ALISMATACEAE

WATER-PLANTAIN FAMILY

Charles E. Turner

Annual, perennial herb from corms, stolons, rhizomes, or tubers, aquatic (± emergent or on mud), generally bisexual; roots fibrous
Stem: caudex short
Leaves: basal, simple, palmately veined, sometimes floating; submersed blades generally linear to ovate; emergent blades linear to sagittate
Inflorescence generally scapose, umbel- to panicle-like; flowers whorled, in interrupted clusters
Flowers bisexual or unisexual, radial; sepals 3, generally green, generally persistent; petals 3, generally > sepals, white or pink; stamens 6–many; pistils 6–many, generally simple
Fruit: achene, generally compressed, beaked
Genera in family: ± 12 genera, 75–100 species: especially n hemisphere
Reference: [Rogers 1983 J Arnold Arbor 64: 383–420]

SAGITTARIA

ARROWHEAD, TULE POTATO, WAPATO

Annual, perennial herb, generally monoecious; roots partitioned
Leaves: petiole unangled; submerged blades tapered to base; floating or emergent blades generally sagittate (or linear to ovate)
Inflorescence: lowest node generally with 3 pistillate flowers; staminate flowers above
Flowers generally unisexual; sepals 3–10 mm, reflexed to appressed in fruit; petals generally entire
Pistillate flower: receptacle convex; pistils many, in spheric cluster
Staminate flower: stamens many
Fruit: body generally 2–3.5 mm, strongly compressed, back winged or ridged; beak generally lateral, spreading or erect
Species in genus: ± 20 species: worldwide, especially Am
Etymology: (Latin: arrow, from leaf shape)
Reference: [Bogin 1955 Mem NY Bot Gard 9:179–233]
Some species weedy; tubers of some used for human and wildlife food.

Native

S. latifolia Willd.

Perennial, sometimes dioecious; tubers oblong, ± white or bluish
Leaves: emergent blades 6–30 cm, sagittate, lower lobes ± = terminal lobe
Pistillate flower: pedicel ascending in fruit; sepals reflexed in fruit
Staminate flower: filaments glabrous
Fruit: beak 1–2 mm, spreading
Chromosomes: 2n=22
Ecology: Ponds, slow streams, ditches
Elevation: < 1500 m.
Bioregional distribution: California Floristic Province, Great Basin Floristic Province
Distribution outside California: to s Canada, e US, n S.America
Flowering time: Jul–Aug
Horticultural information: SUN, WET (fresh water): 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.