Schroter 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 P'irst Edition, p. 169. 



