Coefficient of Conservatism:
Coefficient of Wetness:
R. W. Smith
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.).