Glyceria canadensis (Michx.) Trin.
Family: Poaceae
Rattlesnake Manna Grass,  more...
[Briza canadensis ,  more]
Glyceria canadensis image

Plants perennial. Culms 60-150 cm tall, 2.5-5 mm thick, erect or the bases decumbent. Sheaths retrorsely scabridulous to scabrous, keeled; ligules 2-6 mm; blades 8-36 cm long, 3-8 mm wide, abaxial surfaces smooth or scabrous, adaxial surfaces scabridulous to scabrous. Panicles 10-30 cm long, 10-20 cm wide, pyramidal, open, nodding; branches 7-20 cm, lax, divergent, often drooping, with 15-60+ spikelets; pedicels 2.5-9 mm. Spikelets 3-8 mm long, (2.5)3-5 mm wide, laterally compressed, oval in side view, with 2-10 florets. Glumes narrowing from midlength or above to the broadly (> 45°) acute or rounded apices, 1-veined, veins terminating below the apices; lower glumes 0.6-2.4 mm, ovate to rectangular; upper glumes 1.5-2.5 mm, lanceolate; rachilla internodes 0.2-0.5 mm; lemmas 1.8-4 mm, ovate in dorsal view, 5-7-veined, veins evident but not raised distally, smooth over and between the veins, apices acute, prow-shaped; paleas 0.1-0.8 mm shorter than lemmas, lengths 1.5-1.8 times widths, almost round in dorsal view, keels well developed, not winged, tips incurved, apices narrowly notched between the keels; anthers 2, 0.4-0.5 mm, dehiscent at maturity. Caryopses 1.5-2 mm.

Glyceria canadensis is an attractive native species that grows in swamps, bogs, lakeshore marshes, and wet woods throughout much of eastern North America, extending from eastern Saskatchewan to Newfoundland, Illinois, and northeastern Tennessee. It is now established in western North America, having been introduced as a weed in cranberry farms. It forms sterile hybrids with G. striata; the hybrids are called G. ×ottawensis Bowden. For further comments, see the description of Glyceria striata.

Culms solitary or few in a tuft, erect, to 1 m; main lvs 3-8 mm wide; ligule 2-6 mm; infl 1-3 dm, diffuse, with drooping branches bearing spikelets mostly toward the tip; spikelets broadly ovate, 4-8 mm, 5-10-fld; glumes scarious-margined, the first lanceolate, 1.6-2.4 mm, the second broadly ovate, 2.1-2.3 mm; lemmas broadly ovate, with visible but not raised veins, 2.9-4 mm, the thin or scarious margins not covering the sides of the round-obovate palea, the acute tip projecting 0.5 mm beyond the palea; stamens 2; 2n=60. Swamps, bogs, and wet woods; Nf. to Minn., s. to N.J. and Ill.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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