Photo: Sagittaria rigida

Sagittaria rigida Pursh

Stiff Arrowhead

Habitat: Calcareous or brackish mud or water. [Tidal wetland (non-forested, wetland)]

Range: Maine and Quebec to Minnesota, south to Virginia, Tennessee, Missouri, and Nebraska.

Aids to Identification: Arrowheads are aquatic plants with 3-petalled white flowers and numerous stamens and carpels. The septate nodulose roots are distinctive. The identification of stiff arrowhead is complicated by the fact that its form is highly variable, depending upon the habitat in which it is growing. It can be distinguished from other arrow-head species by its leaves, which usually lack basal lobes, and by its sessile (stalkless) fruits and pistillate white flowers.

Photo: Sagittaria rigida
Photo: Sagittaria rigida leaves

Ecological characteristics: In Maine, this species is typically found in fresh to brackish tidal mud flats.

Photo: Sagittaria rigida specimen

Phenology: Flowers July - September.

Family: Alismataceae

Synonyms: None noted.

Known Distribution in Maine: This rare plant has been documented from a total of 13 town(s) in the following county(ies): Kennebec, Lincoln, Penobscot, Sagadahoc, York.

Reason(s) for rarity: At northern limit of range.

Conservation considerations: Prevent degradation of marsh and estuary habitat from adjacent land uses.

Photo: Sagittaria rigida