Coefficient of Conservatism:
Coefficient of Wetness:
B. S. Walters
Primarily in moist interdunal flats and hollows, with some plants on associated low dunes and beaches; nearby fens and swales; limestone crevices and pavements (alvars) on Drummond Island; often with S. ohioensis (which reaches peak flowering distinctly earlier), Lobelia kalmii, and other calciphiles. This very local species, listed as threatened under both Michigan and Federal law, occurs nowhere in the world except along the northern shores of Lakes Michigan and Huron. It is very nearly endemic to Michigan.
Solidago houghtonii is a hexaploid (2n = 54), hypothesized to be derived from hybridization between S. ptarmicoides and either S. ohioensis or S. riddellii. The rays are a strong yellow and conspicuous, making this a handsome plant in bloom. Reports of S. houghtonii from inland sites in Michigan are based on diploid (and generally pale-rayed) hybrids or S. vossii. Solidago houghtonii was planted on the shore of Douglas Lake in 1935 and was sporadically observed near where planted for many years, but has apparently now died out at this site.
This and four others, S. ohioensis, S. ptarmicoides, S. rigida, and S. vossii, are the “flat-topped” goldenrods, sometimes segregated as the genus Oligoneuron.