136 
MILDEWS, RUSTS AND SMUTS 
clusters, often running into each other, very minute, circular, 
soon naked and powdery, dusky brown, on pale spots on the 
under surface of the leaf ; spores elliptical, ovate or oblong, 
tip broadly rounded, not thickened, base rounded or very 
slightly narrowed, smooth or very minutely punctate, 
brown, 30—^40 X 18—25 [a, pedicel colourless, short, 
deciduous. 
On Polygonum viviparum and P. histofta. Britain, 
Europe, Korea, and N. America. 
Puceinia acetosae, Koern. 
Uredospores. Sori on both sides of the leaf, most fre¬ 
quently on the upper surface, sometimes on the stem, scat¬ 
tered, minute, circular, powdery, rusty brown ; spores 
globose, elliptical or pear-shaped, echinulate, brownish, 
24—40 X 20—25 [a. 
Teleutospores. vSori resembling those of the uredospores, 
minute, circular, or elongated on the stem, dusky brown ; 
spores ovoid, elliptical, oblong or somewhat club-shaped, 
ends rounded, or very slightly narrowed at the base, tip 
scarcely thickened, slightly constricted at the septum, very 
minutely warted, chestnut-brown, 30—50 X 20—30 (a, 
pedicel colourless, slender, deciduous. 
On Rumex acetosa and R. acetosella. Britain, Europe 
generally, Siberia and N. America. 
ARISTOLOCHIACEAE 
ASARUM 
Piiccinia asarina, Kunze, Plowr., Ured., p. 202. 
Teleutospores. Sori present on both surfaces of the leaf, 
arranged in circular clusters, often crowded, on large yel¬ 
lowish-brown spots, often in circles, minute, surrounded 
by the torn epidermis, blackish ; spores oblong, ovate or 
soiuewhtat spindle-shaped, tip more or less conical, thick¬ 
ened, paler, slightly constricted at the septum, narrowed 
towards the base, smooth, 3^ellowish-brown, 36—50 X 
15—25 [a, pedicel, colourless, deciduous. 
On Asarum europaeiim. Britain, Europe generally, 
and N. America. 
SANTALACEAE 
THESIUM 
Puceinia thesii, Chaill.; Plowr., Ured., p. 145. 
Pycnidia. On both sides of the leaf, numerous, mixed 
with the aecidia. 
