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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: Geyer waterplantain

Synonyms and Other Names: Narrowleaf water-plantain, narrow-leaved water-plantain, ribbonleaf water-plantain, ribbon-leaved water-plantain

Taxonomy: available through www.itis.gov

Identification: Alisma gramineum is a small aquatic plant in the water-plantain family. It grows in mud or submerged in shallow fresh or brackish water in marshy areas. It is distinguished from other species in Alisma by its narrow leaves, wide umbels, small flowers with whitish-purple corolla (petals), concurrent undulate scapes (stalks), and three-ridged brown fruits (Hendricks 1957) (see Hendricks 1957 for keys to the species of Alisma). When fruiting, A. gramineum is recognized by tricarinate (three-ridged) achenes (one-seeded fruit) as opposed to bicarinate (two-ridged) achenes of A. triviale and A. subcordatum (Countryman 1968).

Size: Stem is about 50 cm long, leaves up to 100 cm long and 2 cm wide, open flowers 4-8 mm across (Smith 2018).

Native Range: Widespread in temperate and subarctic North American, Europe, and Asia (Hendricks 1957). Extends from central Asia through Europe to Holland, Belgium, France, and the United Kingdom (Lousley 1957). Reported from much of Canada (British Columbia to Quebec) and the Western United States plus New York, and Vermont (BONAP 2015).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Alisma gramineum is a perennial aquatic forb that prefers stagnant or slow-flowing waters of littoral zones with fluctuating water levels (Moravcová et al. 2001). It roots in shallow water (up to 1.6 m) and prefers sandy substrate, typically alkaline (7.5-9.6 pH) (Smith 2018, Les 2020). It is suited for submerged growth and sometimes sets flowers and fruits under water, however the flowers only bloom above the water’s surface (Moravcová et al. 2001). When flowers are submerged, they are closed and self-pollinate (cleistogamous), and it reproduces by seeds which requires cold stratification and germinate best at 25 °C (Moravcová et al. 2001). In the United States, flowers and fruits are present usually between July and September (Smith 2018).

Ducks (Anas spp.) will eat the achenes (fruits) of A. gramineum (Les 2020).

Means of Introduction: Likely dispersed by waterfowl. Seeds are buoyant for up to 128 hours, adding to the seed bank in the sediment upon sinking (Les 2020).

Status: Established as a native transplant in Virginia.

Impact of Introduction: Established populations of Alisma gramineum have reduced wave energies, causing local sedimentation rates to increase (Vermaat et al. 2000).

Remarks: Specimen vouchers: (George Mason University: GMUF 0036308, VPI 0009888, WILLI 68311) (Virginia Polytechnic Institute and State University: VPI 0009887, WILLI 76608)

References: (click for full references)

Countryman, W.D., 1968. Alisma gramineum in Vermont. Rhodora, 70(784), pp.577-579.

Hendricks, A.J., 1957. A Revision of the Genus Alisma (Dill.) L. The American Midland Naturalist, 58(2), pp.470-493.

Kartesz, J.T., The Biota of North America Program (BONAP). 2015. Taxonomic Data Center. (http://www.bonap.net/tdc). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

Les, D.H., 2020. Aquatic monocotyledons of North America: ecology, life history, and systematics. CRC Press, Boca Raton, FL.

Lousley, J. E., 1957. Alisma gramineum in Britain. Proc. Bot. Soc. Brit. Isles 2: 346-353. pl. 6.

Moravcová, L., Zákravský, P. and Hroudová, Z., 2001. Germination and seedling establishment in Alisma gramineum, A. plantago-aquatica and A. lanceolatum under different environmental conditions. Folia Geobotanica, 36, pp.131-146.

Rogers, G.K., 1983. The genera of Alismataceae in the southeastern United States. Journal of the Arnold Arboretum, 64(3), pp.383-420.

Smith, W.R., 2018. Minnesota Department of Natural Resources: Rare Species Guide. https://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=PMALI01010 (Accessed: 12/21/2023)

Vermaat, J.E., L. Santamaria, and P.J. Roos. 2000. Water flow across and sediment trapping in submerged macrophyte beds of contrasting growth form. Archiv für Hydrobiologie 148(4):549-562. https://www.academia.edu/download/84011738/Water_flow_across_and_sediment_trapping_20220412-1-1xrea1j.pdf.

Author: Reaver, K.M.

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.