92 UROMYCES 
the leaves. The mycelium of the ecidial stage is said to be perennial in 
the host; Dietel says that in some localities the scidiospores can re- 
produce themselves, and that then the uredo is suppressed. 
Both this species and the preceding are distinguished from U. flectens 
in the fact that the sori are smaller, distributed more uniformly over the 
leaf, and do not cause distortions. 
The zcidium is rare in Britain (I have seen specimens only from Perth) ; 
most of our records of Uromyces on T. repens belong to the following 
common species, U. flectens. Pseudopeziza, Trifolii (a Discomycete) is 
common on leaves of white clover and is not infrequently mistaken for 
the uredo-stage of U. Trifolii-repentis, but is distinguishable by its being 
confined to the wpper surface of the leaves. No practical means of 
prevention are known for either the Clover Rust (Uromyces) or the Clover 
Leaf-spot (Pseudopeziza). 
DISTRIBUTION: Europe, Asia Minor, Persia, North and 
South America, Australia. 
7, Uromyces flectens Lagerh. 
Uromyces flectens Lagerh, Svensk Bot. Tidskrift, iii. 36. Sydow, 
Monogr. ii. 360. Grove, Journ. Bot. 1911, p. 366. 
Puecinia neurophila De Toni, Sacc. Syll. vii. 698. 
Leleutospores. Sori hypophyllous, or more often on the 
nerves and petioles where they cause swell- 
ings and distortion, scattered, rather large, 
4—2 mm. long or even confluent and larger, 
long covered by the epidermis, then pul- 
= verulent, dark-brown; spores as in U. 
Fig. 44. U. flectens. TOON TEDENDS. 
Teleutospores on 1’. On Trifolium repens. May—October. 
repens. Common. (Fig. 44.) 
It has been frequently noticed that the Uromyces on Trifolium repens 
behaves differently in different localities ; sometimes forming teleutospores 
only, from May to October; at others forming both ecidia and uredospores 
during the same time. Plowright records an interesting experiment which 
he performed (Ured. p. 125) ; in October he brought a plant of 7. repens, 
with the Uromyces upon it, indoors and kept it there till the following 
summer. During all this time it produced only teleutospores. Lagerheim, 
in 1909, noticing that the form which produced only teleutospores had 
sori which were larger, more predominant upon nerves and petioles, and 
remained longer covered by the epidermis, described this as a distinct 
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