DiPLOPAPPUs. COMPOSITiE. 181 



imbricated, lanceolate or subulate, 1-nerved or carinate, destitute of herba- 

 ceous or squarrose tips. Receptacle flat, somewhat alveolate ; the alveoli 

 toothed. Appendages of the style subulate or lanceolate, rarely short. Ache- 

 nia more or less compressed. Pappus double ; the exterior of copious sca- 

 brous often unequal capillary bristles, as long as the corolla ; the exterior 

 very short, setulose, or setaceous-subulate. — Perennial (chiefly American) 

 herbs or suffruticose plants, somewhat variable in habit ; with alternate most- 

 ly entire and sessile leaves. Heads corymbose, or terminating the simple 

 branches. Rays blue, purple, or white ; the corolla of the disk yellow, rarely 

 changing to purplish. 



The name Diplostephium appertains to the section which comprises the original 

 species, D. lavandulaefolium, Kmith; which ajjpears to differ considerably, and per- 

 haps generically from the Eudiplostephium of De Candolle, and is perhaps much 

 nearer tlie Diplopappus § Amelloidei of the latter author. — In a note under Aster § Or- 

 thomeris, we have already observed that some, if not all of the species of De Can- 

 doUe's Diplopappus § Cahmeridei, with the Aster peduncularis, Wall. (Amphiraphis 

 peduncularis, DC), the Calimeris flexuosa, Lindl.&cc. (all natives of the mountains 

 of India), appear to form a well-marked genus. 



§ 1. Bristles of the inner imirpus similar, not clavellate or thickened at the 

 apex ; the exterior setulose : achenia villous or silky, short, someivhat com- 

 pressed : involucre about the length of the disk : leaves crowded, linear, 

 risid, 1-nerved, mucronulate, with serrulate-ciliate very scabrous margins : 

 heads terminating the simple branches : rays violet. — Ian the. (Diplo- 

 stephium § Amelloidea, Nees. Diplopappus § Amelloidei, DC.) 



1. D. linariifolius (Hook.) : stems strict, puberulent or slightly scabrous, 

 usually several from the same root or suffrutescent base ; leaves rigid, mostly- 

 spreading, linear, mucronulate, strongly 1-nerved, glabrous, with very scab- 

 rous serrulate-ciliate margins ; scales of the turbinate-campanulate involucre 

 imbricated in several series, rigid, carinately 1-nerved, at length somewhat 

 spreading ; the exterior short, lanceolate-subulate ; the innermost linear, 

 mostly obtuse; exterior pappus copious, setaceous; achenia narrow, silky- 

 MiWoua.— Hook. ! Ji. Bor.-Am. 2. p. 21 ; Darlingt. ! fl. Cest. p. 473. D. 

 linariifolius & D. rigidus, Lindl. ! in DC. ptrodr. 5. p. 277. Diplostephium 

 linariifolium, Nees, Ast. p. 199. Chrysopsis linariifolia, Nutt. ! gen. 2. p. 

 152. Aster linariifolius, Linn.! spec. 2. p. 874; Michx. ! fl. 2. p. 110; 

 Pursh, fl. 2. p. 545 ; Ell. ! sk. 2. p. 365. A. rigidus, Linn. I. c. (fide pi. 

 Gronov. .') ; Michx.! I. c. ; Pursh! fl. 2. p. 544. (excl. syn. A. nemoralis, 

 Willd.) A. pulcherrimus, Lodd. bot. cab. 1. t. 6. A. Americanus frutes- 

 cens, &c. Pluk. aim. t. 14, /. 7. 



Dry soil, throughout the United States ! also in Canada ! and New- 

 foundland, Mr. Cormack ! (in herb. Hook.) Sept.-Oct. — Stems 8-20 inches 

 high, simple and terminated by a single head ; or with few or numerous, 

 simple, leafy, corymbose, clustered, or somewhat racemose branches. Leavea 

 near the root short and scale-Uke, appressed, obtuse, 1-3-nerved, rigidly cili- 

 ate; the other cauline ones about an inch long, very numerous, mostly 

 spreading or recurved, shining above, pale and with the midrib prominent 

 beneath, veinless ; those of the somewhat hoary branches much smaller, 

 the uppermost subulate. Heads rather large ; the numerous scales of the 

 involucre somewhat ciliate ; the inner often with purplish tips. Rays 10-12, 



elongated, showy. Appendages of the style attenuate-subulate, hairy "We 



know not how the D. rigidus, Lindl. S^v. is to be distinguished, even as a 



