CARDUACEAE 1215 



spiciform and beset with small remotish subsessile heads : stem 8 dm. high or less : leaf- 

 blades thick and heavy, somewhat canescent, hispid above, velvety-hispidulous below ; leaf- 

 form elongated triangular ; the truncate base slightly rounded at the corners, and sometimes 

 a little subcordate ; leaf-blades .3x1 cm. or more, acute or obtusish, the sides straight, ser- 

 rate or crenate ; petiole short, forming a narrow cuneate wing : rameals stiff, very numer- 

 ous, overlapping and appressed, linear-elliptic : heads small, hardly 2 cm. broad : bracts 

 linear-acute, the green tip lanceolate. Kesembles A. hirteUus ; but has the predominant 

 leaves thick, triangular: stems more smooth, flagellate spiciform ; branches more frequent : 

 rameals appressed, narrower and closer, and the green tips of the bracts much broader. 

 Eepeatedly collected for A. undukiius, A. azureus, A. Baldwinii, A. Drummondii, and A. 

 sagittij'ohus. 



On plains and prairies, Alabama to Kansas and Texas. Fall. 



25. Aster azureus Lindl. Stem 3-12 dm. high, slender, stiff, rough, with numerous 

 ascending or patent branches : leaf-blades thick, of a peculiar crusty texture when dry, sca- 

 brous on both sides, those of the basal and lower cauline leaves cordate, ovate to oblong-lan- 

 ceolate in type, shallow-serrate, usually acute, 5-15 cm. long, with slender often pubescent 

 petioles ; those of the upper cauline leaves with short petiole-like bases or sessile, lanceolate 

 or linear, entire ; those of the branches reduced to small appressed scales : heads numerous, 

 20-25 mm. broad : involucre turbinate ; bracts glabrous, linear-oblong, abruptly acute, 

 imbricated, their broad sharp green tips appressed : ray-flowers 10-20 ; ligules bright blue, 

 6-8 mm. long : pappus tawny. Kesembles A. undulatus L. ; but leaves hispidulous on both 

 surfaces ; flowers smaller ; rays darker and bluer ; pubescence scanty. 



On prairies and along borders of woods, New York to Minnesota, Georgia, Kansas and Texas. 

 Summer and fall. — A. azureus sccibrior Engelm. principal leaves with elliptical lanceolate entire long- 

 petioled non-cordate blades ; branches more erect ; stem extremely rough. Ontario and Minnesota 

 through Missouri to Louisiana. 



26. Aster capillaceus Burgess. Stem about 6 dm. high, terete, rough in parts, often 

 polished-smooth in others, sometimes manifestly pubescent : leaves much as in A. azureus, 

 but the blades thinner, less roughened, almost never cordated, bearing bristles which rise 

 each from a small papilla ; lower leaf-blades large and very long petioled, elliptic-lanceo- 

 late, coarsely crenate (in some small plants entire) ; others enlarged upward, oblong-spat- 

 ulate or linear-spatulate and entire ; upper cauline leaves linear-lanceolate ; axiles subu- 

 late ; radic^il leaves several, often four, their type broadly oval or oblong, obtuse or rounded 

 at base and apex, coarsely shallow-dentate, suggesting Erigeron annuus : inflorescence al- 

 most naked from lack of bracteals, the filiform pedicels therefore conspicuous : heads 

 somewhat remote, rather large, 2 cm. broad, blue-violet, with turbinate base : bracts broad, 

 abruptly triangular-pointed or cuspidate. Resembles A. azureus; but thinner, and less 

 roughened ; the heads fewer, larger, and their peduncles nude ; peculiar in its tendency to 

 develop Erigeroyi-Yike radicals and spatulate caulines. 



In dry grounds, Wisconsin and Illinois through Missouri to Texas. Late summer and fall. 



27. Aster vernalis (Engelm.) Burgess. Stem 4 dm. high, or more, densely race- 

 mosely branched : leaf-blades entire, of heavy firm texture, very rough, with close short 

 stout bristles abruptly papillose-thickened at the base ; the radical blades oblong-acumi- 

 nate, with a truncate square-shouldered base and slender petiole 7 cm. long or nearly as 

 long as the blade : caulines linear and grass-like, biacuminate, often with slender petioles 

 2 cm. long : inflorescence irregular, racemosely compound, elongated and narrow, its 

 branches not so long and straggling as in A. poaceus, not so fastigiate or scoparial as in A. 

 azureus: heads 0.5 cm. high, 1 cm. broad: bracts linear-acute or acuminate. Between A. 

 azureus and A. poaceus in leaf-form and inflorescence. \^A. azureus var. ? vernalis Engelm.] 



In open woods and on prairies west of Houston, Texas, Spring and summer. 



28. Aster poaceus Burgess. Stem diffusely and repeatedly much-branched, 8 dm. 

 high or less : leaves very rough and stiff", of grass-like form ; chief leaf-blades linear- 

 elongate or falcate, often 13 cm. long, 0.5 cm. in uniform breadth, usually also with a nar- 

 row-margined petiole of 2-5 cm., apt to be erect, and with stout papillose-based bristles ; 

 radicals oblong-elliptic, measuring 8x1 cm. or less : inflorescence irregular, on very long 

 and straggling branches, which are often for 1.5 to 3 dm. clothed with minute subulate sub- 

 appressed bractlets : heads small, little over 1 cm. broad : bracts linear, with long sharp tips. 

 Represents the extreme of attenuation among the kindred of A. azureus. 



On plains and prairies, Missouri to Alabama, Oklahoma and Texas. Summer and fall. 



29. Aster undulatus L. Stem stiff, 3-10 dm. high, closely rough-pubescent, divari- 

 cately branched above : leaf-blades usually thick, rough on both sides when dry, pubescent 

 beneath, dentate, undulate or entire, acute or acuminate, those of the radical leaves small, 

 orbicular to ovate, soft-downy ; the lower cauline leaves ovate, with cordate base, 5-12 cm. 

 long, the naked petioles expanding into a clasping base, at least in some leaves ; middle 



