Sagittaria calycina Engelm.
CC = 4
CW = -5
MOC = 50
Family - Alismataceae
Habit - Annual forb.
Stems - Aerial stems absent.
Leaves - All basal, erect to reclining, to 1 m, glabous. Petioles spongy, inflated and rounded to flattened, the blades of submerged leaves absent or linear, the blades of emergent leaves broadly sagittate to hastate, less commonly lanceolate and unlobed.
Inflorescences - Usually unbranched racemes, erect to ascending in flower, prostrate in fruit, typically shorter than leaves, the flowers paired or whorled at nodes. Bracts at nodes of the inflorescence 3-12 mm long, fused in the basal half, the free portions broadly triangular, obtuse.
Flowers - Lowest 1-8 whorls of flowers perfect, on short, thickened, recurved pedicels 12-50 mm long. Sepals 3, green, appressed to ascending in fruit. Petals 3, white with yellow base. Filaments of stamens longer than the anthers, not swollen basally, minutely hairy. Pistils many, in a dense spiral cluster on the globose, expanded receptacle.
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.
Flowering - June - September.
Habitat - Emergent aquatics along muddy pond margins, ditches, sloughs, sluggish streams, and rivers; sometimes flowering in dried mud.
Origin - Native to the U.S.
Other info. - This species of arrowhead occurs throughout most of Missouri. Elsewhere its range is somewhat scattered across the central U.S., with somewhat disjunct populations in California and Oregon. It is probably the easiest Sagittaria to identify with confidence, as it is the only Missouri species with such thick, decumbent pedicels. In addition, the fruit clusters are pendent and encased in the persistent sepals, which are strongly appressed to the clusters.
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).