1210 



CARDUACEAE 



Stem and branches with appressed pubescence : leaves 



nearly glabrous. 

 Stem and branches with spreading pubescence : leaves 

 manifestly pubescent and ciliate. 

 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. 

 Plants profusely branched, heads very numerous. 

 Cauline leaves oblong or lanceolate, dentate or ser- 

 rulate. 

 Stem and branches sparingly pubescent or gla- 



brate. 

 Stem and branches villous ; as also the midrib 

 beneath. 

 Racemes or panicles not definitely one-sided. 

 Cauline leaves oval. 

 Cauline leaves narrow. 



('auline 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. 

 Heads more scattered, 12-18 mm. broad: 

 upper cauline leaves linear. 

 Branches divaricate, rigid, prolonged : 



rameals subulate. 

 Branches often upturned or subcorym- 

 bose : many rameals flat, linear. 

 ' Heads chiefly colored. 



Rays crimson or pink. 

 Rays violet. 



Leaves rough-pubescent all over, above. 

 Leaves smooth and glabrous, except the 

 margins. 

 Cauline leaves serrate. Longifolial Asters, Nos. 

 88-92. 

 Heads mostly less than 16 mm. broad. 

 Heads abundant, closely panicled. 

 Heads remotely panicled or sparse. 

 Heads mostly over 16 mm. broad. 



Rays usually white : leaves scarcely firm. 

 Leaves smoothish. elongated. 

 Leaves and stem minutely pubescent. 

 Rays usually bluish violet. 



Leaves firm, rough or roughish. chiefly 

 hack-serrate, the margins not 

 thickened. 

 Leaves with thickened and scabrous 

 margins, but smooth and glabrous 

 elsewhere, 

 tt Heads numerous, in a terminal umbel-like corymb.— Jfi's- 

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

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

 oblong, obtuse. 

 Leaves typically oblong-acuminate to elliptic, coarsely 

 toothed : bracts linear-subulate. 

 Basal and lower cauline leaves grass-like. 

 Leaf-blades entire. 



Leaf-blades with few or several spinuliform teeth. 

 Heads sessile and subremote in the upper axils. 

 Heads terminal, solitary or clustered. 

 ** 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. 

 Leaves scattered, linear and sessile. 

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



Involucre campanulate: rays fewer than the disk-flowers. 

 Involucre cylindraceous : rays more numerous than the disk- 

 flowers." 

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



76. A. multiflorus. 



77. A. exiguus. 



78. A. racemosua. 



79. A. viminexis. 



80. A. lateriflonat. 



81. ^. hirsuticaulis. 



82. A. spatelliformis. 



83. A. cricoides. 



84. A. juniperinus. 



85. A. Faxoni. 



86. A. Priceae. 



87. A. Baldwinii. 

 63. ^. elodes. 



88. A.Tradescanti. 



89. A. agrostifolius. 



90. A. paniculatiis. 



91. A. Missotiriensiit. 



92. A. salicifolius. 

 62. A. Xovi-Belgii. 



93. A. pfannicoides. 



94. A. acuminatus. 



95. A. paludosus. 



96. A. spiiudosuB. 



97. A. eryngiifolixis. 



98. A. Chapmani. 



99. A. tenuif alius. 



100. A. exilU. 



101. A. siLlxdatus. 



102. A. spinosuit. 



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

 terete, glahrate 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 (bmcteals) 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- 



