Oct. 8, 2018

blue cohosh, Caulophyllum giganteum

Blue cohosh was first published by Andre Michaux in his Flora Boreali-Americana in 1803. He called it Caulophyllum thalictroides. In 1918, Merritt Fernald, in the annual report of the Michigan Academy of Science, published a description of these plants, and called this C. thalictroides, var. giganteum. Finally in 1981, Leconte and W. H. Blackwood described this as a separate species in Phytologia. That final step is now widely accepted. These plants are described as slightly larger, darker in color, and blooming about two weeks earlier when the plants are less mature. The clincher for me is the stigma. You can see it here projecting from the ovary in the center of the flower. It is about 2 mm long. Giganteum indeed! The blue berried giant blue cohosh grows in woods in KY, MA, MI, NC, NH, NY, OH, PA, TN(T), VA, VT, WV, ON, and QC. Washtenaw Co MI, 3/29/12. Please go to the blog for the other species.