COMPOSITE. 123 



11. A. tardiflo'ms, L. Rays pale violet. Stem glabrous 

 or nearly so, 1-2 feet high. Leaves lanceolate or oblong- 

 lanceolate, acuminate, with tapering and somewhat auricled 

 base. Heads few, as a rule. Involucre loose, the outer 

 scales leaf-like. Atl. Prov. 



***None of the leaves heart-shaped; those of the stem sessile, tapering 

 at tlie base (except in No. 11). 



12. A. rad'ula, Ait. Bays light violet. Eadical leaves 

 all tapering into margined petioles. Stem-leaves sessile, 

 oblong-lanceolate, pointed, sharply serrate in the middle, 

 very rough both sides, rugose. Scales of the bell-shaped 

 involucre oblong, appressed, with slightly spreading herb- 

 aceous tips. Low grounds, Atl. Prov. 



13. A. erieoi'des, Ait. Rays white or nearly so. Stem 

 smooth or nearly so, 1-3 feet high, the branchlets or ped- 

 uncles racemose on the upper side of the spreading branches. 

 Lowest leaves oblong-spathulate, the others linear-lance- 

 olate or linear-awl-shaped. Barren soil, and margins of 

 lakes and rivers. Var. villOSUS, Torr. and Gray, has hairy 

 stems and leaves. 



14. A. multiflo'rus, Ait. Rays white, 10-20. Stem pale 

 or hoary with minute pubescence, 1 foot high, bushy. 

 Leaves crowded, linear, with rough margins ; the upper 

 partly clasping. Heads small, crowded on the racemose 

 branches. Scales of the involucre with spreading green 

 tips. Dry soil. 



15. A. Tradesean'ti, L. (A. tenuifolius,} Rays white or 

 purplish. Scales of the involucre narrowly linear, in 3 or 4 

 rows. Heads small, very numerous, in 1-sided close racemes 

 on the branches. Stem 2-4 feet high, much branched, 

 smooth. Leaves linear-lanceolate, with long slender point, 

 the larger ones with a, few remote teeth in the middle. Low 

 grounds. 



16. A. diffu'SUS, Ait. (A. miser, L.) Rays pale blue or 

 whitish. Involucre nearly as in No. 15. Stem more or less 

 pubescent, much branched. Heads small, in loose 1-sided 



