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Taxon  Report  
Glyceria declinata  Bréb.
Waxy mannagrass
Glyceria declinata is a perennial grasslike herb that is not native to California.
Cal-IPC rating: moderate
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Observation Search
(236 records)
redone or more occurrences
within a 7.5-minute quadrangle
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Bloom Period
Genus: Glyceria
Family: Poaceae  
Category: angiosperm  
PLANTS group:Monocot
Jepson eFlora section: monocot

Wetlands: Occurs usually in wetlands, occasionally in non wetlands
Name Status:
Accepted by JEF + PLANTS

Information about  Glyceria declinata from other sources

[Cal-IPC] Invasive: Glyceria declinata (waxy mannagrass) is a perennial grass (family Poaceae). Waxy mannagrass is found in the Central Valley, from Shasta County south to Fresno County. It has invaded deep vernal pools, swales, ditches, and stock ponds. Some reports indicate that it is rapidly spreading in Central Valley vernal pools. Cal-IPC Rating: Moderate (contributed by Mary Ann Machi)

[www.cabidigitallibrary.org] Europe, Morocco native, Invasive: G. declinata is a perennial grass associated with shallow water. It is native throughout Europe and in Morocco. It has been introduced to, and is invasive in, North America, Australia and New Zealand. In California, G. declinata has invaded deep vernal pools, swales, ditches and stock ponds, and is reported to be rapidly spreading in California's Central Valley (Cal-IPC, 2012). The invasion has led to a degradation of vernal pool ecosystems, the habitat of many federal and state protected endangered and threatened species (Gerlach et al., 2009), and has also become a problem in rice plantations in Louisiana. (contributed by Mary Ann Machi)


Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals. [web application]. 2023. Berkeley, California: The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 11/28/2023).