THE FUNGI WHICH CAUSE PLANT DISEASE 



383 



The secial stage of the former of these is not known. Its uredinia 

 survive the severest winters even so far north as the Dakotas. 



P. coronata Cda."^' 2^«- ^ 



I (=iE. rhamni). Peridia often on very large orange swellings, 

 causing great distortions on the leaves and peduncles, cylindrical, 

 with whitish torn edges. Spores subglobose, very finely verrucose, 

 orange-yellow, 15-25 x 12-18 fi. 



II. Uredinia orange, pXilverulent, elongated or linear, often con- 

 fluent. Spores globose or ovate, with three or four germ pores, 

 echinulate, orange-yellow, 20-28 x 15-20 m- 



III. Telia persistent, black, linear, often confluent, long 

 covered by the epidermis. Spores subcylindrical or cuneiform, 

 attenuated below, constriction slight or absent, apex truncate, 



M m mi ¥^ mf w 



Fig. 276. — P. coronata, various teliospore forms. After Bolley. 



somewhat thickened, with six or seven curved blunt processes, 

 brown, 40-60 x 12-20 /i- Pedicels short, thick. 



Heteroecious; I, on Rhanmus frangula. 



II and III on various grasses but not on oats. 



From this form as earlier imderstood Klebahn has separated 

 P. coronifera Kleb. on evidence derived from inoculations, and 

 made the latter to include these forms with the secial stage on 

 Rhamnus cathartica and the uredinial and telial stages on Avena, 

 Lolium, Festuca, Holchus, Alopecurus and Glyceria. P. coronifera 

 has been still further divided by Eriksson into eight biologic forms 

 and P. coronata into three such forms.'"^ 



P. glumarum (Schm.) Er. & Hu.^^*' *™ is widely distributed on 

 wheat, rye, barley and a few other grasses in India and Europe 

 but is not known in America.'"* Its aecia are not known. By 

 some this is regarded as a race of P. rubigo-vera. Both 

 uredinia and teliospores have been reported in the pericarp of 

 grains.'* 



