Glyceria canadensis var. laxa
Glyceria canadensis
limp mannagrass
Canada mannagrass, Canadian mannagrass, rattlesnake manna grass, rattlesnake-grass
60-150 cm tall, 2.5-5 mm thick, erect or the bases decumbent.
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.
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.
3-5 mm, with (2)3-5 florets.
3-8 mm long, (2.5)3-5 mm wide, laterally compressed, oval in side view, with 2-10 florets.
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.
0.6-1.3 mm;
upper glumes 1.5-2.3 mm, usually rounded, sometimes acute;
lemmas 1.8-2.5 mm.
1.5-2 mm.
= 60.
Glyceria canadensis var. laxa
Glyceria canadensis
Glyceria canadensis var. laxa grows in swamps, bogs, and wet woods, primarily along the eastern seaboard of North America from Nova Scotia to northeastern Tennessee. It is sometimes treated as a hybrid, G. xlaxa (Scribn.) Scribn., but several specimens have dehiscent anthers and well-formed caryopses, indicating that they are not hybrids. The report of 2n = 30 is based on counts for G. xottawaensis.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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. xottawensis Bowden. For further comments, see p. 77.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Lemmas 2.4-4 mm long; spikelets 5-8 mm long, with 4-10 florets; lower glumes 1.6-2.4 mm long; upper glumes acute | var. canadensis |
1. Lemmas 1.8-2.5 mm long; spikelets 3-5 mm long, with 2-5 florets; lower glumes 0.6-1.3 mm long; upper glumes usually rounded, sometimes acute | var. laxa |
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