Elymus villosus (Silky Wild Rye)

Plant Info
Also known as: Hairy Wild Rye, Downy Wild Rye
Genus:Elymus
Family:Poaceae (Grass)
Life cycle:perennial
Origin:native
Habitat:part shade, sun; moist to dry sandy or rocky soil; woods, floodplain forest, river banks, ravines, wooded slopes, rock outcrops
Fruiting season:July - August
Plant height:16 to 40 inches
Wetland Indicator Status:GP: FACU MW: FACU NCNE: FACU
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: indistinct Cluster type: spike

[photo of spike] A single thick spike 1½ to 5 inches long at the tip of the stem, usually nodding and usually with 2 ascending spikelets (flower clusters) at each node, rarely 1 or 3. Each spikelet is 7 to 12 mm long (excluding awns) and usually has a single floret, occasionally 2, rarely 3; the uppermost floret may be sterile. Color is commonly light green at flowering time.

[close-up of spikelets] At the base of a spikelet is a pair of bracts (glumes), both firm, usually sparsely stiff-hairy though may become hairless, 2 or 3-veined, narrowly oblong-elliptic tapering at the tip to a straight awn about as long as the body, .3 to .8 mm wide, 12 to 25 mm (to 1 inch) long including the awn, the base somewhat hardened, slightly narrowed or not, straight to slightly bowed, the pair of glumes spreading away from the stem. Florets are surrounded by a pair of bracts (lemma and palea), the lemma hairy, 5 to 7-veined, the body 6 to 9 mm long with a straight awn 9 to 33 mm long; the palea is about as long as the lemma, 2-veined, hairless.

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

[photo of leaf hairs] The 4 to 8 leaves are alternate, up to 8 inches long, 3 to 12 mm (to ~½ inch) wide, mostly flat, arching to floppy, fairly evenly distributed along the stem, covered in short silky hairs on the upper surface, sometimes with longer hairs on the veins. Color is typically dark green.

[photo of sheath, ligule and node] The sheath is sparsely to moderately hairy, sometimes just fringed with hairs or becoming hairless, and has a pair of small brown to purplish lobes (auricles) at the apex. The ligule (membrane where the leaf joins the sheath) is less than 1 mm long, more or less straight across, and lacks a fringe of hairs. Nodes are hairless and may or may not be hidden in the sheaths. Stems are unbranched, smooth, erect to ascending, multiple from the base, forming loose to dense clumps.

Fruit: Fruit type: seed without plume

[photo of glumes and mature florets] The awns typically remain relatively straight as spikelets mature, all turning a light brown when dry. Florets drop off individually as they mature, leaving the glumes behind on the stalk. Grains (seeds) are elliptic, purplish-brown, and have a tuft of white to light brown hairs at the tip.

Notes:

There are 10 Elymus species in Minnesota (not counting vars/subspecies); Silky Wild Rye is mostly found in the southern half of the state with scattered populations farther north. It is found in sandy or gravelly soils, usually shaded in wooded areas but occasionally in open, sunnier rock outcrops or meadows.

Elymus villosus is distinguished by its hairy sheaths, leaves, glumes and lemmas, glumes less than 1 mm wide, nodding spike with straight awns, and usually 1-flowered spikelets. There are 2 forms that are considered vars in some references, but are not recognized in Minnesota: f. arkansanus is nearly hairless and f. villosus is as described above. Both should have the nodding spike, single-flowered spikelets, narrow glumes and straight awns.

There are several Elymus species with nodding spikes that may be confused with E. villosus, all of which are less hairy and more consistently have 2 or more florets per spikelet. Interrupted Wild Rye (Elymus diversiglumis) also has glumes that are distinctly unequal in length and less than .5 mm wide; Wiegand's Wild Rye (Elymus wiegandii) is taller (to 6 ft) and leafier (9 to 16 leaves), with a larger spike that is distinctly drooping from near the base; Canada Wild Rye (Elymus canadensis) has widest glumes at least 1 mm wide; Riverbank Wild Rye (Elymus riparius) usually has 8 to 10 leaves where E. villosus has 4 to 8.

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More photos

Photos by K. Chayka taken in her garden. Photos by Peter M. Dziuk taken in Dakota, Fillmore and Renville counties, and his garden.

Comments

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

Posted by: Stephen L Thomforde - Bloomington
on: 2020-02-04 09:31:24

Hey Guys, This is a beautiful grass indeed. I see it often as the last survivor of extreme disturbance, too much shade, afforestation, the catastrophic state. Anyways, just an interesting observation, it's only a story, but a pretty darn good story. As scientist, in complex systems, telling stories is as good as it gets. Right? Hope you are both well. ST~

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