ROSA PRATINCOLA GREENE 305 



different years between 1873 and 1896, without having seen the 

 original R. Arkansana, I entertain a suspicion that it may have 

 been founded on some corymbosely-flowering precocious shoot of 

 the so-called R. blanda of that region, or perhaps of R. Fendleri. But 

 apart from the antecedent probability of this our eastern prairie 

 species being also an inhabitant of a cactus desert, the western and 

 xerophilous rose, the real R. Arkansana is glabrous, while ours is 

 pubescent ; it has stipules both glandular and prickly, while ours 

 has them softly pubescent only; it has sepals reflexed in fruit, 

 while in ours these are erect." 



It will be noted that the above descriptions differ principally in 

 the number and surface of the leaflets, the position of the sepals, 

 and the surface of the stipules. After a study of the roses of 

 Iowa it was found that both descriptions were needed; for, there 

 are prickly and deciduously-prickly stems ; plants with seven to 

 eleven and nine to eleven leaflets ; leaf surfaces as Greene describes 

 them but some glabrous above and below ; there are connivent and 

 spreading sepals ; and stipules with entire, glandular-toothed and 

 glandular-hispid margins. However, on account of the promiscuous 

 variation, which will be discussed later, one cannot recognize two 

 species. 



The description of R. pratincola in the seventh edition of Gray's 

 manual differs from that of Greene's as follows: 



Greene Gray 



1. Stipules; entire More or less toothed 



2. Sepals; glandular-hispid Rarely hispid 



3. Rhachis; often setose-prickly Softly and finely villous or tomen- 



tulose, glandular hairs occasional 

 or none. 



The R. pratincola of Britton and Brown has spreading, sparingly 

 glandular hispid calyx-lobes, stipules that are in some cases toothed, 

 and leaflets glabrous on both sides. 



These inconsistencies in the descriptions of the various authors 

 suggested variability in the plants themselves. Accordingly an in- 

 vestigation of the extent of variation was made. 



A part of the material used for this work was collected during the 

 summer of 1918 from Dickinson and Buena Vista counties. Pro- 

 fessor Shimek's extensive collection and the material of the her- 

 barium of the State University of Iowa also were used. 



The writer wishes to here acknowledge her indebtedness and 

 gratitude to Professor Shimek for his helpful suggestions and kind 

 criticism in the preparation of this paper. 



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