160 COMPOSITtE. Aster. 



***** Scales of the somewhat hemispJierical involucre closely imbricated in 3-4 un- 

 equal series, shorter than the disk, oblong, obtuse ; the exterior somewhat carinate, pass- 

 ing into subulate bracts ; the interior with broad membranaceoiis margins : alveoli of 

 the receptacle entire : appendages of the style lanceolate : achenia oblong, very gla- 

 brous : pappus copious, as long as the corolla, unequal ; the longer bristles claveliate- 

 thickened at the apex : stems simple : leaves linear-lanceolate, rigid, scabrous : heads 

 (rather smaW) corymbose. (Species of Heleastrum, DC) 



117. A. ptarmicoides : stems several from a somewhat woody rhizoma, 

 scabrous above ; leaves linear-lanceolate, acute, somewhat shining, smooth 

 or scabrous, with very scabrous margins, entire ; the lower elongated, often 

 slightly and remotely toothed, tapering to the base or somewhat petioled ; 

 corymb fastigiate, simple or compound ; scales of the involucre rather obtuse ; 

 rays 12-18, linear-oblong, short. — Chrysopsis alba, iVw?<. / gen. 2. p. 152. 

 Doellingeria ptarmicoides, Nees, Ast. p. 183. Diplopappus albus. Hook. ! 

 fl. Bor.-Am. 2. p. 21; Gray! in ann. lye. NewYorJc, 3. p. 226. D. ptar- 

 micoides, Lindl. ! in kerb. Torr., Sfc. Heleastrum album, DC. prodr. 5. 

 p). 264, excl. syn. Aster albus, Willd. 1 Bucephalus albus, Nutt.! in trans. 

 Amer. phil. soc. (n. ser.) 7. p. 299. 



/i. heads few or solitary. (Lindl. ! in DC. I. c.) 



y. leaves nearly all furnished with 3 or 4 sharp spreading teeth on each 

 side ; stem very scabrous above ; inner scales of the involucre rather broad- 

 er. — Heleastrum album y. DC. I. c. [Lindl..') 



Dry soil, or rocky banks of streams, from the Missouri, near Fort Man- 

 dan! to Saskatchawan ! Lake Superior! Wisconsin! Michigan! Upper 

 Canada along the Great Lakes ! to the banks of Black River, Jefferson 

 County, New York! and Pownal, Vermont, Mr. Rabbins ! — July-Sept. — 

 Stems 6-18 inches high, rigid, leafy, scabrous, especially above, with a minute 

 somewhat strigose pubescence. Leaves rigid, with serrulate-scabrous mar- 

 gins, or often sparsely ciliate towards the base, with a strong midrib and two 

 more or less distinct lateral nerves, anastomozing towards the summit ; the 

 radical and lowermost 3 to 6 inches long, 3-4 lines wide, linear-lanceolate, 

 or oblanceolate, tapering gradually into a more or less distinct petiole ; the 

 upper successively shorter and less narrowed at the base ; those of the 

 branches scattered, linear-subulate. Corymb spreading. Involucre nearly 

 glabrous, greenish ; the outermost scales somewhat lanceolate-subulate ; the 

 inner more membranaceous, narrowly oblong, slightly ciliate, shorter than 

 the disk. Rays pure white. Pappus soft, white. — It is not probable tliat 

 this is the Aster albus, Willd. herb. ^' Spreng., a species of unknown origin, 

 which is said to have oblong-lanceolate, rather obtuse and nerveless leaves, 

 leafy branches, and elongated rays. — This plant has little agreement with 

 De Candolle's Heleastrum paludosum, besides the clavellate pappus; a 

 character which equally exists in some other divisions of Aster, in a few spe- 

 cies of Galatella, &c. 



118. A. lutescens: pubescent-scabrous throughout; leaves lanceolate, acute, 

 scarcely nerved ; the lower elongated and tapering into a petiole, somewhat 

 serrulate ; the upper short, oblong-linear ; corymb simple or rather com- 

 pound ; scales of the involucre oval or oblong, very obtuse, minutely pubes- 

 cent ; rays ochroleucous ? — Diplopappus lutescens, Lindl..' in DC. prodr. 

 5. p. 278. D. albus /?. lutescens. Hook. ! fl. Bor.-Am. 2. p. 21. 



Saskatchawan, on dry elevated grounds of the Assiniboin River, Douglas! 

 — Plant with the habit of the preceding (a foot high), everywhere covered 

 with a similar, but denser, rough pubescence. Lower leaves 5-6 inches long, 

 5 lines wide ; both surfaces scabrous-pubescent, and not shining : the upper 

 cauline an inch or less in length, and broader in proportion. The involucre 

 is as long as the disk (but the flowers are not fully developed, so that this 



