CARDUACEAE 



1209 



Stem low : leaves rough : inflorescence broad. 

 Heads long-peduncled, somewhat remote. 

 Involucre turbinate. 



Bracts linear, acute, not woolly. 

 Bracts broad, scale-like, obtuse, canescent. 

 Involucre campanulate. 



Bracts broad, oblong ; tips spreading : branches divaricate. 

 Bracts narrow-linear ; branches diffuse. 

 Heads chiefly short-peduncled, subsecund. 

 Stem tall : leaves soft : inflorescence narrow, 

 b. Chief bracts thin, narrow, loosely appressed (at least the upper half 

 spreading): stem usually pubescent. 

 Leaf-blades entire. 



Heads under 2..5 cm. broad : leaf-blades but narrowly clasping. 

 Plant widely branched and divaricate : spreading hair abundant 



on young stenis. 

 Plant fastigiately branched, rougher, little pubescent. 

 Heads over 2. .5 cm. broad : leaf-blades broadly clasping. 

 , Leaves not greatly elongated, oblong, soft-pubescent: stem tall, 



erect. 

 Leaves various, not soft-pubescent. 



Stem extensively trailing or climbing : leaves short. 

 Stem erect, slender, profusely branched : leaves elongated. 

 Leaves strongly clasping. 

 Leaves slightly clasping. 



Stem rigid : leaves narrowly oblong-lanceolate. 

 Stem weak : leaves bayonet-like, narrowly linear. 

 Leaf-blades sharply serrate. 



Inflorescence irregularly congested or corymbed : pubescence often 

 scanty. 

 I'pper leaves little clasping: bract-tips linear-subulate. 

 Upper leaves sheathing the axils : bract-tips deltoid. 

 Inflorescence broadly panicled, diffuse, leafy : heads somewhat remote. 

 Leaves with nearly straight sides, little constricted below. 

 Tubercular-based hair scattered over the stem. 

 No tubercular-based hair. 

 Leaves contracted into a broad petiolar portion : hair present in 

 lines on the upper stem. 

 Blades of the cauline leaves clasping, etc. Amplexicaul Astern, Nos. 41-63. 

 Blades of the cauline leaves merely sessile or essentially so, Nos. 64-102. 

 * Leaves not succulent or fleshy": plants not spiny-armed. 

 Basal and lower cauline leaves not grass-like, Nos. 64-95. 



Leaves silky or canescent on both sides, entire or nearly so, short. 

 Brevi/oiial Astert:, Nos. 64-69. 

 Heads corymbose-paniculate : outer bracts of the involucre oblong, 

 ovate-lanceolate or lanceolate: acbenes glabrous. 

 Leaves silky : outer bracts of the involucre canescent-silky. 

 Leaves canescent : outer bracts hirsute. 

 Heads racemed : bracts linear : achenes pubescent. 

 Leaves glabrous or pubescent, but neither silky or canescent. 

 Rays typically purple, blue, pink or violet. 



Tips of the iuvolucral bracts spreading or recurved. 

 Leaves relatively small and very numerous. 



Leaves erect and adnate to the stem and its branches. 

 Leaves more or less reflexed, not adnate to the stem. 

 Heads small, few : bracts but slightly spreading. 

 Heads large : bracts squarrose, glandular. 

 Leaves relatively large and few. 



Upper cauline leaves broad, chiefly ovate. 

 Upper cauline leaves narrow, narrow-oblong, varying to 

 oblanceolate, lanceolate or linear ; section Callias- 

 trum T. cfe G., Nos. 70-73. 

 Involucre hemispheric or campanulate. 

 Tips of the involucral bracts foliaceous. 

 Tips of the involucral bracts merely spreading or 

 squarrose. 

 Bracts glandular. 

 Bracts glabrous or merely ciliate. 

 Involucre turbinate. 

 Tips of the involucral bracts erect or appressed. 

 Bracts coriaceous, obtuse. 

 Bracts herbaceous, acute or acuminate. 

 Rays typically white : sometimes purplish. 



t Heads in panicles or terminating elongated branches or ra- 

 cemes: plants profusely ramuliferous and twiggy. T7»)- 

 i7ieal Asters, Nos. 74-87. 

 Heads more or less scattered, their pedicels prolonged, copi- 

 ously and minutely leafy. 

 Rameal leaves merely firm : most pedicels not over 3 cm. 

 • long. 



Rameal leaves rigid, spreading, very conspicuous but 

 minute: pedicels often 12 cm long. 

 Heads paniculate or racemose, on branchlets which are 

 relatively inconspicuous and not copiously foliolose. 

 Bracts, at least the lower ones, very obtuse : plants very 

 1 ough-pubescent. 



48. A. conthmns. 



49. A. patcntissimus. 



.50. A. patrvs. 



51. -4. teniiicaulis. 



52. A. subsessilis. 



53. A. phlogifolius. 



54. A. nblongifoliua. 



55. A. Kumleinii. 



56. A. Novae- Angliaf. 



57. .4. Carolinianus. 



58. A. jmniceuif. 



62. A. Novi-Belgii, 



63. A. elodes. 



59. A. Elliott n. 



60. A. cdnduplicatus. 



.58. A. piiniccns. 

 62. .4. Novi-Bclgii. 



61. A. prcnanVwides. 



64. ,4. Sfvirens. 



65. ^4. phyllolepu. 



66. A. concolor. 



67. .4. adnatus. 



68. A. sr/unrro-tus. 



69. A. grandiflovm. 



13. A. mirabilis. 



70. A. Curtisii. 



71. ^4. sprctabilis. 



72. A. siircidosiis. 



73. .4. gracilis. 



47. A. tiirbinellus. 

 86. A. Priceae. 



74. A. dumosus. 



75. A. coridij'olius. 



