1922-23.] BOTANICAL SOCIETY OF EDINBURGH 165 



germ-pores (figs. 2 and 3). The walls are unusually thick, 

 and in consequence the spores bear some resemblance to 

 unicellular teleutospores ; in consequence, the species was 

 originally incorrectly placed in the genus Uromyces as U. 

 sanguineus. 



The teleutospores possess unusually long pedicels, and in 

 consequence project beyond the uredospores in the sorus. 

 The pedicel is hyaline up to 200 fx long, and throughout 

 almost the whole of its length the walls are so thick that 

 the cell cavity is occluded. At the base, where the pedicel is 

 often swollen, the walls are much thinner and the cell cavity 

 is obvious (fig. 6). The wall consists of four layers. The 

 innermost, next to the contents, is thin and dark coloured, 

 and immediately out'^ide this is the thick browm warted layer. 

 This is followed by a hyaline layer, seen particularly at the 

 apex and sides, and on the surface there is a very fine cuti- 

 cularised layer. Two germ-pores are present in each cell, 

 situated usually about the middle of the lateral walls ; all 

 the germ-pores usually lie in the same plane (figs. 5 and 8). 

 The teleutospores average 35 x 24 /z. 



In many cases the pedicel is not attached exactly at the 

 base of the spore (figs. 6 and 10), and in a few cases the attach- 

 ment is at the side of one cell, so that the longitudinal axis of 

 the spore is at right angles to the pedicel (fig. 7). The peculiar 

 three- and four-celled teleutospores described by Blasdale ^ 

 were not observed. 



Germination takes place within twenty-four hours when 

 the spores are placed in water. The uredospore usually 

 produces two germ-tubes, which generally soon give rise to 

 two or three branches (fig. 4). The teleutospore, on germina- 

 tion, produces one germ-tube from each cell, and these may be 

 either on the same or on opposite sides of the spore (figs. 9 

 and 10). Sporidia were not produced in the hanging drops. 



On account of the structure of the wall of the teleutospore 

 and the presence of two germ-pores in each cell, this rust was 

 removed from Puccinia by Magnus ^ and placed in the genus 

 Urojjyxis, Schrot. Sydow,^ however, considers that Uropyxis 



^ Loc. cit. 



- tJher die Gattung Urojiyxis, Ber. d. deutsch. bot. Ges., xvii, 1899, 

 p. 119. 



^ Monographia Uredinearum, vol. i, p. 844. 



