Etymology: Silphium: old Greek generic name referring to resinous juice
Plants: erect, perennial, 3'-8' tall forb; stems square in X-section, mostly smooth
Leaves: opposite, strongly toothed, upper and lower leaves about the same size, surrounding the stem to form a cup
Flowers: head 1 3/4"- 2 3/4" wide with 16-35 (usually 21 or 34) yellow rays 1/2"-1 1/2" long, disk 1/2"-1" wide; inflorescence of several heads in an open, branched cluster; blooms July-Sept.
Fruits: dry seed with no fluffy pappus
Habitat: full to partial sun; wet to moderate moisture; prairies, woods, streambanks; in sandy, loamy soil
Conservation Status: Native
Flora of North America: Flora of North America Floristic Rating: Coefficient of Conservatism = 4, Wetland Indicator = FACW- Wisconsin Natural Resources Magazine: Information and Photos Atlas of the Wisconsin Prairie and Savanna Flora: by T.S. Cochrane & H.H. Iltis: habitat, distribution infomation / flowering and fruiting times USDA Plants Database: Federal Distribution and detailed information including photos Dan Tenaglia's The Missouri Flora: Fabulous photographs; detailed descriptions; color and leave arrangement key. David G. Smith's "Delaware Wilflowers": Beautiful photographs; descriptions Illinois Wildflowers: Wonderful photographs; detailed descriptions; color and leaf arrangement key Southwest School of Botanical Medicine: Britton & Brown Illustrated Flora - 2nd Edition (1913) "An Illustrated Flora of the Northern United States and Canada"