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1902] ROCKY MOUNTAIN PLANTS . 359 



son, Bull. Torr. Bot. Club 25:203. — In this species we have one 

 of the most variable plants in respect to habit and size that has 

 ever come under mj observation. The original Nuttallian form 

 is small and erect, but the large number of specimens at hand 

 seem to furnish a complete series leading up to the other extreme 

 represented by the large ** tumble weed," often a meter in diame- 

 , ter, that was described as A. voUUans, The distinctions as to 



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the fruit characters are not sufficiently marked to maintain the 

 latter as a species. ^ Its polymorphism is correlated with its 

 wide range. 



J Atriplex PowELLii Wats. Proc. Am. Acad. 9:115. — Though 



this species is accredited to S. W. Colorado by Coulter's Manuiil, 

 I am not sure that it rests upon any specimens except the type, 

 which was grown under cultivation from seeds obtained from 

 Arizona. 



Atriplex Wolfii Wats, Proc. Am. Acad. 9:1 12. — This 

 excellent species is still quite rare in herbaria, all the specimens 

 seen by me being from Colorado. Allied to it but quite dis- 

 tinct, as wull be seen, is the following : 



Atriplex tenuissima, n. sp. — Annual, branched from near the 



' base, the slender branches racemosely branched into filiform 



branchlets, 2-3*^"^ high, moderately white-scurfy throughout: 

 leaves numerous, bract-like, oblong to lance-ovate or broader, 

 j_^ mm long: floriferous from near the base; the few-flowerd 



(1-3?) clusters axillary (pistillate plant the only one seen): 

 fruiting bracts very small, mostly less than 2 ""^ long, triangular- 

 ovate, completely united, forming a subpyramidal fruit irregularly 

 and rather numerously tuberculate below the middle. 



This proposed species is based upon a specimen in the Herbarium of the 

 Missouri Botanical Garden, M, E, Jones 6525, Gunnison, Utah, Sept. 15, 

 Igoo, altitude about 1600 ". Distributed as^. WoIJii, to which it has some 

 resemblance in habit, but the foliage and fruit are very distinct. 



Atriplex SACCARiA Wats, Proc. Am. Acad. 9:112. — During 

 several years of collecting in southern Wyoming", nothing answer- 

 ing to this description has yet been encountered, in this the 

 supposed type locality. It seems barely possible that the species 

 rests upon one of the numerous v^ariations of the following: 



3 See Mr. G.N. Collin's valuable bulletin cited in the preceding footnote. 



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