errate; 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.