Linaria canadensis (Old-field Toadflax)

Plant Info
Also known as: Blue Toadflax, Canada Toadflax
Genus:Linaria
Family:Plantaginaceae (Plantain)
Life cycle:annual, biennial
Origin:native
Habitat:sun; dry sandy soil, prairies, roadsides
Bloom season:May - July
Plant height:4 to 20 inches
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: irregular Cluster type: raceme

[photo of flowers] Flowers are in a spike-like raceme at the top of the stem that elongates up to 8 inches. Individual flowers average about 1/3 inch long, irregular with an upper lip divided into 2 erect rounded lobes, and a lower lip with 3 rounded lobes. Flower color is blue to blue-violet, with a 2-humped white spot at the base of the lower lip. There is usually 1 spike on a stem, but a plant may have multiple stems.

Leaves and stem: Leaf attachment: alternate Leaf attachment: opposite Leaf type: simple

[photo of leaves] Leaves are 1 to 1½ inches long and very narrow—not more than 1/8 inch wide, toothless, hairless, with pointed tips and no leaf stalk. They are alternately attached and narrower on flowering stems, but oppositely attached and broader on the shorter non-flowering stems. The main stem is smooth and slender, green to reddish brown.

Notes:

With its small flowers and foliage and slender stems, it is easy to miss unless there is a clump of plants together. This species frequently goes by Nuttallanthus canadensis but the accepted name in Minnesota is Linaria canadensis. Formerly in the figwort family (Scrophulariaceae) is has been reassigned to the plantain family (Plantaginaceae).

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More photos

Photos by K. Chayka taken at Wild River State Park, Chisago County.

Comments

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

Posted by: Rick - cass county
on: 2014-09-25 10:42:46

Found something extremly similar to these growing in dense shade next to some ferns by Longville, MN. But the ones I found are different colors, violet, white and yellow and have only one flower at the top of the stem.

Posted by: K. Chayka
on: 2014-09-26 18:15:35

Rick, the flower sounds like Viola tricolor, a.k.a Johnny jump-up.

Posted by: Jason - Marine on St. Croix
on: 2015-06-01 14:20:49

We found some Linaria canadensis today in Andover, Anoka County. First time I have ever seen this in the field or anywhere for that matter. Sandy, south facing exposed bank.

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