A new entry has been added to the list of plant species known to occur in Indiana: Caulophyllum giganteum, commonly known as giant blue cohosh.
Spring wildflower enthusiasts throughout Indiana are familiar with its smaller and later blooming relative the common blue cohosh, C. thalictroides. Giant blue cohosh was previously thought to be restricted to the northeastern states and southeastern Canada.
As reported in the Indiana Native Plant and Wildflower Society (INPAWS) Journal (volume 25, issue 1), member Kimberly Miser and her mother Susie Watson were hiking last spring in Robb Hidden Canyon in Steuben County, which shares a border with both Michigan and Ohio, when they encountered a species they were unable to identify. Consultation with Indiana Department of Natural Resources State Botanist Michael Homoya and assistance provided by INPAWS member Kate Sanders provided photographs and measurements that suggested the plant was C. giganteum, but no specimen was collected to document the discovery.
Photographs and field-measurements provide preliminary evidence, but specimens are the ‘gold standard’ of botanical research because the details can be examined microscopically.
Working separately on April 6, 2018, in Martin State Forest in southwestern Indiana’s Martin County, IU botanist Daniel Layton made the same discovery. Fortunately, he had the DNR-issued permit needed to collect a specimen.