Mississippi Arrowhead

Family - Alismataceae

Leaves - All basal. Petioles thick, terete, spongy, erect to reclining, to +.75m. Blades sagittate, glabrous.

Petiole bases.

Leaf blade.

Inflorescence - Typically shorter than leaves, decumbent. Flowers in whorls or pairs at nodes.

Inflorescence.

Flowers - Unisexual or perfect. Lowermost whorls usually perfect. Petals 3, white with yellow base. Sepals 3, green. Pedicels thick, to 5cm long.

Perfect flowers.

Staminate flowers.

Fruits - Fruit clusters decumbent, with appressed persistent sepals. Fruits obovate, 1.4-2.0 mm long, the beak 0.3-0.9 mm long, narrowly triangular, spreading at a right angle to the body of the fruit.

Fruits.

Flowering - June - September.

Habitat - Mud flats, wet areas.

Origin - Native to the U.S.

Other info. - This is the only Sagittaria in Missouri with such thick, decumbent pedicels. All other members of the genus in this state have the inflorescence erect and with thin pedicels. In addition, the fruit clusters are pendent, with the persistent sepals strongly appressed.
A synonym for this species is Sagittaria montevidensis Cham. & Schltdl. ssp. calycina (Engelm.) Bogin

Photographs taken along the Meramec River, Franklin County, MO, 8-19-2011, near Augusta, St. Charles County, MO, 8-27-2011, and at Riverlands Migratory Bird Sanctuary, St. Charles County, MO, 7-21-2013 (SRTurner).

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