Protologue Description: BIDENS EATONI, var. kennebecensis, n. var., achaeniis exterioribus 8.8-9.8 mm. longis, interioribus 9.5-10.5 mm. longis.
Outer achenes 8.8-9.8 mm. long, the inner 9.5-10.5 mm. long.- MAINE, tidal reaches of the lower Kennebec system: tidal mud-flats and swales by Cathance River, Bowdoinham, September 14 and 19, 1916, Fernald & Long, nos. 14822 (TYPE in Gray Herb.), 14,823, also in Plantae Exsiccatae Grayanae, no. 297; border of salt-marsh , Back River Creek, Woolwich, September 15, 1916, Fernald & Long, no. 14,824.