COMPOSITAE. 949 



* * Rays mostly white or nearly so (often pink or purple in Nos. 59, 61 , 63, 64, and 73). 



Heads corymbose, 20-40 mm. broad. 

 Leaves ovate-oblong, acuminate, sharply serrate ; bracts linear-subulate. 



59. A. acuminatus. 

 Leaves linear, entire or nearly so; bracts oblong, obtuse. 60. A. ptarmicoides. 



Heads solitary at the ends of slender branchlets. 



Leaves linear or linear-lanceolate, acute or obtuse. 61. A, dumosus. 



Leaves oblong-lanceolate, acuminate at both ends. 62. A. Gravesii. 



Heads paniculate, or racemose, 8-20 mm. broad 

 f Bracts of the involucre acute to obtusish; plants glabrous or pubescent. 



(a) Heads paniculate, not in i-sided racemes. 

 Stem leaves lanceolate, serrate or entire. 

 Heads 16-20 mm. broad. 



Plants glabrous, or sparingly pubescent above. 



Leaves firm, roughish or rough; rays often bluish. 63. A. salicifolius. 

 Leaves thin, smoothish; rays chiefly white. 64. A. paniculatus. 



Plant puberulent all over. 65. A. Missouriensis. 



Heads 12-16 mm. broad; stem-leaves narrowly lanceolate. 66. A. Tradescanti. 

 Stem-leaves linear-lanceolate to subulate, mostly entire. 



Heads scattered, 12-18 mm. broad ; upper leaves linear. 67. A. Faxoni. 



Heads numerous, 8-14 mm. broad; upper leaves subulate. 



Paniculately branched, bushy. 68. A. t,ricoides. 



Simple, or with ascending slender branches; northern. 69. A. Pringlei, 



(b) Heads racemose and i-sided on the branches. 

 Stem-leaves oval, oblong, or lanceolate, serrate, or chiefly so. 



Stem pubescent or glabrate. 70. A. lateriflorus. 



Stem villous; leaves narrowly lanceolate, thin. 71. A. hirsuticaulis. 



Stem-leaves linear-lanceolate to linear, nearly entire ; stem glabrate. 



72. A. vimineus. 



\ f Bracts of the involucre, at least the outer, obtuse; plants very rough. 

 Heads 6-8 mm. broad, very numerous, densely clustered. 



Pubescence appressed; leaves nearly glabrous. 73. A. multiflorus. 



Pubescence spreading; leaves pubescent and ciliate. 74. A, exiguus. 



Heads 12-16 mm. broad, rather loosely clustered ; western. 75. A. commutatus. 



D. Leaves fleshy, narrow, entire ; plants of salt marshes or saline soil (No. 77 some- 

 times in non-saline situations). 



Perennial; heads 12-25 mm - broad; involucral bracts lanceolate, acuminate. 



76. A. tenutfolius. 

 Annuals ; heads 6-10 mm. broad ; involucral bracts linear-subulate. 



Involucre campanulate; disk-flowers more numerous than the rays; rays about 4 mm. 



long. 77. A. exilis. 



Involucre cylindraceous; disk-flowers fewer than the very short rays. 



78. A. subulatus. 



1. Aster carmesinus Burgess. CRIMSON-DISK ASTER. (I. F. .3735.) Stems 

 erect, delicate, 3-6 dm. high, glabrous, reddish brown, terete. Leaves all peti- 

 oled, glabrate, very thin, but firm and crisp, the lower and basal ones somewhat 

 oval, rounded into a small deep sinus at the base, bluntly acute or short-acuminate 

 at the apex, crenate-serrate, the upper ones sometimes ovate-lanceolate, the upper- 

 most short-elliptic; petioles slender ; inflorescence 12.5 cm. broad, or less ; rays 

 chiefly 6, white ; disk at first golden yellow, finally deep purplish crimson; florets 

 broadly bell-shaped; outer bracts obtuse, ciliate, pale, with a green tip. On shaded 

 rocks in the lower Hudson valley. Sept. 



2. Aster divaricatus L. WHITE WOOD ASTER. (I. F. f. 3737.) Sterns 

 tufted, assurgent, flexuous, brittle, terete, 4-6 dm. high, glabrate at maturity. 

 Leaves thin, smoothish, slender-petioled, ovate, lanceolate, closely dentate with 

 sharp teeth, or the small basal ones coarsely serrate, acute to acuminate, the basal 

 sinus moderate; leaves of the inflorescence small, short, ovate and acute to orbicu- 

 lar, subentire; corymb broad, flattish, repeatedly forked, the slender branches 

 long, divergent ; heads 18-25 mni - broad; rays chiefly 6-9, white; disk turning 

 reddish brown; bracts of the involucre broad, ciliate, the rounded tip with an in- 

 conspicuous green spot. In open woodlands and thickets, in rather dry soil, 

 Canada to Man., Ga. and Tenn. Variable; rays rarely rose-purple. Sept.-Oct. 



Aster divaricitus cymu!6sus Burgess. Smaller, bearing a single dense corymb about 

 I dm. broad, or several smaller ones ; the branches short, suberect; rays short, broad, 



