1210 



CARDUACEAE 



Stem and branches with appressed pubescence : leaves 



nearly glabrous. 76. A. multiflorus. 



Stem and branches with spreading pubescence : leaves 



manifestly pubescent and ciliate. 77. A. exiguus. 



Bracts acute or merely obtusish. 

 Racemes or panicles secund. 



Cauline leaves linear to linear-lanceolate, minutely 



hack-toothed. 



Plants sparsely branched, and with few heads. 78. A. racemosut. 

 Plants profusely branched, heads very numerous. 79. A. vimineus. 

 Cauline leaves oblong or lanceolate, dentate or ser- 

 rulate. 

 Stem and branches sparingly pubescent or gla- 



brate. 80. A. laterifloruit. 



Stem and branches villous ; as also the midrib 



beneath. 81. A. hirsuticaulis. 



Racemes or panicles not definitely one-sided. 



Cauline leavesoval. 82. A. spatettiformin. 



Cauline leaves narrow. 



Oauline leaves entire, somewhat linear or linear- 

 lanceolate. 



Heads white (sometimes becoming purplish). 



Heads numerous, 8-14 mm. broad : leaves 



of the upper parts of the stem and 



branches subulate. 83. A. ericoides. 



Heads more scattered, 12-18 mm. broad : 



upper cauline leaves linear. 

 Branches divaricate, rigid, prolonged: 



rameals subulate. 84. A. juniperinus. 



Branches often upturned or subcorym- 



bose : many rameals flat, linear. 85. A. Paxoni. 



Heads chiefly colored,. 



Rays crimson or pink. 86. A. Priceae. 



Rays violet. 



Leaves rough-pubescent all over, above. 87. A. Baldwinii. 

 Leaves smooth and glabrous, except the 



margins. 63. A. elodes. 



Cauline leaves serrate. Longifolial Asters, Nos. 



88-92. 

 Heads mostly less than 16 mm. broad. 



Heads abundant, closely panicled. 88. A. Tradescanti. 



Heads remotely panicled or sparse. 89. A, agrostifolius. 



Heads mostly over 16 mm. broad. 



Rays usually white : leaves scarcely firm. 



Leaves smoothish, elongated. 90. A. paniculatus. 



Leaves and stem minutely pubescent. 91. A. MissouriensiK. 

 Rays usually bluish violet. 



Leaves firm, rough or roughish. chiefly 

 hack-serrate, the margins not 

 thickened. 92. A. salidjolius. 



Leaves with thickened and scabrous 

 margins, but smooth and glabrous 

 elsewhere. 62. A. Novi-Belgii. 



ft Heads numerous, in a terminal umbel-like corymb. Mis- 



cellaneous Asters, Nos. 93-102, begin here. 

 Leaves typically linear, entire or nearly so : bracts linear- 

 oblong, obtuse. 93. A. ptarmicoides. 

 Leaves typically oblong-acuminate to elliptic, coarsely 



toothed : bracts linear-subulate. 94. A. acuminates. 



Basal and lower cauline leaves grass-like. 



Leaf-blades entire. 95. A.paludosus. 



Leaf-blades with few or several spinuliform teeth. 



Heads sessile and subremote in the upper axils. 96. A. spiniilosut. 



Heads terminal, solitary or clustered. 97. A. eryngiifolius. 



** Leaves fleshy or succulent : plants sometimes armed with spines. ' 

 Stem solitary, its base not woody :' plant unarmed. 



Plants perennial from a caudex or rootstock : heads mostly over 12 



mm. wide. 



Leaves chiefly basal and linear, long-petioled. 98. A. Chapmani. 



Leaves scattered, linear and sessile. 99. A. tenuifolius. 



Plants annual : heads mostly less than 10 mm. wide. 



Involucre campanulate : rays fewer than the disk-flowers. 100. A. ezili*. 



Involucre cylindraceous : rays more numerous than the disk- 

 flowers. 101. A. subnlatus. 

 Stems several from the woody persistent base : plant spine-armed. 102. A. spinosus. 



1. Aster divaricatus L. Stems tufted, 4-6 dm. tall, assurgent, flexuous, brittle, 

 terete, glabrate at maturity : leaf-blades thin, smoothish, slender-petioled, ovate-lanceolate, 

 closely and saliently dentate with sharp teeth, incurved-acuminate, the basal sinus moder- 

 ately large, broad and deep : leaves of the inflorescence (bracteah] typically small, sessile, 

 short, ovate-acute to short-oval, nearly entire : corymb broad, flattish, repeatedly and 

 widely forked, the slender branches long, divergent : heads 18-25 mm. broad : ray-flowers 

 chiefly 6-9 ; ligules white, or rarely roseate or slightly crimson : young involucre short-cyl- 



