BlasdaLe: Uredinales of California ' 111 



The genetic connection between the two stages was first established 

 by Arthur (Mycologia, vol. 1, p. 252, 1909, vol. 4, p. 57, 1912), who 

 succeeded in growing aecia on Crategus PringUi Sarg. from telia 

 obtained from Corvallis, Oregon. From the latter state it is reported 

 to be a rather serious pest by O'Gara (Science, vol. 39, p. 60, 1914), 

 and by Jackson (Phytopathology, vol. 4, pp. 41, 261), attacking 

 especially pears, quinces, and certain varieties of apples. 



19. Gymnosporangium Harknessianum (Ell. and Ev.) Kern. I, 



III 



Bull. N. Y. Bot. Gard., vol. 7, p. 441, 1911. 



Aecia on Amelanchier alnifolia Nutt., Klamath Kiver (Harkness), 

 Plumas County (Meinicke). 



What is believed to be the telial stage of this species has been col- 

 lected by Meinicke on Juniperus occidentalis Hook., near Clio, Plumas 

 County. 



20. Gymnosporangium koreaense (P. Hennings) Jackson. I, III 



Jour. Agr. Ees., vol. 5, p. 1006, 1916. 



Aecia on leaves of an ornamental species of Pyrus from a nursery 

 near Oakland (D. P. T. MacDonald), but not otherwise reported from 

 the state. 



Telia not reported from California, but found in Oregon on Juni- 

 perus chinensis Lindl. (Jackson). 



HYALOPSORA MAGN. 

 Ber. deut. bot. Ges., vol. 19, p. 582, 1901. 



Aecia without peridium not conspicuous, irregularly dehiscent; 

 aeciospores borne singly on pedicels, colorless. Uredinia with globoid 

 peridium. Telia scattered, indehiscent; teliospores globoid, usually 

 four-celled, colorless, wall thin and smooth. 



21. Hyalopsora Cheilanthis (Peck) Arthur. II 



Bull. Torr. Club, vol. 10, p. 62, 1883 ; Arthur, N. A. Flora, vol. 7, p. 113, 

 1907. 



On Pellaea andromeda folia Kaulf., San Gabriel Canon (Leroy 

 Abrams) ; on Ceratopteris triangularis (Kaulf.) Underwood, Pasa- 

 dena, type of Uredo pasadetiae Sydow (McClatchie), Mount Tamal- 

 pais; Julian, San Diego County (Bethel). 



