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1903] RAVEN ELT AS OF THE UNITED STATES 1 15 



nelia) includes all species in which all the teleutospores in a 

 head are one-celled; the second section (Pleoravenelia) includes 

 all species in which the inner teleutospores of a head are two- 

 celled. As a matter of convenience it seems desirable to recog- 

 nize these two sections as distinct genera. 



KEY TO GENERA. 



All teleutospores in a head one-celled ; aecidia when present with a 



well developed pseudoperidium ----- Raveneiia 

 Inner teleutospores in a head two-celled ; aecidia as in Ravene- 



iia 



Pleoravenelia 



All teleutospores in a head one-celled ; aecidia without a pseudo- 



I pendium 



Neoravenelia 



RAVENELIA Berk. 



Berkley, Gardeners' Chronicle 10; 132. i853, 



Parker, The Morphology of Raveneiia glanduliformis, Proc. Amer. Acad. 



22: 205-217. 1886. 

 Cooke, The genus Raveneiia. Jour. Roy. Micr. Soc. 3 : 384. 1880. 

 DuGGAR, Germination of the teleutospores of Raveneiia cassiaecola, BOT. 



Gaz. 17: 144-148. 1892. 

 Dietel, Die Gattung Raveneiia. Hedwigia 33:22-69, 367-371- 1894; 

 Engler and Prantl. Nat. Pflanz. 11: 73-75. 1897-1901. 



Spermogonia formed between the cuticle and the epidermal 

 cells, hemispherical. Aecidia with a well developed pseudo- 

 peridium. Uredospores borne singly on short stalks, with germ 

 pores few or many; paraphyses usually present in the uredo- 

 sori, Teleutospores united into cushion-like heads, formed of 

 several or many cells; all teleutospores in a head one-celled; 

 attached to the under side of the heads are several to many 

 hyaline cells or cysts ; pedicel of the head composed of several 

 hyphae, which are either united into a compound stipe or sep- 



arate. 



KEY TO species. 



I. Teleutospore heads smooth 



2 



Teleutospore heads rough, spinous, warty, etc. - - - - 8 



2. Uredospore germ pores many, scattered 



3 



Uredospore germ pores equatorial in one row - - - - 5 



Uredospore germ pores in two rows - - - " ' ^ " 

 Uredospores unknown --*"■"'' 



3- Sori sub-cuticular ; cysts pendent 



7 



4 



