40 British Uredinccs and Ustilas:inecs. 



when it occurs on various species of Hordeum, consists 

 almost entirely of mesospores { = P. anomala, Rost). An 

 American species produces bicellular spores in the summer 

 (= P. vexans, Farl.), and subsequently mesospores only 

 (= Uromyces brandegei, Peck). The brown colouration of 

 the membrane of P.graminis is sometimes abnormally con- 

 fined to the pedicel, the spore remaining colourless. This 

 condition I first observed in some specimens sent me by Mr. 

 W. Marshall, from near Ely. I have also seen it in Aus- 

 tralian specimens. Upon the other hand, instead of spores 

 being bicellular, they are sometimes variously complex, 

 triseptate, or even quadriseptate ; or the upper or lower 

 cell may be longitudinally or obliquely septate, which is 

 the normal condition of the spores of Triphragmium, 

 Greville * figures this condition as P. variabilis. This 

 septation is purely accidental, occurring in one spore-bed, 

 but not in any of the others on the same plant. Mr. Vize 

 and Professor Trail have met with this condition in P. 

 bidlata, and the Rev. Dr. Keith in P. lychnidearum. I 

 have seen it in one of the graminaceous species on Loliiini 

 perenne, and Mr. Grove in Pnccinia betoinccB. 



The teleutospores of Phragmidium and Xenodochus 

 differ from those of Puccinia in being composed of a 

 greater number of elementary spores, which are developed 

 from above downwards (basipetal formation). The dilated 

 upper end of the hypha becomes full of coarsely granular 

 protoplasm ; delicate septa appear from above down- 

 wards. The protoplasm thus differentiated is soon seen 

 to be surrounded by a cell-wall (endospore), which at 

 this stage of its development is considerably smaller 

 than the compartment in which it is situated ; so that the 

 young spores are obviously, in structure, individually dis- 

 tinct from one another. The uppermost spore is usually 



* Greville, " Scot. Crypt. Flora," t. 75. 



