Entire Leaf Rosinweed

Silphium integrifolium

A coarse perennial with large yellow composite flowers and rough, paired, oval to lance-shaped leaves. The stems are erect, occasionally branched, and nearly glabrous or velvety to rough. The leaves are evenly distributed along stems and variable, mostly opposite but sometimes alternate or in whorls of 3. They are 3 to 6 inches long, 1 to 2.5 inches wide, rough above, and rough to velvety or nearly smooth below. The flowers are yellow ray florets 1 to 2 inches long.FRUITS: Achenes, rounded, flattened, about 1/2 inch long, winged, tipped with 2 sharp teeth, enclosing small seed.CULTIVATION: Flowering Period: July, August, September. Silphium species resemble sunflowers but differ in that their ray flowers produce seeds, while in sunflowers it is the disk flowers that produce the seeds.RANGE & HABITAT: Open disturbed places and roadsides, most abundant in moist, rocky soils. Eastern 2/5 of Kansas.USES: Native Americans used the root of Whole-leaf Rosinweed as an analgesic. The plant contains a sticky resin, which gives it the name "rosinweed".