Alisma gramineum (Narrow-leaved Water Plantain)

Plant Info
Also known as:
Genus:Alisma
Family:Alismataceae (Water Plantain)
Life cycle:short-lived perennial
Origin:native
Status:
  • State Special Concern
Habitat:sun; wet, sandy soil; shallow water, shores
Bloom season:June - August
Plant height:1 to 20 inches
Wetland Indicator Status:GP: OBL MW: OBL NCNE: OBL
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: 3-petals Cluster type: panicle

[photo of flowers] Stalked flowers are whorled in open clusters on many branches coming off the main stem. Individual flowers are ¼ to 1/3 inch across, 3 pale pink to purplish petals with a spot of yellow-green at the base. In the center are 6 yellow-tipped stamens surrounding a ring of up to 20 green pistils.

[photo of bracts] Behind the flower are 3 green to brown sepals up to about half as long as the petals. At the base of a whorl of flowers are 3 papery bracts shorter than the flower stalks. When plants are under water, flowers are self-pollinating and do not open (cleistogamous).

Leaves and stems: Leaf attachment: basal Leaf type: simple

[photo of emersed leaves] Plants are aquatic, growing in shallow water, but also on shores or becoming land-locked when water recedes. Leaves can take on different forms depending on the water level—submersed, floating or emersed—but all are in a basal rosette. Submersed and floating leaves are thin, ribbon-like, up to 3 feet long, up to about ½ inch wide, and stalkless. Emersed leaves are long-stalked with a lance-linear to narrowly lance-elliptic blade up to about 2½ inches long and ½ inch wide. Flowering stems are erect and smooth.

Fruit: Fruit type: seed_without_plume

[photo of fruit] Fruit is a ring of seeds 1/8 to ¼ inch in diameter that turns from green to brown as seeds mature. Seeds are 1.8 to 2.7 mm long, oval to round, with a pair of shallow grooves flanking a ridge along the outer edge, and a curved tip on the inner edge, remains of the style forming a short, erect beak.

Notes:

There are 3 species of Water-plantain in Minnesota, Alisma gramineum being the least common. According to the DNR, aquatic plant surveys conducted at over 2,000 lakes over the past 20+ years have only located 16 populations of this species, none of the few recorded pre-1960s have been relocated, and it is not expected many more will be found. The species is at risk from habitat degradation from a variety of sources, including pollution, recreational activities, shoreline erosion and agricultural run-off. Alisma gramineum was listed as a Special Concern species in 2013.

It is distinguished from the other Alisma species in Minnesota by its narrower leaves, pinkish flowers, and ribbon-like leaves when submersed (note: the aquarium plant database Barr Report has an image of submersed leaves). A. subcordatum and A. triviale both have much larger leaf blades (to 7 inches long, 3 inches wide), lack different submersed leaves even when growing in shallow water, and have consistently white flowers. Water-plantain flowers are also similar to Arrowhead, but Arrowhead flowers are much larger—½ to 1 inch across.

Native Plant Nurseries, Restoration and Landscaping Services ↓

Map of native plant resources in the upper midwest

  • Natural Shore Technologies - Using science to improve land and water
  • Minnesota Native Landscapes - Your Ecological Problem Solvers
  • Spangle Creek Labs - Native orchids, lab propagated
  • Prairie Restorations - Bringing people together with the land
  • Landscape Alternatives

More photos

Photos by Peter M. Dziuk taken in North Dakota.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Krista Espelien - Lake Minnetonka Regional Park
on: 2022-09-02 17:45:06

Plant found submerged near public boat access.

Posted by: K Chayka
on: 2022-09-02 18:23:47

Krista, I would have to see it to believe it.

Post a comment

Note: All comments are moderated before posting to keep the spammers out. An email address is required, but will not be posted—it will only be used for information exchange between the 2 of us (if needed) and will never be given to a 3rd party without your express permission.

For info on subjects other than plant identification (gardening, invasive species control, edible plants, etc.), please check the links and invasive species pages for additional resources.



(required)




Note: Comments or information about plants outside of Minnesota and neighboring states may not be posted because I’d like to keep the focus of this web site centered on Minnesota. Thanks for your understanding.