5. A. filifòlia, Torr. Suffruticose, finely canescent, 1–3° high; leaves all filiform, the lower commonly 3-parted; heads very small and numerous, crowded in a long leafy panicle.—Central Kan. to Neb., and southwestward.
§ 2. Receptacle smooth; flowers all fertile, a few pistillate, the others perfect.
Two cultivated shrubby species, from Europe, with filiformly divided leaves, have occasionally escaped from gardens and become spontaneous, viz., A. Abrótinum, L. (the Southernwood), of strict habit, with leaves 1–2-pinnatifid and pubescent heads, and A. pròcera, L., with more spreading branches, all the leaves finely 2-pinnatifid, and heads glabrous.
[*] Tall (1–5°) and branching perennials, whitened with fine and close-pressed wool; heads small, in leafy panicles.
6. A. serràta, Nutt. Very leafy, 6–9° high; leaves lanceolate or the upper linear, serrate, white-tomentose beneath, green above; heads greenish, oblong, 2´´ long or less.—Ill. to Dak.
7. A. longifòlia, Nutt. Stem 2–5° high; leaves linear or linear-lanceolate, entire, usually glabrate above; heads oblong, canescent, 2–3´´ long—Minn. to Neb., and westward.
8. A. Ludoviciàna, Nutt. (Western Mugwort.) Whitened woolly throughout; leaves lanceolate, the upper mostly entire, the lower usually cut-lobed, toothed or pinnatifid, the upper surface sometimes glabrate and green; heads campanulate, mostly sessile in narrow panicles.—Dry banks, Sask. to Mich., Ill., Tex., and westward. Very variable.
A. vulgàris, L. (Common Mugwort.) Leaves mostly glabrous and green above, beneath and the branches white-woolly, all pinnatifid, with the divisions often cut-lobed, linear-lanceolate; heads small in open panicles.—Waste places, near dwellings. (Adv. from Eu.)
[*][*] Densely white-tomentose perennial; heads large, racemose-glomerate.
9. A. Stelleriàna, Bess. Stout, 1–2° high, from a creeping base; leaves obovate or spatulate, pinnatifid, the lobes obtuse.—Sandy sea-beaches, E. Mass.; locally nat. from N. E. Asia?