Elymus canadensis (Canada Wild Rye)
|Also known as:||Nodding Wild Rye, Great Plains Wild Rye|
|Habitat:||part shade, sun; moist to dry; sandy prairies, dunes, woodland edges, roadsides|
|Fruiting season:||July - August|
|Plant height:||1 to 5 feet|
|Wetland Indicator Status:||GP: FACU MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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A single, nodding to drooping, thick spike 3 to 10 inches long at the tip of the stem, with a group of 2 or 3 erect to ascending spikelets (flower clusters) at each node. Each spikelet is 12 to 20 mm long (excluding awns) and usually has 3 to 5 florets, occasionally more or less; the uppermost floret may be sterile. Color is commonly blue-green at flowering time.
At the base of a spikelet is a pair of bracts (glumes), both firm, hairless, minutely toothed along the edges, 3 to 5-veined, narrowly oblong-elliptic tapering at the tip to a straight awn about as long as the body, .5 to 1.6 mm wide, 11 to 40 mm (to ~1½ inches) long including the awn, the base somewhat hardened, slightly narrowed, more or less straight and not distinctly bowed. Florets are surrounded by a pair of bracts (lemma and palea), the lemma hairless to variously hairy, 5-veined, the body 8 to 15 mm long with a straight awn 15 to 40 mm long; the palea is slightly shorter than the lemma, hairless, 2-veined.
Leaves and stems:
The 4 to 10 leaves are alternate, up to 12 inches long, up to 15 mm (~½ inch) wide, mostly flat, sometimes folded or rolled along the edge, usually hairless, fairly evenly distributed along the stem, and usually ascending but often floppy in the upper half. The underside of the leaf is covered in a waxy bloom (glaucus), giving a bluish tint.
The sheath is usually hairless, sometimes hairy, and has a pair of small brown to purplish lobes (auricles) at the apex. The ligule (membrane where the leaf joins the sheath) is .5 to 1 mm long, more or less straight across, and lacks a fringe of hairs. Nodes are hairless and most are hidden in the sheaths. Stems are unbranched, smooth, erect or the lower stem prostrate then rising at the lower node (geniculate). Stems are single or multiple from the base and form loose to dense clumps.
The awns often bend or curve outward as spikelets mature, all turning a bleached tan when dry. Florets drop off individually as they mature, leaving the glumes behind on the stalk.
There are 10 Elymus species in Minnesota (not counting vars/subspecies), but Canada Wild Rye is the most common native of the bunch in the state and probably the most common native of the genus in North America, present in all but a few states in the southeastern U.S. It is found in a variety of habitats, from dry to moist, usually in sandy or rocky soil. Look for it in prairies, meadows, savannas, dunes, beaches, river and creek banks, bluffs, jack pine stands, open woods, roadsides and railroad rights-of-way. It is commonly used in restoration plantings.
Elymus canadensis is distinguished by its (usually) nodding spike; 2 or 3 spikelets per node; 3 to 5 florets per spikelet, (usually) hairy lemmas; glumes and lemmas both long-awned; both glumes hairless, nearly equal in size, .5 to 1.6 mm wide (widest glumes 1+ mm) and hardened but essentially straight at the base, not bowed; florets drop off above the glumes; plants often strongly glaucus; 4 to 10 leaves (usually 8 or less), firm, hairless, up to about 15 mm wide.
There are at least 3 vars of Elymus canadensis, though they are not universally recognized: var. canadensis is often strongly glaucus, lemmas are usually hairy, distance between spike nodes (internodes) is 4 to 7 mm, where the others are not strongly glaucus, lemmas not usually hairy and internodes are 3 to 4 mm; var. brachystachys awns are also 20 to 30 mm long, glume bases are not hardened or bowed; var. robustus glume bases are often hardened and bowed, lemmas only occasionally hairy, awns 30 to 40 mm long. Though Flora of North America notes all 3 vars may be present in Minnesota, only a handful of collections for var. robustus (from pre-1940) exist and none for var. brachystachys. In all likelihood var. canadensis is the only one currently in MN.
There are several Elymus species with nodding spikes that may be confused with E. canadensis; Interrupted Wild Rye (Elymus diversiglumis) has glumes that are distinctly unequal in length and less than .5 mm wide, leaf nodes that are mostly exposed and is less likely to be glaucous; Silky Wild Rye (Elymus villosus) has hairy glumes, lemmas, sheaths and leaves; Wiegand's Wild Rye (Elymus wiegandii) is a larger plant (to 6ft tall), leafier (9 to 16 leaves), floppy leaves 10 to 20+ mm wide, spikes to 12 inches long all drooping from near the base, widest glumes less than 1 mm wide and may be hairy; Riverbank Wild Rye (Elymus riparius) usually has 2 spikelets per node, 2 or 3 florets per spikelet, widest glumes less than 1 mm wide, and awns are mostly straight even at maturity.
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- Canada Wild Rye plants
- Canada Wild Rye plants
- Canada Wild Rye plants
- late season plant
- blue-green and waxy bloom (glaucus) on back of leaf
- mature spikes
- spikes usually have 2 or 3 spikelets per node, 4 to 7 mm between nodes
Photos by K. Chayka taken in Ramsey County. Photos by Peter M. Dziuk taken in Dakota and Itasca counties.
Have you seen this plant in Minnesota, or have any other comments about it?