128 - 



171a. Basal leaves obovate Ragwort, Senecio obovatus. 



171b. Basal leaves oblong Ragwort, Seneeio balsamitae. 



172a. Introduced annual in waste places (1 4 dm. high; spring 



and summer) Groundsel, Senecio yulgaris. 



172b. Native biennial in moist ground (3 8 dm. high; summer) 



Squaw Weed, Senecio discoidens. 



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 Tar. snlliTantii. 

 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, grad- 

 ually narrowed to a sessile or short-petioled base (5 20 dm. 

 high) Sunflower, Helianthus scaberrimus. 



181a. Disk less than 2 cm. wide (310 dm. high) 



Sunflower, Helianthus petiolaris. 

 181b. Disk more than 2.5 cm. wide (1 3 m. high) 



Sunflower, Helianthus annuus. 



