620 Rydberg: Studies on the Rocky Mountain Flora 



arrangement of the involucral bracts in distinct vertical rows. It 



Wy 



2000-2500 m. 



SIDERANTHUS Fraser 



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

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

 Sideranthus integrif otitis Fraser and 5. pinnatifidus Fraser as syno- 

 nyms of Amellus villosus and A. spinulosits described on page 564. 

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

 the type of Sideranthus. Amelias villosus with its relatives was 

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

 1824, according to different interpretations, long before Eriocarpum 

 was established (1840). This leaves Sideranthus pinnatifidus as 

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

 the real author of Fraser* s Catalogue, made Sideranthus a subgenus 

 of Dicteria containing the only species D. spinulosa (Aplopappus 

 spinulosits DC. See Trans. Am. Phil. Soc. II. 7 : 301) ; and thus 

 shows that he regarded it as the type of Sideranthus * 



Leaves spinescent toothed, not pinnatifid. 



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



Heads radiate ; annual. 

 Leaves pinnatifid. 



2. S. rubiginosus 



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



Plant cinereous pubescent, more or less glandular. 3. S. aastralis. 



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



Plant neither floccose nor cinereous. 



Plant perfectly glabrous or sparingly glandular puberulent. 



5. S. glaberrimus 



Plant finely puberulent. 



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



Heads somewhat turbinate ; bracts densely glandular puberulent. 



7. 5. tiirbinellus. 



1 i. Sideranthus grindelioides (Nutt.) Britton 



Eriocarpum grindelioides Nutt. Trans. Am. Phil. Soc. II. 7 

 321. 1840. 



Aplopappus Nuttall ii Torr. & Gray, Fl. N. A. 2 : 240. 184 2 



* Professor Greene (Pittonia 2 : 115) seems to think Sideranthus is derived from 

 the Latin sidm % star, and the Greek, avdoq, flower. It is better to regard the first par 

 also as Greek, ohh'/poc, iron. Why accuse Nuttall of making a hybrid word, whic 

 we would not permit ourselves ? 



