98 
MILDEWS, RUSTS AND SMUTS 
not forming spots, on both surfaces of the leaf ; spores 
globose or subglobose, very minutely echinulate, pale brown, 
24—^30 X 20—25 p. 
Teleutospores. Sori minute, scattered, powdery, blackish, 
not forming spots, on both sides of the leaf ; spores elliptical 
or ovate-oblong, tip rounded, not thickened, scarcely or 
not at all constricted at the septum, very minutely warted, 
brown, 26—^40 x 16—22 p, pedicel short. 
On leaves of Carlina acaulis. Britain, Europe generally, 
except France. 
CENTAUREA 
Puccinia cyani, Pass. 
Uredospores. Sori usually on the under side of the leaf, 
not forming spots, minute, scattered or crowded, circular 
or elliptical, cinnamon colour, becoming powdery ; spores 
globose, subglobose or broadly ovate, minutely echinulate, 
yellowish-brown, 20—30 x 19—24 p. 
Teleutospores. Sori present on both sides of the leaf, 
scattered, minute, dot-like, dusky brown, becoming pow¬ 
dery ; spores broadly elliptical, rounded at both ends, 
apex not thickened, not constricted at the septum, very 
minutely v/arted, chestnut-brown, 30—35 x 22—27 p ; 
rarely up to 40 p long ; pedicel colourless, short. 
Syn. Uredo cyani, Schleich. 
Puccinia suaveolens, forma cyani, Wallr. ; Plowr., 
Brit. Ured., p. 183. 
Parasitic on living leaves and stem of Centaurea cyanea. 
Britain, Europe generally. 
There are two generations during the year in this species. 
The perennial mycelium in the persistent portions of the 
host-plant, grows up along with the above-ground parts 
of the host, and becomes generally diffused, and gives 
origin to the first generation of uredo and teleutospores. 
Those of the second generation, appearing later in the 
season, are due to infection by uredospores of the first 
generation. The mycelium of the second generation is 
localised. 
The uredospores have two equatorial germ-pores. 
Puccinia centaureae, Mart. ; Plowr., Ured., p. 186. 
Pycnidia. Grouped on yellow spots, circular on the 
leaves, elongated and bounded by a purple line on the 
leafstalks. 
Uredospores. Sori minute, scattered or clustered, often 
on yellowish spots, powdery, brown ; spores subglobose 
