Aquatic and Wetland Vascular Plants of the Northern Great Plains

Alismataceae - The Water Plantain Family

Perennial or annual, acaulescent herbs, emergent, stranded or less commonly submersed in habit, often with tuber-bearing rhizomes or cormose at the base when perennial, fibrous-rooted. Leaves simple, all basal; blades of floating or emersed leaves oblong-elliptic, lanceolate, ovate or sagittate, often linear when submersed; petioles broadly winged at the plant base, somewhat sheathing. Inflorescence a terminal compound panicle with whorled branches, or the flowers mostly in whorls of 3 in a simple or sparsely branched raceme, the whorls of branches or flowers subtended by bracts. Flowers perfect, imperfect or both, regular, hypogynous; sepals 3, greenish; petals 3, white or pinkish; stamens 6-many; pistils several to numerous, maturing into laterally flattened or turgid, often beaked achenes.

Lead	Characteristic	Go To
1	Pistils or achenes in a single whorl on a flat receptacle, mostly fewer than 20.	Genus Alisma
1	Pistils or achenes numerous and crowded in a dense cluster on a globose receptacle.	Lead 2
2	Flowers mostly imperfect, with the male above the female in the inflorescence; achenes laterally flattened and winged; leaves usually sagittate.	Genus Sagittaria
2	Flowers all perfect; achenes turgid, strongly ribbed; leaves never sagittate.	Genus Echinodorus

51. Alismataceae, the Water Plantain Family

1. Alisma L. -- Water plantain

1. Alisma gramineum Gmel.

2. Alisma plantago-aquatica L.

2. Echinodorus Rich. -- Burhead

1. Echinodorus rostratus (Nutt.) Engelm.

3. Sagittaria L. -- Arrowhead, duck potato

1. Sagittaria brevirostra Mack. & Bush

2. Sagittaria calycina Engelm.

3. Sagittaria cuneata Sheld.

4. Sagittaria graminea Michx.

5. Sagittaria latifolia Willd.

6. Sagittaria rigida Pursh

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