172b. Native biennial in moist ground (3-8 dm. high; summer) =Squaw Weed, Senecio discoideus.= 173a. Leaves 2-5 cm. long, sharply spinulose-serrate; involucre viscid (3-6 dm. high; summer) =Gum Plant, Grindelia squarrosa.= 173b. Leaves 5-12 cm. long, merely serrate; involucre gray-pubescent (5-15 dm. high; late summer) =Sneeze Weed, Helenium autumnale.= 174a. Disk hemispherical or oblong-cylindrical (Summer) --175. 174b. Disk flat or somewhat convex (Sunflower) (summer and autumn) --179. 175a. Disk yellow or greenish-yellow (1-3 dm. high) --176. 175b. Disk gray-brown or purple (5-15 dm. high) --177. 176a. Principal stem-leaves pinnately divided =Golden Glow, Rudbeckia laciniata.= 176b. Principal stem-leaves merely serrate =Yellow Ironweed, Actinomeris alternifolia.= 177a. Rays drooping; leaves pinnately divided =Gray-headed Coneflower, Lepachys pinnata.= 177b. Rays spreading when in bloom --178. 178a. Lower leaves deeply 3-lobed =Coneflower, Rudbeckia triloba.= 178b. Stem-leaves sharply serrate =Coneflower, Rudbeckia speciosa var. sullivantii.= 178c. Stem-leaves entire or sparingly serrate =Black-eyed Susan, Rudbeckia hirta.= 179a. Disk-flowers brown or purple --180. 179b. Disk-flowers yellow --182. 180a. Stem-leaves ovate or ovate-lanceolate; petioles prominent, not winged --181. 180b. Stem-leaves ovate or ovate-lanceolate, contracted at the base into a winged petiole (6-15 dm. high) =Sunflower, Helianthus atrorubens.= 180c. Stem-leaves oblong-lanceolate, very thick and rigid, gradually narrowed to a sessile or short-petioled base (5-20 dm. high) =Sunflower, Helianthus scaberrimus.= 181a. Disk less than 2 cm. wide (3-10 dm. high) =Sunflower, Helianthus petiolaris.= 181b. Disk more than 2.5 cm. wide (1-3 m. high) =Sunflower, Helianthus annuus.= 182a. Leaves all or chiefly at the base (5-10 dm. high) =Sunflower, Helianthus occidentalis.= 182b. Leaves chiefly scattered on the stem --183. 183a. Leaves mainly or all alternate, and not definitely 3-ribbed (1-4 m. high) --184. 183b. Leaves mainly or all opposite, lanceolate to ovate, and 3-ribbed --186. 184a. Stem glabrous =Sunflower, Helianthus grosse-serratus.= 184b. Stem hairy or rough --185. 185a. Leaves hairy beneath, rough above, lanceolate =Sunflower, Helianthus giganteus.=