Oct. 15, 1921 



Aecial Stage of the Orange Leaf rust of Wheat 



163 



These were each sown upon the variety of wheat known as Dawson 

 Golden ChaflF, and in all cases positive infection was obtained followed by 

 the development of uredinia which were typical of Puccinia triticina. 



Sowings of aeciospores also were made upon a number of grasses. 

 Aecia which were produced from telia obtained from Hickory, N. C, 

 Canton, Miss., and Moscow, Idaho, were used and Table IV gives the 

 results. 



Table IV. — Results obtained in ig20 from sowing the aeciospores of Puccinia triticina 

 produced from telia obtained in three different areas, on wheat and related grasses 



Host inoculated. 



Arrhenatherum elatius (L.) Mert & Koch. . . 



Agropyron caninum (L.) Beauv 



Agropyon cristatum Beauv 



Agropyron desertorum Schult 



Agropyron in£rme (Schribn. & Sm.) Rydb . 



Agropyron repens (L.) Beauv 



Agropyron tenerum Vasey 



Elymus atistralis Schribn. & Ball 



Elynius canadensis L 



Elymus glaucus Buckl 



Elym^us triticoides Buckl 



Elymus virginicus L 



Hordeum caespitosum Schribn 



Hordeum gu^soneanum Pari 



Hordeum jubatum L 



Hordeum pusillum Nutt 



Hordeum inurinum I, 



Hordeum vulgare L 



Hystrix Hystrix (L.) Millsp 



Notholcus lanatus (L.) Nash 



Secale cereale L 



Sitanion Hystrix (Nutt.) J. G. Sm. 



Triticum aegilops Beauv 



Triticum aestivum L 



Number and source of aecia. 



No. 7219 

 (N.C.). 



t Many. 



No. 8719 

 (Miss.). 



t One ure- 

 dinium. 



t Many. 



No. 12519 

 (Idaho). 



t Few. 

 t Many, 



— No infection. 



t Uredinia produced. 



Except for the one uredinium produced on Secale cereale, Triticum 

 aestivum and T. aegilops were the only species infected 



DESCRIPTION OF AECIA 



The following description has been drawn from the aecia obtained 

 in the cultures discussed above. 



Pycnia amphigenous, mostly epiphyllous, numerous, crowded upon 

 more or less swollen reddish brown to yellowish areas 2 to 15 mm. in 

 diameter, conspicuous, subepidermal, honey-yellow, globoid or flattened 

 globoid, 80 to 145 /i broad by 80 to 130 fx high; ostiolar filaments 95 to 

 190 jj, long, agglutinated to form a prominent, broad column. 

 65508°— 21 4 



V 



