Silphium integrifolium Michx. - Rosin Weed


 

|  back  | forward |

Silphium integrifolium - (image 1 of 7)

 

Taxonomy

Family: Asteraceae

Habitat

Prairies, calcareous fens.

Associates

In prairies with Allium cernuum, Andropogon gerardii, Aster ericoides, Baptisia leucantha, Cassia fasciculata, Coreopsis tripteris, Desmodium illinoense, Eryngium yuccifolium, Fragaria virginiana, Helianthus grosseserratus, Helianthus mollis, Monarda fistulosa, Pathenium integrifolium, Ratibida pinnata, Solidago graminifolia nuttallii, Solidago rigida, Spartina pectinata, Thalictrum dasycarpum hypoglaucum. Associate in calcareous fens include Cacalia pantaginea, Oxypolis rigidior, Parnassia glauca, Valeriana ciliata.

 Distribution

Southern MI to NE, south to AL, MI, and TX

Morphology

Coarse, stiff, herbaceous perennial, to 5' high. Leaves opposite, scabrous below, sessile, often clasping, entire or slightly toothed, ovate or lance ovate to elliptic. Stems terete or subterete. Heads many flowered; rays yellow, mostly 16-35, 5 cm long; disk mostly 1.5-2.5 cm wide; phyllaries scabrous or pubescent, eglandular. Fruit an dark, smooth achene, resembles a large sunflower seed.

Notes

Flowers mid July to mid August

Wetland indicator: Upland

Exudes a resinous substance when cut.

References

Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Second Ed.
The New York Botanical Garden. Bronx, NY

 

Swink, F. and G. Wilhelm. 1994. Plants of the Chicago Region.
Indiana Academy of Science. The Morton Arboretum. Lisle, Illinois.

 


Home

 

 Michael Hough 2005