G35 RvDBERG : Studies on the Rocky Mountain Flora 



ing the corolla-tube, but often shorter, yet never hidden by the 

 hairs of the achenes. 



This species has been confused with H. filifolius and H. fiaves- 

 ccns. Baker, Earle & Tracy's specimens were determined as the 

 latter by Professor Greene. The species is, however, much nearer 

 related to H . filifolius , from which it differs mainly in the lower 

 habit and the longer scales of the pappus. These characters, to- 

 gether with the longer lobes of the leaves distinguish it from //. 

 litteus. It grows on dry hills, at an altitude of i 500-3000 m, 



Colorado: Walsenburg, 1900, Rydbcrg & Vreeland, S479 

 (type); Mesas near Pueblo, 5^77; Cuchara Valley, 5^76"; Du- 

 rango, 1898, Baker, Earle & Tracy, 1028 ; Garden of the Gods, 

 near Pikes Peak, 1895, E. A. Bessey. 



6. Hymenopappus filifolius Hook. Fl. Bor. Am. i : 317. 1833 



This species is common on plains and prairies to an altitude of 

 2000 m., and ranges from Saskatchewan and Montana to Colorado 

 and Nebraska. 



7. Hymenopappus luteus Nutt. Trans. Am. Phil. Soc. (H.) 7: 



374. 1 841 



Dr. Gray in his Synoptical Flora referred this species to H. 

 filifolius, which, however, does not fit Nuttall's description. Many 

 years before he had named Fendler's specimens H. luteus. These 

 agree fairly well with Nuttall's description, except as to the pap- 

 pus, which in them is much more prominent than in any of the 

 other species. Nuttall states that the scales of the pappus of H. 

 luteiis are very short and hidden by the hairs of the achenes. 



In 1897 Prof. Aven Nelson collected a Hymenopappus on 

 Green River, which he intended to describe as new, especially as 

 the type specimen was without pappus. A closer examination re- 

 vealed, however, that some of the specimens really had some 

 small scales. These agreed perfectly with Nuttall's description. 

 Nelson's specimens and my own, collected two years before, also 

 on Green River, are the only ones that perfectly agree with Nut- 

 tall's description of H. luteus. His type was collected on tiie 

 Ham's Fork of the Colorado of the West. What the present 

 name of Ham's Fork is or its exact location I have been unable 



