Sagittaria rigida
Sessile-fruited arrowhead
(c) Ryan Sorrells, some rights reserved (CC BY) · licence
Family: Alismataceae · Type: Herb · Not Native
Sagittaria rigida (Sessile-fruited arrowhead) is a non-native California herb in the Alismataceae family, recognized by bent scape, sessile female flowers, and dilated pubescent filaments.
Sessile-fruited arrowhead is a naturalized perennial herb found in ponds, streams, and marshes in the northern California Central Valley, northern Sierra Nevada foothills, and northern Coast Ranges at elevations of 6 to 1,385 meters. Flowering from May to August, this plant produces white flowers with distinctive staminate flowers featuring dilated, pubescent filaments. Growing with tubered stems that bend at the inflorescence, the plant develops both submersed and emergent leaves, with underwater leaves having blade-like petioles and emergent leaves featuring linear to elliptic blades that can be hastate or sagittate in shape. Its emergent leaves have blade-like or three-angled petioles, creating a distinctive structural profile in aquatic environments. The fruit features a recurved beak measuring 0.8 to 1.4 millimeters long, with sepals that become reflexed when the fruit matures.
Identification and appearance
Key characters: 5 sympatric species; key features are bent scape, sessile female flowers, and dilated pubescent filaments
Habitat and range
Habitat: Ponds, streams, marshes
Elevation: 6-1385 m
California counties: Tehama, Plumas, Marin
Outside California: Washington, Idaho, Saskatchewan, eastern North America
Bloom period
Sagittaria rigida blooms May-Aug.
How to tell it apart
vs Alisma: Sagittaria has separate male and female flowers; alisma flowers have both parts together.; vs Echinodorus: Sagittaria fruit clusters lack the spiky bur appearance of burhead.; vs Ranunculus: Sagittaria has three white petals and aquatic habit; buttercup has five yellow petals.; vs Damasonium: Sagittaria fruits spiral on a dome; damasonium fruits fuse at base in a flat star.; vs Plantago: Sagittaria has three-petaled white flowers; plantain has tiny flowers in brown spikes.
Frequently asked questions
Is Sagittaria rigida native to California?
No. Sagittaria rigida is not native to California (recorded as not native).
When does Sagittaria rigida bloom?
Sagittaria rigida blooms May-Aug.
Where in California does Sagittaria rigida grow?
Sagittaria rigida occurs in Tehama, Plumas, Marin, at elevations of 6-1385 m.
What plant family does Sagittaria rigida belong to?
Sagittaria rigida is in the Alismataceae family, genus Sagittaria.
What habitat does Sagittaria rigida grow in?
Sagittaria rigida grows in Ponds, streams, marshes.
Related species
Other California species in the same genus, family, or bioregion.
- Sagittaria sanfordii — Sanford's arrowhead
- Sagittaria sp. — Arrowhead
- Sagittaria cuneata — Arum leaved arrowhead
- Sagittaria latifolia — Broad leaf arrowhead
- Sagittaria longiloba — Long lobed arrowhead
- Sagittaria montevidensis subsp. calycina
- Alisma gramineum — Grass alisma
- Alisma lanceolatum — Lanceleaf water plantain
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.