Diario del proyecto Aquatic Plants of Minnesota

We are 16 observations away from having 10,000 aquatic plant posts in Minnesota! If you get out in the next few days - your next aquatic plant post may be number 10,000!

Congrats to kemerso21 for posting the 10,000th observation of an aquatic plant in Minnesota! And thanks to everyone who has waded out into the wetlands and waters of our state to photograph and share your aquatic plant observations.

More than 2,500 observers have posted 143 different species - from Minnesota's smallest flowering plants (Wolffia) to our largest flowering plant (Nelumbo lutea). Thanks for appreciating these wonderful plants and for sharing your findings with others.

As you head outside to enjoy the last warm days of autumn, arrowheads (Sagittaria) may be one of the plants you find. There are 6 species of Sagittaria documented in Minnesota and it’s helpful to have photos of leaves, flowers and/or fruits to distinguish them.

Keep an eye out for this rare species:

Hooded arrowhead (Sagittaria calycina var. calycina) is a Threatened Species in Minnesota. It has been found in mucky river and lake floodplains and with low water levels, this is a great year to search for it.

Leaves range from egg shaped to arrow-shaped and may look similar to other Sagittaria species. Several species may grow together at the same site and flowers and fruits can help distinguish species. Look for these features:

1. Hooded arrowhead leaf blades are usually held horizontal to the ground, not vertical like the other species.
2. Flowers may still be present in the fall and are the lower flowers are unique – with a ring of yellow stamens surrounding a bulbous yellow-green center of tiny carpels.
3. Fruits are quite distinctive with thick stalks that curve downward.

If you think you’ve found this species, note that iNaturalist uses this synonym: Sagittaria montevidensis ssp. calycina

For more information on how to identify this plant, see these websites:

MN DNR Rare Species Guide:
https://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=PMALI04040

Minnesota Wildflowers website:
https://www.minnesotawildflowers.info/flower/hooded-arrowhead

Please message mndnr-aquatic-plants if you have any questions about this species.