MILDEWS, RUSTS AND SMUTS 
173 
PHRAGMIDIUM, Link 
Aecidia. Spores in chains, surrounded by paraphyses. 
Uredospores. Forming powdery sori surrounded by 
paraphyses. 
Teleutospores. Spores forming small, black sori, large, 
cylindrical, composed of a single row of cells, 3—12-septate, 
apical cell with one germ-pore, the remainder each with, 
normally, four germ-pores, dark coloured, usually warted, 
pedicel usually long and stout, and swollen at the base. 
There is no true peridium to the aecidia, as in the genus 
Puccinia. The sori of the aecidimn and the uredo stages 
closely resemble each other superhcially, forming yellow 
or orange, powdery patches, the aecidiospores, however, 
are produced in chains, whereas the uredspores are pro¬ 
duced singly on pedicels. The teleutospores are composed 
of a single row of superposed cells, and differ from those of 
Puccinia in always having more than two cells, and in each 
cell, except the terminal one, having four germ-pores. 
Phragmidium is most closely allied to Xenodochus: for 
distinctions consult the last-named genus. 
All the species are parasitic on plants belonging to the 
order Rosaceae. Many so-called species are described 
from various parts of the world, but probably no other 
genus of Uredines is more imperfectly understood, and 
apparently the method of infection experiments, which 
has cleared up so many doubtful points in the genus Puc¬ 
cinia, will alone clear up the tangle. 
Phragmidium violaceiim. Winter; Plowi., XJred., p. 223. 
Aecidium. Sori on the under surface of the leaf, often 
in clusters, causing reddish spots, bounded by a purplish 
border, on corresponding parts of the upper surface of the 
leaf ; spores in chains, globose or broadly elliptical, echinu- 
late, orange-yellow, 12—35 X 16—26 p, paraphyses scanty, 
Uredospores. Sori small, greenish-yellow, powdery; 
spores globose, ovate or broadly elliptical, minutely warted, 
3^ellow, 20—30 [X. 
Teleutospores. Sori on the under surface of the leaf as 
a rule, thickish, black, small; spores cylindrical, 3—4- 
septate, coarsely warted, warts flattened and pale, dark 
brown, tip rounded, usually with quite a small wart-like 
point, 70—120 X 25 —^0 [1, four germ-pores in each cell, 
pedicel long, slightly thickened below. 
Syn. Puccinia viclacea, Schulz. 
Phragmidium asperum, Wallr. 
Lecythea ruhorum, Lev. 
