ITREDINB^. 



[ 792 j 



UREDINE^. 



Fig. 773. 



These constitute the genera of the family 

 Uredinei. 



Of the genus Phraf/midimn, P. buJbosuin 

 (Piiceinia ruhi, Schfer.) is a species com- 

 monly occurring on the leaves of brambles, 

 forming reddish, then orange, and finally 

 blackish rusty spots (fig. 773). The first 

 signs of reproductiTC organs appear in the 

 middle of the spots on the upper face of 

 the leaf, consisting of a few minute unilocu- 

 lar cavities {spermoyoma) excavated in the 

 leaf, with a little flat ostiole ; in these 

 occur ovate s})er- 

 matia (see ^ci- 

 dixtm), which are 

 accompanied by a 

 yellowish mucous 

 liquid, and are ex- 

 pelled with this in 

 the form of drops. 

 Subsequently to 

 this, the tlredo- 

 fruits are deve- 

 loped, mostly on 

 the lower face of 

 the leaf, at the back 

 of the sperm ogonia, 

 or more rarelj' on 

 the upper face, in a 

 circle around them. 

 They are pulvei'u- 

 leut patches (fig. 

 773), solitary or a few together ; and a ver- 

 tical section (fig. 774) shows them to con- 

 sist of paraphyses (fig. 775), and simple or 

 branched short filaments bearing globose 

 stylospores (fig. 776), which soon become 

 detached, and in ripening acquire an echi- 

 nate outer coat with numerous pores. 



Fig. 774. 



Fig. 776. 



Leaf of bramble, 

 " Ureclo ruborum." 

 the nat. size. 



with 

 Half 



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

 physes and imperfect stylospores, Magn. 460 diams. 



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 fiiee 

 of the leaf) iu the form represented in fig. 



Fig. 775. Separate paraphyses. 



Fig. 776. Detached pedicels with stylospores. 



Magnified 460 diameters. 



Vertical section of the sorus of " Uredo suaveolens,' 

 with immature stylospores. Magnified 460 diameters. 



Eipe stylospores of the same, germinating. 

 Magnified 460 diameters. 



Fig. 779. 



Fig. 780. 



Deformed styloepores, with the spinuloae coat deve- 

 loped. Magnified 460 diameters. 



