OF ARTS AND SCIENCES. 63 



S. viRGATA, Benth. Bot. Sulpli. 42. S. paniculata, chiefly, Eaton, 

 Bot. King Exp. 1. c. ; Gray, Bot. Calif. 428. S. elata, Nutt. PI. 

 Gamb. 173? Quite distinct from the following species, with which I 

 had confounded it. The heads sometimes bear 6 or 8 flowers, or even 

 10 as it would seem, but commonly only 5. The akenes of the two 

 species are similarly subclavate-oblong and rugose-tuberculate between 

 the narrow ribs. 



•H- -H- Pappus sordid or fuscous ; its bristles rather short-plumose 

 down nearly or quite to the more or less paleaceous-dilated or squa- 

 melliferous base : heads 3— 5-flowered, narrow, in a narrow open 

 panicle. 



S. PANicuLATA, Nutt. ; Torr. & Gray, Fl. ii. 743. Of more north- 

 ern range than the preceding. Pappus inclined to form phalanges. 



++ -H- -w- Pappus white or whitish ; its bristles plumose above but 

 naked below the middle ; base more or less dilated or paleaceous, or 

 with lateral setulose teeth or squamella? : heads paniculate, on 

 squamulose jieduncles : akenes tuberculate-rugose at maturity. 



= Pappus-bristles 9 to 18, with dilated bases not rarely connate into 



4 or 5 phalanges. 



S. EXiGCA, Nutt. 1. c. HeiniptiUum Bigelovii, Gray, Bot. Mex? 

 Bound. 105. These two names were founded on extreme forms ; 

 NuttalFs upon exceedingly attenuate branches of an apparently de- 

 pauperate plant, with very narrow 3-5-flowered heads. The latter 

 name, upon the ordinary form with more robust stem, often 2 feet 

 higli, in no sense exiguous, the heads bearing 5 or rarely G to 8 

 flowers in an involucre of 4 or 5 lines in length. It is a species of 

 wide range, mainly Southern. 



= = Pappus-bristles 5 or sometimes 7, distinct, slender, dilated only 

 at the very base, plumose only above the middle. 



S. PENTACH^TA, Eatou, 1. c. Known only in W. Nevada ( Watson, 

 Shockley) as a low plant, and upon the edge of the desert in S. E. 

 California, where Parish found a large form, 2 or 3 feet high. 



§ 3. Hemiptilium, Gray, in part. Heads 5-flowered, small : pappus 

 of 4 to 6 rigid palece rather than awns, ciliate-plumose only toward 

 the summit. 



S. ScHOTTii, Gray, Bot. Calif, i. 427. Hemiptilium Schottii, Gray, 

 Bot. Mex. Bound. 105. Found only by Schott, many years ago, on 

 the Gila River. 



