COMPOSITAE (COMPOSITE FAMILY) 



807 



* * * Leaves whitened, silvery-silky both sides, all sessile and entire, mucronu- 



late ; involucre imbricated in ^-several rows ; rays showy, purple-violet. 



16. A. serlceus Vent. Stems slender, 2-6 dm. high, 

 branched ; leaves silver-white, lanceolate or oblong ; heads 

 mostly solitary, terminating the short branchlets ; bracts 

 of the globular involucre similar to the leaves, spread- 

 ing, except the short coriaceous base ; achenes smooth, 

 many-ribbed. Prairies and dry banks, 



Wise, to Man., Tex., and Tenn. Aug.- 

 Oct. Heads large; rays 20-30. FIG. 

 933. 



17. A. c6ncolor L. Stems wand-like, 

 nearly simple, 3-9 dm. high ; leaves 



o A crowded, oblong or lanceolate, appressed, 



the upper reduced to little bracts ; heads 

 in a simple or compound wand-like raceme ; bracts of the 

 obovoid involucre closely imbricated in several rows, appressed, 

 rather rigid, silky, lanceolate ; achenes silky. Dry sandy soil 

 near the coast, Mass., and south w. Late Aug.-Nov. FIG. 934. 



* * * * Leaves entire, the lower not heart-shaped, the cauline all with sessile and 



cordate-clasping base, the auricles generally meeting around the stem. 



18. A. patens Ait. Rough-pubescent ; stem loosely pan- 

 icled above, 3-9 dm. high, with widely spreading branches ; 

 heads mostly solitary, terminating slender branchlets, 1-2 

 cm. broad, with showy deep blue-purple rays ; leaves 

 oblong-lanceolate or ovate-oblong, often contracted below 

 the middle, rough, especially above and on the margins, 

 the cauline 2.5-7 cm. long ; bracts of the minutely rough- 

 ish involucre with spreading pointed tips ; achenes silky. 

 Dry ground, centr. Me. to Minn., and southw. Aug.- 

 Oct. FIG. 935. Var. piiLOGiF6Lius Nees. A form 

 usually of shady places, with the larger (6-15 cm. long) 

 and elongated thin scarcely rough leaves downy under- 

 neath, sometimes toothed toward the end, mostly much 

 contracted below the middle. (A. phlogifolius Muhl.) 



A. concolor. 



A. patens. 



Mass, to O. and Tenn. 



Var. gracilis Hook. Stem-leaves very short (1-2 cm. long), thickened and 

 harsh, those of the flowering branches mostly minute. Ky. to Kan., and 



southwestw. 



***** Lower leaves heart-shaped and petioled; no glandular or viscid pubes- 

 cence; heads with short and appressed green-tipped bracts (except in nos. 

 19 and 26), mostly small and numerous, racemose or panicled. 



H- Heads middle-sized, with many rays, and squarrose foliaceous involucre. 



19. A. an6malus Engelm. Somewhat pubescent and 

 scabrous ; stems slender, 1 m. high, simple or racemose- 

 branched above ; leaves ovate or ovate-lanceolate, pointed, 

 entire ; the upper small, almost sessile ; bracts of the hemi- 

 spherical involucre imbricated in several rows, appressed, 

 with linear spreading leafy tips ; achenes smooth. Lime- 

 stone cliffs and rocky woods, 111., Mo., and Ark. Sept., 

 Oct. Rays violet-purple. FIG. 936. 



H- t- Rays 10-20 ; involucral bracts appressed or erect. 



w- Leaves entire or slightly serrate; heads middle-sized; 

 rays bright blue. 



20. A. azureus Lindl. Stem rather rough, erect, racemose- 

 compound at the summit, the branches slender and rigid ; 936. A. anomalus. 



