Rydberg : Studies on the Rocky Mountain Flora 620 



arrangement of the involucral bracts in distinct vertical rows. It 

 grows in gravelly places in northern Wyoming, at an altitude of 

 2000-2500 m. 



SIDERANTHUS Fraser 

 The name SiderantJms appears first in Fraser's Catalogue, but 

 there only as a nomen nudum. Pursh in his Flora on page 750 gives 

 SidcniiitJius intcgrifolius Fraser and ^. pinnatifidus Fraser as syno- 

 nyms o{ Aviclliis 7'illosus and A. spinuloses described on page 564. 

 There may be a doubt as to which of these should be regarded as 

 the type of SidcrantJuts. Anicllus villosns with its relatives was 

 made a genus Clirysopsis by Nuttall in 18 18 or by Elliott in 

 1824, according to different interpretations, long before Eriocarpimi 

 was established (1840). This leaves SiderantJms pinnatifidus as 

 the residue of the genus Sidcranthus. Besides Nuttall, who was 

 the real author of Fraser's Catalogue, made Sidcrantiuis a subgenus 

 of Dictcria containing the only species D. spinulosa {Aplopappus 

 spinu/osus DC. See Trans. Am. Phil. Soc. II. 7 : 301) ; and thus 

 shows that he regarded it as the type of SiderantJius.''^ 



Leaves spinescent toothed, not pinnatitld. 



Heads discoid ; perennial with woody caudex. I. S. grindelioides. 



Heads radiate ; annual. 2. S. rtibigiiiosus. 



Leaves pinnatifid. 



Stem more or less floccose, or cinereous especially when young. 



Plant cinereous pubescent, more or less glandular. 3. .S". atistralis. 



Plant more or less floccose, not at all glandular. 4. S. spiiiulosiis. 



Plant neither floccose nor cinereous. 



Plant perfectly glabrous or sparingly glandular puberulent. 



5. S. glabcrriiiius. 

 Plant finely puberulent. 



Heads hemispherical ; bracts slightly glandular. 6. S. pitberulits. 



Heads somewhat turbinate ; bracts densely glandular pulierulent. 



7. .S". turbineUus. 



I. Sideranthus grindelioides (Nutt.) Britton 



Eriocarpuui grindelioides Nutt. Trans. Am. Phil. Soc. II. 7 : 

 321. 1840. 



Aplopappus Nuttallii Torr. & Gray, Fl. N. A. 2 : 240. 1842. 



* Professor Greene (Piltonia 2: 115) seems to think Sideraitthus is derived from 

 the Latin sidus, star, and the Greek, av&og, flower. It is better to regard the first part 

 also as Greek, Gl(5r/f)0Cj iron. Why accuse Nuttall of making a hybrid word, which 

 we would not permit ourselves? 



