S02 



COMPOSITAE (composite FAMILY) 



Rays 6 mm. or less long ; leaves slightly serrate . . 41. A. TVadescantt. 

 Rays longer ; leaves entire . . (42) A. paniculaius, v. bellidijlorus. 

 Branches divaricate ; small heads in 1 -sided racemes . 39. A. mmineus. 



Branches ascending, terminated by solitary heads (39) A. mmineus, v. saxaiilis. 

 Eays violet or rose-pink (exceptionally white). 

 Leaves at most 4.5 cm. long, becoming re volute . . 55. ^. nemoralis. 



Leaves longer, plane 44. .4. junceus. 



f Involucre more than 5 mm. high Y. 



T. Bracts with definite firm subulate tips 32.-4. polyphyllus, 



Y. Bracts without firm subulate tips Z. 

 Z. Leaves at most 4.5 cm. long. 



Stems many, rigid, from a woody caudex ; bracts firm, the 



inner blunt ; rays blue-violet bl. A. linariifolius. 



Stem single, from a slender rootstock ; bracts thin, linear- 

 attenuate ; rays rose-pink 55.-4. nemoralis. 



Z. Leaves longer a. 

 a. Annuals, \vith inconspicuous rays. 



Bracts definitely imbricated, linear or linear-subulate . 57. A. subulatus. 

 Bracts subequal, the outer foliaceous. 

 Leaves linear-attenuate ; rays shorter than the style . 58. A. angusius. 

 Leaves linear-oblanceolate to spatulate ; rays longer than 



the style ... .... §9. A.frondosus. 



a. Perennials, with mostly conspicuous rays b. 

 b. Bracts firm, lanceolate. 



Bracts unequal, regularly imbricated, not foliaceous . 56. A. tenuifolius. 

 Bracts subequal or imbricated, with spreading foliaceous 



tips 1. A. palAJLdosus. 



b. Bracts thin, linear or linear-lanceolate. 



Bracts with conspicuous eUiptic or subrhombic green tips. 

 Heads terminating minutely foliose-bracteolate branch- 

 lets 38. ^. dumosus. 



Heads paniculate, or if few on leafy (not minutely 



foliose-bracteolate) branches 43.-4. salidfoUus. 



Bracts without conspicuous colored tips. 



Eays white ; bracts very narrowly linear-attenuate, 



regularly imbricated, 4-6 mm. long (42) A. paniculaius, v. belUdiJlortu 

 Eays violet or rose-pink ; bracts linear-lanceolate, less 



definitely imbricated, mostly longer . . .44. A.junceus. 

 U. Stem conspicuously pubescent. 



Involucral bracts (or at least the outer ones) bristly-ciliate. 

 Leaves crowded, rigid ; rays white (rarely purple-tinged). 



Heads 5-6 mm. high 36. ^. mulUflorus. 



Heads 7-9 mm. high 37. yl. cojnmutatus. 



Leaves not rigid ; rays blue c .35.-4. amethystinus. 



Irvolucral bracts not bristly-ciliate. 

 Bracts with firm subulate tips ; short rays usually white. 

 Involucre hemispherical or campanulate, as broad as high (38) A. ericoides, v. villosust 

 Involucre turbinate, narrower than high . . (84) A. depauperatus, v. parviceps. 

 Bracts thin, linear-attenuate, without firm subulate tips ; stem 



puberulent; long rays violet or rose-pink . . . .55. A. nem,oralis. 

 T. Stem-leaves lanceolate or broader c. 



c. Heads in flat-topped corymbs ; rays white or whitish (not blue or violet). 



Leaves rigid, linear-lanceolate ; pappus simple . . . o . 58. A. piarmicoidM, 

 Leaves not rigid, broader ; pappus double. 

 Involucre 3-4.5 mm. high ; leaves lanceolate to ovate . . .50. A. umbellatus. 

 Involucre 5-7 ram. high ; leaves obovate to oblong . . .51. A. vnf/rmus. 

 C. Heads paniculate or racemose d. 

 d. Stems glabrous or essentially so e. 

 e. Involucre 5 mm. or less high. 



Bracts with definite firm subulate tips . . . . .38.-4. ericoides. 

 Bracts without firm subulate tips. 

 Heads in more or less 1 -sided racemes. 

 Leaves narrowly lanceolate, scarcely serrate ; bracts linfcar- 



attenuate .39.-4. vimineus. 



Leaves broader, serrate ; bracts with the midrib dilated 



upward and rather conspicuous 40. A. laterifloruB. 



Heads on ascending-paniculate branches. 

 Bracts linear-attenuate. 

 Heads (including rays) 1-1.5 cm. broad; bracts very 



slender and green 41. .4. Tradescanti. 



Heads larger ; bracts green chiefly at tip . . . . 42. A. paniculatus. 

 Bracts broad-linear or linear-oblong, with conspicuous 



elliptic or subrhombic green tips 43.-4. salicifolius. 



e. Involucre more than 5 mm. high /. 



/. Bracts with definite firm subulate tips 32.-4. polyphyllm. 



f. Bracts without firm subulate tips g. 

 g. Leaves on branchlets reduced to rigid subulate bracts. 



Perennial ; inrolucre 9 mm. or more high, of firm closely 



imbricated bluntish bracts 28. 4. turbineUus. 



