Carex vacillans Drej. ex Hartman
Habitat: Saline, brackish shores, swales, salt and intertidal marshes. [Tidal wetland (non-forested wetland)]
Range: Maritime provinces and Quebec south to Massachusetts. Also in Scandinavia.
Aids to Identification: Members of this genus can be difficult to identify without careful examination of microscopic features and knowledge of general groups of species. Carex vacillans is a member of the section Phacocystis, a group recognized by its beakless perigynia on peduncled spikes (sometimes appearing sessile). Carex vacillans has erect spikes and perigynia with a short awn. C. vacillans is often confused with C. recta. In some past manuals, C. vacillans has been incorrectly applied to C. recta. Carex vacillans has conspicuously nerved perigynia with dense papilose hairs on the surface. The achenes are dull and weakly invaginated. Carex recta has short papillose and an inconspicuously nerved perigynia, with strongly invaginated achenes.
Ecological characteristics: Possibly of hybrid origin between Carex. nigra and C. paleacea. Only recently recognized as an individual species. Included in C. recta in past treatments. Known only from saltmarshes in Maine.
Phenology: Fruiting in June through August.
Synonyms: Carex x super-goodenoughii (Kükenth.) Lepage
Known Distribution in Maine: This rare plant has been documented from a total of 4 towns in the following county(ies): Hancock, Washington.
Reason(s) for rarity: Restricted range, scarcity of suitable habitat.
Conservation considerations: Disturbances to salt marshes could be detrimental to populations.