UREDINEI. 



[ 661 ] 



UREDINEI. 



has been in print, Tulasne has pubhshed an 

 elaborate memoir upon the Uredinei and 

 Ustilaginei, which renders it necessary to 

 devote considerable space to the present 

 article, which, with that of Ustilaginei, 

 must be regarded as superseding what was 

 stated under the head of CiEOMACEi. 



Under the head of Ustilaginei are placed 

 the various forms of hunt, caries, &c., which 

 affect the ovaries and anthers of Flowering 

 plants, growing in the interior of these or- 

 gans, causing them to become more or less 

 deformed, and finally occupying the whole 

 of their interior as a pulverulent substance, 

 commonly of a black colour, and sometimes 

 with a foetid odom- (see Ustilaginei). 



The genus Uredo is shown by Tulasne to 

 have no satisfactory claim to a distinct exist- 

 ence, since the structures which have repre- 

 sented it appear to be merely a form of the 

 reproductive organs common to a number of 

 plants, which, in their most perfect state, 

 represent the genera Pucciuia, Phragmidium, 

 Uromyces, &c. 



Of the genus Phragmidium, P. hulbosum 

 [Puccinia Rubi, Schser.) is a species com- 

 monly occurring on the leaves of brambles, 

 forming reddish, then orange, and finally 

 blackish rusty spots 

 (fig. 778). The first 

 signs of reproductive 

 organs appear in the 

 middle of the spots 

 on the upper face of 

 the leaf, consisting 

 of a few minute 

 unilocular cavities 

 {spermogonia) exca- 

 vated in the leaf, 

 with a little flat os- 

 tiole ; in these occur 

 ovate spermatia (see 

 ^cidium), which 

 are accompanied by 

 a yellowish mucous 

 liquid, and are ex- 

 pelled with this in the form of drops. Sub- 

 sequently to this, the UretZo -fruits are de- 

 veloped, mostly on the lower face of the leaf, 

 at the back of the spermogonia, or more 

 rarely on the upper face, in a circle around 

 the latter. They are pulverulent patches 

 (fig. 778), solitary or a few together j and a 

 vertical section (fig. 779) shows them to 

 consist of paraphyses (fig. 780), and simple 

 or branched, short filaments bearing globose 

 stylospores (fig. 781), which soon become 

 detached, and in ripening acquire an echinate 



Leaf of bramble, 

 "Uredo Ruberum." 

 the nat. size. 



with 

 Half 



Fig. 779. 



Vertical section of the same Uredo-fruit, with para- 

 ohj'ses and imperfect stylospores. Magnified 460 diams. 



Fig. 780. Fig. 781. 



Fig. 780. Separate paraphyses. 



Fig. 781. Detached pedicels with stylospores. 



Magnified 46o diameters. 



outer coat with numerous pores. When 

 these germinate, they produce merely a long 

 slightly branched filament. Finally, the 

 perfect fruits [spores) appear on the same or 

 in distinct sori (on the lower face of the leaf), 

 in the form represented in fig. 570 (p. 502). 

 The loculi of these have each three or four 

 pores in the upper part of the side-walls, 

 whence emerge in germination (in spring) 

 short tubular filaments, which soon divide 

 into four cells, from each of which arises a 

 minute "sporidium," borne on a pointed 

 sterigmatous process. 



Puccinia Compositarum exhibits very si- 

 milar phaenomena; its C7rec?o-fruit has been 

 described as Uredo suaveolens. Fig. 782 



Fig. 782. 



Vertical section of the sorus of " Uredo suaveolens," 

 with immature stj'lospores. Magnified 4t)0 diameters. 



