Alisma gramineum
Grass alisma, Grass Alisma, grass alisma, grass alisma
(c) Thomas Gyselinck, some rights reserved (CC BY), uploaded by Thomas Gyselinck · licence
Family: Alismataceae · Type: Herb · Native
Conservation status: CNPS 2B.2
Alisma gramineum (Grass alisma) is a native California herb in the Alismataceae family, recognized by distinctive narrow linear leaves.
Grass alisma is a rare (CNPS 2B.2) California native perennial found in the Modoc Plateau in ponds at elevations of 1,200 to 1,800 meters. Flowering from summer to fall, this plant produces white to pink flowers with delicate petals and a distinctively coiled style. Growing with slender stems, it develops long, narrow leaves 6 to 30 centimeters in length with linear to narrowly lanceolate blades 3 to 7 centimeters long and 0.8 to 2 centimeters wide. Its leaf blades taper gracefully at the base, creating an elegant profile in aquatic environments. The fruit features thick, opaque lateral walls, characteristic of this distinctive aquatic plant.
Identification and appearance
Key characters: Geographically isolated; distinctive narrow linear leaves
Habitat and range
Habitat: Ponds
Elevation: 1200-1800 m
Outside California: to Canada, eastern United States, Eurasia
Bloom period
Alisma gramineum blooms Summer-fall.
Conservation status
CNPS 2B.2
How to tell it apart
vs Echinodorus: Alisma fruits sit flat in a ring; burhead fruits spiral on a dome forming a bur.; vs Sagittaria: Alisma flowers have both male and female parts; arrowhead has separate male and female flowers.; vs Rumex: Alisma has three white petals and aquatic habit; dock has tiny greenish flowers and terrestrial habit.; vs Potamogeton: Alisma has three white petals above water; pondweed has tiny flowers and submerged leaves.; vs Plantago: Alisma has three distinct white petals; plantain has tiny four-part flowers in dense brown spikes.
Frequently asked questions
Is Alisma gramineum native to California?
Yes. Alisma gramineum is native to California (recorded as native).
When does Alisma gramineum bloom?
Alisma gramineum blooms Summer-fall.
What plant family does Alisma gramineum belong to?
Alisma gramineum is in the Alismataceae family, genus Alisma.
Is Alisma gramineum rare or endangered?
Alisma gramineum carries California Rare Plant Rank 2B.2, state rank S3.
What habitat does Alisma gramineum grow in?
Alisma gramineum grows in Ponds.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
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.