Glyceria declinata
Low manna grass, Low Manna Grass
(c) Thomas Gyselinck, some rights reserved (CC BY), uploaded by Thomas Gyselinck · licence
Family: Poaceae · Type: Grass · Not Native
Conservation status: Cal-IPC Yes
Glyceria declinata (Low manna grass) is a non-native California grass in the Poaceae family, recognized by 3-lobed lemma tips and short anthers diagnostic, disturbed habitat preference.
Low manna grass is a naturalized perennial herb found in northern California Coast, Klamath Ranges, northern Coast Ranges, and other regions including Central Valley and Southern California in vernal pools, freshwater marshes, and seasonally wet areas at elevations below 1,300 meters. Flowering from May to June, this grass produces small, narrow spikelets in compact clusters approximately 6 to 30 centimeters long. Growing as a tufted perennial with rhizomes, it forms dense clumps with stems 20 to 90 centimeters tall and 1.5 to 2.5 millimeters in diameter. Its leaves have narrow blades 3 to 12 centimeters long and 1.5 to 6 millimeters wide, with ligules 4 to 9 millimeters long. Each spikelet contains 5 to 14 florets with lemmas that have distinctive three-lobed tips.
Identification and appearance
Key characters: 7 sympatric species; 3-lobed lemma tips and short anthers diagnostic, disturbed habitat preference
Habitat and range
Habitat: Common. Vernal pools, freshwater marshes, disturbed, seasonally wet areas
Elevation: < 1300 m
California counties: Calaveras, Humboldt, Marin, Shasta, Riverside, Tehama, San Benito, Sonoma, Tulare, Solano, Siskiyou, Yuba, Sacramento, Sutter, Amador, Butte, San Joaquin, Nevada, Mendocino, Santa Cruz, Contra Costa, Plumas, Placer, Merced, Mariposa, Lake, Stanislaus, San Luis Obispo, Fresno, Monterey, Yolo, San Diego, Madera
Outside California: British Columbia, eastern United States, native to Europe
Bloom period
Glyceria declinata blooms May-Jun.
Conservation status
Cal-IPC Yes
How to tell it apart
vs Pleuropogon: Glyceria has closed leaf sheaths and 1-veined upper glumes; Pleuropogon has open sheaths and distinctive bumpy, jointed spikelet axes.; vs Oloptum: Glyceria has closed sheaths in wetlands; Oloptum has open sheaths in dry sites with needle-like rolled leaves.; vs Torreyochloa: Glyceria has 1-veined upper glumes; Torreyochloa has 3-veined upper glumes and more prominent lemma veining.; vs Puccinellia: Glyceria has closed leaf sheaths in freshwater; Puccinellia has open sheaths in saline/alkaline sites.; vs Desmazeria: Glyceria is perennial in wetlands with closed sheaths; Desmazeria is annual of dry sites with open sheaths.
Frequently asked questions
Is Glyceria declinata native to California?
No. Glyceria declinata is not native to California (recorded as not native).
When does Glyceria declinata bloom?
Glyceria declinata blooms May-Jun.
Where in California does Glyceria declinata grow?
Glyceria declinata occurs in Calaveras, Humboldt, Marin, Shasta, Riverside, Tehama, San Benito, Sonoma and other counties, at elevations of < 1300 m.
What plant family does Glyceria declinata belong to?
Glyceria declinata is in the Poaceae family, genus Glyceria.
Is Glyceria declinata invasive in California?
Glyceria declinata is listed by Cal-IPC with an invasiveness rating of Yes.
Related species
Other California species in the same genus, family, or bioregion.
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.