216a. Rare plants of the Northern Peninsula, with entire leaves and stems 1-5 dm. high, from a thick woody root (flowers white or purple, summer) --217. 216b. Common species, with erect stems from fibrous roots; leaves toothed (except in one species) --218. 217a. Heads 3-5 cm. wide; rays about 100 =Fleabane, Erigeron glabellus.= 217b. Heads 1-2 cm. wide; rays 20-30 =Fleabane, Erigeron hyssopifolius.= 218a. Stem unbranched, except for the peduncles; leaves chiefly basal; heads 1-9 (2-5 dm. high; flowers pale-purple, spring) =Fleabane, Erigeron pulchellus.= 218b. Stem branched; principal leaves on the stem; heads usually numerous (3-12 dm. high; spring and summer) --219. 219a. Stem-leaves linear, entire =Fleabane, Erigeron ramosus.= 219b. Stem-leaves ovate-lanceolate, the principal ones toothed --220. 220a. Rays 100 or more, light-purple or pink =Fleabane, Erigeron philadelphicus.= 220b. Rays much fewer, white =Fleabane, Erigeron annuus.= 221a. Basal leaves petioled and heart-shape at the base --222. 221b. Basal leaves not petioled; stem-leaves with heart-shape clasping bases --231. 221c. Basal and stem-leaves sessile or petioled, but never heart-shape or clasping --240. 222a. Rays white or violet --223. 222b. Rays blue --225. 223a. Plant glandular, especially on the pedicels and branches of the inflorescence =Aster, Aster macrophyllus.= 223b. Plant not glandular --224. 224a. Leaves rough above =Aster, Aster schreberi.= 224b. Leaves smooth above =Aster, Aster divaricatus.= 225a. Stem-leaves clasping the stem by a cordate base =Aster, Aster undulatus.= 225b. Stem-leaves not cordate-clasping --226. 226a. Leaves entire --227. 226b. Leaves serrate --228. 227a. Leaves glabrous above =Aster, Aster shortii.= 227b. Leaves rough above =Aster, Aster azureus.= 228a. Involucre 4-6 mm. long --229. 228b. Involucre 6-10 mm. long --230. 229a. Leaves rough; petioles mostly winged =Aster, Aster lowrieanus.= 229b. Leaves smooth; petioles slender, not winged =Aster, Aster cordifolius.= 230a. Heads few, seldom more than 10, in a loose spreading cluster =Aster, Aster lindleyanus.= 230b. Heads numerous, in a rather elongate crowded cluster =Aster, Aster sagittifolius.= 231a. Stem hirsute or rough-pubescent --232. 231b. Stem smooth, or essentially so --236. 232a. Leaves conspicuously serrate =Aster, Aster puniceus.=