Helianthus pauciflorus Nutt.
Common Name: STIFF SUNFLOWER
Coefficient of Conservatism: 5
Coefficient of Wetness: 5
Wetness Index: UPL
Physiognomy: Nt P-Forb

Presumably formerly native to Michigan prairies and collected by the First Survey on the "Edwards Prairie" in Cass Co. in 1838. Recent collections (over the past 75 years) are from railroads, fields, and roadsides in situations that suggest they are adventive from farther west or escapes from cultivation.

The leaves are usually ± reduced on the upper part of the stem, although not as much so as in H. occidentalis. The blades are ± elliptic, tapering into short or indistinct petioles.

Helianthus ×laetiflorus Pers. is now interpreted to apply to a hybrid between H. pauciflorus and H. tuberosus. It differs from the former in having yellow disk corollas and in general somewhat more acute phyllaries. It is cultivated and the sporadic occurrences probably represent escapes (Allegan, Benzie, Berrien, Ingham, Kalamazoo, Kent, Lenawee, Marquette, Midland, and Washtenaw Cos.).

Locations

Alger County
Allegan County
Cass County
Cheboygan County
Delta County
Emmet County
Houghton County
Jackson County
Kalamazoo County
Keweenaw County
Lapeer County
Lenawee County
Marquette County
Menominee County
Monroe County
Oakland County
Ontonagon County
Schoolcraft County
St. Joseph County
Van Buren County
Washtenaw County
Wayne County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 14, 2017. http://michiganflora.net/species.aspx?id=356.