230 



MANUAL OF POISONOUS PLANTS 



known as sporidia. Acording to Dr. J. C. Arthur, it is undoubtedly connected 

 with an aecidium on Oxalis corniculata. 



Distribution and hosts. Common wherever corn is cultivated and according 

 or Carelton, also upon teosinte. 



Fig. 66. Corn rust 

 (Puccinia Sorghi) on 

 corn. Winter spores. 



Uromyces. Link. Clover Rust 



Aecidiospores in cup-like bodies with an evident pseudoperidium ; uredo- 

 sori powdery; uredosDores 1 -celled with several evident germ pores; teleutosori 

 powdery; teleutospores 1-celled, separate, pedicellate, apex with a single germ 

 pore; sporidia flattened on one side. About 250 species widely distributed. 

 Many of the species produce serious diseases of cultivated plants, as Uromyces 

 pisi upon the pea, the alfalfa rust, (U. striatus,) and the bean rust, ( U. ap- 

 pendiculatus (Pers. Lev.) There are many other species found upon our wild 

 plants. Some of these, when they occur upon forage plants, may cause mycotic 

 stomatitis. 



Uromyces Trifolii. (Hedw.) Lev. 



Aecidia in circular areas of pale colored spots ; pseudoperidia short, cylin- 

 drical, flattish ; edges, whitish, torn ; spores sub-globose or irregular, finely 

 roughened, pale orange ; 14-23 M in diameter ; uredosori pale brown, round, 

 scattered, surrounded by the torn epidermis; spores round or ovate, roughened; 

 20-26x18-20 M with 3 or 4 germ pores; color brown; teleutosori small round 

 almost black; long covered by the epidermis; spores globose, elliptical or sub- 

 pyriform occasionally with wart-like swellings on the summit 15-20x22-30 m; 

 small dark brown in color ; pedicels long. 



Distribution. Widely distributed upon various clovers, especially red clover 

 and the white clover. So abundant is this fungus at times that the plants are 

 covered with the brown dusty material. Miss Howell reports it as very severe 

 in the state of New York at times. The writer commenting on this fungus 

 some years ago. said : 



The fungus did not occur until August and only on the "rowen" or "aftermath." 

 Later it was found quite abundantly on the campus and. College Farm. So severely did 

 it attack some of the plants, especially the stems and leaves, that in touching the plants, 

 the hands became covered with brown spores. 



