Calamagrostis canadensis (Canada Bluejoint)
|Also known as:||Bluejoint Reedgrass|
|Habitat:||part shade, sun; moist to wet; shores, swales, wet meadows, marshes, bogs|
|Fruiting season:||July - August|
|Plant height:||2 to 5 feet|
|Wetland Indicator Status:||GP: FACW MW: OBL NCNE: OBL|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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A panicle at the tip of the stem 4 to 10 inches long, pyramidal in outline at flowering time with mostly spreading branches. Branches are up to 3 inches long and compound, the secondary branchlets appressed to loosely spreading, the spikelets (flower clusters) loosely arranged on the tip half or so of a branch. Spikelets are lance-elliptic in outline, somewhat compressed, 2 to 6 mm (to ¼ inch) long, light green, with a single floret.
At the base of a spikelet is a pair of bracts (glumes), both awnless, slightly spreading, 1-veined, smooth to rough-textured with straight or bent hair-like teeth, lance-elliptic with a pointed tip, the lower glume 2 to 6 mm long, the upper glume more or less as long. Florets are surrounded by a pair of bracts (lemma and palea), both thin, pale, pointed at the tip, the lemma 5-veined, ¾ to 1 times as long as the upper glume, with a slender, straight to slightly bent awn arising from about midway up the back that may extend slightly beyond the tip of the glumes; the palea is somewhat shorter than the lemma and 2-veined. The thickened base of the floret (callus) is densely covered in straight, white hairs that are half to slightly longer than the floret but may be hidden by the glumes.
Leaves and stems:
Leaves are basal and alternate, 2 to 10 mm (to 3/8 inch) wide, 6 to 20 inches long, hairless but rough on both surfaces and along the edges, mostly flat, green to blue-green, rarely with a few scattered hairs. The sheath is hairless but usually rough-textured. The ligule (membrane where the leaf joins the sheath) is 3 to 10 mm long, ragged or shredded along the tip edge and lacks a fringe of hairs. Nodes are smooth.
Stems are leafy, hairless, mostly erect, multiple from the base, and usually branched above the base. Clumps are formed from a mix of flowering and vegetative shoots, the dead stems and leaves persisting and forming tussocks. Colonies may also form from elongated rhizomes.
Canada Bluejoint is a common native grass, found in a variety of moist to wet places all across Minnesota as well as much of North America. It would probably be the dominant grass in many wetlands were it not for invasive Reed Canary Grass. Canada Bluejoint is distinguished by its moist to wet habitat, branched and leafy stems, flat leaves to 10 mm wide, long hairless ligule split or shredded along the top edge, terminal panicle with branches either spreading (flowering) or erect/ascending to nodding (fruiting), with single-flowered spikelets 2 to 6 mm long, glumes as long as or somewhat longer than the floret, lemmas with long hairs on the callus and a short awn arising from about the middle of the lemma, though the awn may not be readily distinguish from the callus hairs. C. canadensis can be rather variable, with 3 recognized varieties, all of which have been recorded in Minnesota. There are some conflicting descriptions of these vars, which is likely caused by the general variability of this species, but most likely:
- var. macouniana has the smallest spikelets, 2 to 3 mm long, glumes are not conspicuously keeled and are usually smooth or have a few straight teeth along the midvein, lemmas as long as or shorter than the glumes, callus hairs as long as or shorter than the lemma
- var. langsdorffii, the least common, has the largest spikelets, 4 to 6 mm long, glumes rough-textured throughout with bent hair-like teeth along the keel, lemmas shorter than the glumes, callus hairs usually as long as or slightly longer than the lemma
- var. canadensis, the most common and the most variable, has spikelets 2.5 to 4 mm long, glumes obviously keeled or not, smooth or rough or rough only along the keel with straight hair-like teeth, lemmas as long as or slightly shorter than the glumes, callus hairs more or less as long as the lemma
Canada Bluejoint is most similar to the related Calamagrostis stricta subsp. inexpansa, which is a sightly smaller plant, the widest leaves rarely more than 5 mm, the panicle is more compact and spike-like, spikelets are arranged all along a panicle branch not just towards the tip, lemma awns arise from the lower third of the lemma and are often bent. Also somewhat similar is Sand Reed Grass (Calamovilfa longifolia), which also has a narrow panicle of single-flowered spikelets and hairy calluses, but its ligule is a short fringe of hairs with longer hairs at the tip of the sheath, and it prefers dry sandy soil.
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- Canada Bluejoint plant
- Canada Bluejoint plants
- Canada Bluejoint plants
- garden-grown Canada Bluejoint
- a colony of Canada Bluejoint
- dead foliage persists through winter
- blue-green shoots emerging in spring
- close-up of mature spikelets
Photos by K. Chayka taken in Anoka and Ramsey counties. Photos by Peter M. Dziuk taken in Anoka, Becker, Carlton, and Washington counties.
Have you seen this plant in Minnesota, or have any other comments about it?