STIFF SUNFLOWER
File Size: 70 KB
 
Helianthus pauciflorus  Nutt.
[=Helianthus rigidus  (Cass. ) Desf.]
Riley County, Kansas
Perennial
Height: 1-7 feet
Family: Asteraceae - Sunflower Family
Flowering Period:   July, August, September
Stems: Erect, simple or sparsely branched above, green or often reddish, rough-hairy.
Leaves: Variable, widely separated, mostly opposite, stalked below, nearly sessile above, ovate to narrowly oblong-lanceolate, 2 to 12 inches long, 1 to 2.5 inches wide, thick, rough, leathery, gray-green; margins toothed to nearly entire; tips pointed; often folded lengthwise; uppermost leaves bract-like and sometimes alternate.
Inflorescences: Heads, solitary or several, long-stalked, terminal, 2.5 to 4 inches wide; bracts elliptic to ovate, conspicuously overlapping in several series, pressed tightly against disk, glabrous, margins fringed with stiff hairs; tips pointed to blunt.
Flowers: Ray florets 10-25, to 1.5 inch long, yellow; disk florets numerous, corollas purplish brown to sometimes yellow with reddish lobes.
Fruits: Achenes, about 1/4 inch long, mostly glabrous, tipped with 2 conspicuous bristles and smaller secondary scales, enclosing small seed.
Habitat: Dry or drying prairies, roadsides, and open woods, most abundant in sandy soils.
Distribution: East 1/2 of Kansas.
Comments: Stiff sunflower forms colonies by rhizomes and is one of our earliest blooming sunflowers. The primary roots grow more than 7 feet long.

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