Please try our next iteration of the Michigan Flora Online here. Beginning on February 1, 2023, will point to this new site.

The new site offers several benefits over the existing website, including real coordinate mapping, giving a clearer view of the density of documentation as well as more precision about plant distributions and their link to landforms. We will also have the ability to update species pages more regularly, both in terms of new collections and as more existing Michigan specimens are georeferenced. In addition, we have a better photo display, and offer indented keys.

Parthenium integrifolium L.
Synonym: Parthenium hispidum
Coefficient of Conservatism: *
Coefficient of Wetness: 5
Wetness Index: UPL
Physiognomy: Ad P-Forb

Including P. hispidum of Michigan Flora

Native in prairie remnants in adjacent Indiana (and beyond), and should be sought in southwestern Michigan. Not collected until 1936 (Kalamazoo Co.), our occurrences represent either waifs or escapes from cultivation into fields, along railways, and other disturbed open areas, or persisting from so called prairie plantings (as in Lenawee Co.) Plants with the upper leaves clearly auriculate-clasping and larger heads have been segregated as var. hispidum (Raf.) Mears or P. hispidum Raf., but are now considered part of the variation of P. integrifolium.


Alger County
Kalamazoo County
Keweenaw County
Lenawee County


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. January 30, 2023.