Rudbeckia triloba L. - Brown-eyed Susan


 

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Rudbeckia triloba - (image 1 of 4)

 

Taxonomy

Family: Asteraceae

Habitat

Partly shaded ground of stream banks and shaded edges of vacant lots and fields. Often in urban settings.

Associates

 

 Distribution

VT, MA, south to FL, west to MN, NE, CO, TX.

Morphology

Biennial or short-lived perennial herb. Lower leaves trilobed or pinnatified. Bracts of the receptacle awned, mostly glabrous; disk dark purple or brown, hemispheric; rays 6-13, yellow to orange.

Notes

Flowers early August to early October

Wetland indicator: Facultative -

This species has smaller flowers than our other Rudbeckias. The tri-lobed leaves are a good identifying characteristic, usually found near the base of the plant.

Another species that frequently has tri-lobed leaves is R. subtomentosa Pursh (Sweet Black-eyed Susan). It has receptacular bracts that are densely pubescent near the tips which are obtuse to acute; the leaves downy-pubescent beneath. R. triloba has glabrous  bracts with the tips abruptly contracted into a subulate cusp; the leaves rough beneath but not downy.

The last two images might be of R. subtomentosa. It doesn't look like typical R. triloba and I didn't get pictures of the more important parts to do a positive ID.

Bibliography

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.
 


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 Michael Hough 2005