PHRAGMIDIUM 289 



takes place in arctic and alpine Uredinales. As Plowright remarks, the 

 teleutospores can be found in spring on last year's leaves, and germinate 

 readily when placed in water. 



The form on S. Filipenchda, which is very uncommon in this country, 

 differs from that on S. Ulmaria in having the teleutospores usually smooth, 

 and only occasionally provided with a few warts round the germ-pores; 

 hut similar spores may be found on both hosts. In both, some of the 

 spores have three super-imposed cells, as in Phragmidium, also two cells 

 placed as in Puccinia or laterally as in Diorchidium. The uredospores on 

 S. Filipendula are often pyriform and as much as 35 n long ; it may be a 

 distinct species. 



Arthur, who records T. Uhiutriae in the North American Flora on 

 Filipendida rubra, says that it is confined to one locality " of less than 

 a half hectare extent," at Lafayette, Indiana. 



Distribution : Europe, Siberia, Japan, Indiana. 



PHRAGMIDIUM Link. 



Autcecious. 



Spermogones subcuticular, conical or flattened, without 

 ostiolar filaments. Caeomata indefinite, usually encircled by- 

 incurved paraphyses ; spores in chains, each with numerous 

 germ-pores. Uredo-sori definite, usually encircled by para- 

 physes; uredospores borne singly on pedicels, often with 

 paraphyses intermixed, pores numerous, scattered, indistinct. 

 Teleutospores two- to several-celled by transverse septa ; wall 

 thick, laminate, usually coarsely verrucose, the middle layer dark 

 and rigid; pores two or more in each cell, placed laterally; 

 pedicels often swollen below ; basidiospores globose. 



This genus is confined entirely to the family Rosacese. 

 There are many species in North America, but with the 

 exception of P. Poteiitillae and those introduced on cultivated 

 r< >ses they are all different from those of Europe. The warts 

 often found on the outer surface of the teleutospores are due to 

 the contraction of the external gelatinous layer, which can be 

 caused to swell up enormously by boiling in lactic acid. This 

 G. u. 19 



