118 COMPOSITE. Aster. 



serrulate-scabrous ; those of the branches and branchlets gradually reduced 

 to subulate bracts resembling the exterior scales of the involucre. Rays 

 about 20, elongated, blue or purple ? Disk about 20-flowered. Achenia 

 glabrous to the naked eye, but clothed with a very minute appressed pubes- 

 cence under a lens. Pappus reddish-brown, not exceeding the innermost 

 scales of the involucre. — A very distinct species, remarkable for its exactly 

 turbinate involucre (5-6 lines long), which is very acute at the base, owing 

 to the short exterior scales : these are coriaceous and white, with very short 

 greenish tips. 



* ;^ % « % 4= * Heads (^middle-sized or small^ paniculate or racemose : scales of tlie 

 ohovoid or campanidate involucre imbricated in several series (the exterior successively 

 shorter'), commonly oppressed, chartaceous or somewhai membranaceous, vnth short 

 green tips : achenia glabrous or slightly pubescent : radical and lowest cauline leaves 

 (large) cordate, with elongated naked or margi?i£d petioles ; the upper often petioled. — 

 Heterophylli, Nees. 



+ Leaves entire, undulate, or slightly serrate : heads loosely paniculate or race- 

 mose : rays usually bright blue or violet. 



27. A. azureus (Lindl.) : stem somewhat scabrous, racemose-compound 

 at the summit ; the branches slender and rigid ; leaves scabrous ; the radical 

 and lowest cauline ovate-lanceolate or ovate-oblong, cordate, somewhat 

 serrate, on long (naked or margined) often hairy petioles ; the others lan- 

 ceolate or linear, acute at each end, sessile, mostly entire ; those of the 

 spreading branches subulate, mostly very numerous and appressed ; in- 

 volucre broadly obconlc, nearly the length of the disk; the scales closely 

 imbricated, narrowly-oblong or linear, abruptly acute ; achenia glabrous or 

 very slightly and sparsely hairy. — Lindl. ! in Hook, compan. to hot. mag. 1. 

 p. 98, 8^' in DC. jJrodr. 5. p. 244. A. Oolentangiensis, Riddell ! synops. 

 fi. Western States, ^;. 55. 



Woods and prairies, of theWestern States ; from Western Louisiana, Dr. 

 Leavenworth! Dr. Hale ! Missouri, Dru7n7nond .' Makato River (a tributary 

 of St. Peter's), Mr. Nicollet! to Ohio, Dr. Riddell! Dr. Paddock! Dr. 

 Van Cleve ! and Fort Gratiot, Michigan, Dr. Pitcher ! Also Georgia, Dr. 

 Chapman! (a variety with more lax branches.) Aug.-Oct. — Stem 1-3 feet 

 high, rigid. Heads equalling or sometimes exceeding those of A. undulatus 

 in size ; the involucre between hemispherical and turbinate, nearly as broad 

 as long, and rather shorter than the pappus ; the scales numerous, appressed, 

 white except the green rhombic or triangular tips, slightly pubescent. Rays 

 blue. — A well-marked species (" appearing as if a hybrid between A. 

 rubricaulis and A. multiflorus," Lindl., who described from imperfect spe- 

 cimens, wanting tVie lower leaves), manifestly connecting this group with 

 the foregoing, with which it exactly accords in its involucre &c., remarkable 

 for its scabrous leaves; the lower 3-5 inches long (sometimes hairy beneath) ; 

 those of the branchlets reduced to short subulate bracts. The inflorescence 

 usually consists of a few racemose rigid (although slender) branches, some- 

 what paniculate at the summit of the stem ; but in some large specimens 

 from Dr. Leavenworth, the stem is much racemose-compound, the rigid 

 primary branches often more than a foot in length ; and these, with the race- 

 mose branchlets, all terminated by single heads and clothed with uniform 

 very short subulate leaves, so different from those of the stem, present a very 

 marked appearance. 



28. A. Shortii (Hook.) : stem slender, nearly glabrous, racemose-panicu- 

 late at the summit ; leaves glabrous and nearly smooth above, minutely 

 pubescent beneath, lanceolate or ovate-lanceolate, tapering to a sharp point ; 

 the radical and cauline ones all more or less cordate and on naked (some- 



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