X 



Studies on the Rocky Mountain Flora.— I 



By P. A. Rydberg 



SOME SMALLER GENERA OF COMPOSITES 



STENOTUS Nutt. 



This genus was established by Nuttall in 1840. It was re- 

 tained as a genus by Torrey and Gray in their Flora, but merged 

 with several others into Aplopappus by Gray in his Synoptical 

 Flora. A few years ago (1894), Professor Greene reestablished 

 the genus, removing from it, however, a member erroneously placed 

 in the genus by Torrey and Gray, viz., Stenotus pygmaeus Torrey 

 and Gray {Aplopappus pygmaeus Gray), which he referred \.o Macro- 

 nema* If such a transfer was the very best is questionable, for 

 that species is as much a stranger in Macronema as it is in Stenotus. 

 It has the outer bracts foliaceous and the style-appendages long 

 and attenuated which are characters found in Macronema ; but the 

 habit is very unlike Macronema and the outer foliaceous bracts are 

 numerous as in Pyrrocoma. I had some transient thought of trans- 

 ferring it to that genus ; but the; purely white pappus, the densely 

 cespitose habit, and the lack of the thick taproot, debar it from 

 Pyrrocoma. These characters ally it to Solidago ; but the differ- 

 ence in structure of the outer and the inner bracts makes it un- 

 natural to place it there as well. It is very hard to decide which 

 would be the best course to take, either to place it as an anoma- 

 lous member of one of these genera or to make it the type of a new- 

 genus. Perhaps some other and better relationship may be found. 



Of the other species included in Aplopappus § Stenotus by 

 Gray, A. Panyi is, I think, rightly referred to Solidago. A. Lyalln 

 was altogether omitted by Professor Greene, when he made the 

 segregation in Pittonia. He may have overlooked this, but it is 

 more probable that he omitted it, because he did not know where 

 to place it. The relationship is without any doubt closest with 

 Solidago, notwithstanding the solitary head. 



* In a recent distribution of plants from Colorado determined by Professor Greene, 

 'his was distributed under its original name Stenotus pygmaeus. 



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