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Glyceria canadensis

©Utah State University

Glyceria maxima

©Utah State University

Glyceria leptostachya

©Utah State University

Glyceria canadensis

©Timothy M. Jones

Vegetative Morphology

 
Plants usually perennial, rarely annual; rhizomatous.
Culms (10)20-250 cm, erect or decumbent, freely rooting at the lower nodes, not cormous based.
Sheaths closed for at least 3/4 their length, often almost entirely closed.
Ligules scarious, erose to lacerate.
Blades flat or folded.

Reproductive Morphology

 
Inflorescences terminal, usually panicles, sometimes racemes in depauperate specimens, branches appressed to divergent or reflexed.
Spikelets cylindrical and terete or oval and laterally compressed, with 2-16 florets, terminal floret in each spikelet sterile, reduced.
Disarticulation above the glumes, below the florets.
Glumes much smaller than to equaling the adjacent lemmas, 1-veined, obtuse or acute, often erose.
Lower glumes 0.5-4.5 mm.
Upper glumes 0.6-7 mm.
Calluses glabrous.
Lemmas membranous to thinly coriaceous, rounded over the back, smooth or scabrous, glabrous or hairy, hairs to about 0.1 mm, 5-11-veined, veins usually evident, often prominent and ridged, not or scarcely converging distally, apical margins hyaline, sometimes with a purplish band below the hyaline portion, apices acute to rounded or truncate, entire, erose, or irregularly lobed.
Paleas from shorter than to longer than the lemmas, keeled, keels sometimes winged.
Lodicules thick, truncate, not winged.
Anthers (1)2-3.
Ovaries glabrous.
Styles 2-branched, branches divergent to recurved, plumose distally.

Species Distribution Maps

Glyceria grandis Glyceria nubigena Glyceria borealis Glyceria fluitans
Glyceria alnasteretum Glyceria pulchella Glyceria septentrionalis Glyceria declinata
Glyceria maxima Glyceria striata Glyceria acutiflora Glyceria notata
Glyceria obtusa Glyceria elata Glyceria leptostachya
Glyceria melicaria Glyceria canadensis Glyceria x occidentalis

Chromosome Number(s)

x = 10

Additional Notes

Name from the Greek glukeros, 'sweet', the caryopses of the type species being sweet.

Glyceria includes approximately 35 species, all of which grow in wet areas. All but five species are native to the Northern Hemisphere. The genus is represented in the Flora region by 16 species and 3 hybrids. One additional European species, Glyceria notata, is included in this treatment because it has been reported to be present in the region.

All native species of Glyceria are palatable to livestock. They are rarely sufficiently abundant to be important forage species. Some grow in areas that are soon degraded by grazing. G. maxima can cause cyanide poisoning in cattle. Species in sects. Striatae and Hydropoa have potential as ornamentals.

Glyceria resembles Puccinellia in the structure of its spikelets and its preference for wet habitats; it differs in its inability to tolerate highly alkaline soils, and its usually more flexuous panicle branches, closed leaf sheaths, and single-veined upper glumes. Some species are apt to be confused with Torreyochloa pallida, another species associated with wet habitats but one that, like Puccinellia, has open leaf sheaths.

Glyceria includes several species that, in the herbarium, appear to intergrade. In some cases, the distinctions between such taxa are more evident in the field, particularly when they are sympatric. Recognition of such taxa at the specific level is merited unless it can be shown that all the distinctions between them are inherited as a group.

The three named North American hybrids are Glyceria xgatineauensis Bowden, G. xottawensis Bowden, and G. xoccidentalis (Piper) J.C.Nelson. The first two were named as hybrids; they are not included in the key and are mentioned only briefly in the descriptions. Glyceria xoccidentalis has hitherto been treated as a species.  It is included in the key and provided with a full description.

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Name/Synonymy Publication Info

Glyceria R. Br., Prodr. 179 (1810), nom. cons. TYPE: Glyceria fluitans (L.) R. Br.

Nevroloma Raf., J. Phys. Chim. Hist. Nat. Arts 89:106 (1819). TYPE: Nevroloma canadensis (Michx.) Raf. [=Glyceria canadensis (Michx.) Trin.].

Hemibromus Steudel, Syn. pl. glumac. 1:317 (1854). TYPE: Hemibromus japonicus Steudel [=Glyceria acutiflora Torrey].

Porroteranthe Steudel, Syn. pl. glumac. 1:287 (1854). TYPE: Porroteranthe drummondii Steudel [=Glyceria fluitans (L.) R. Br.].

Treatment from

M.E. Barkworth and L.K. Anderton. Glyceria in Flora of North America, volume 24. In prep. Oxford University Press.

Fact Sheet Developed By

Pedro Oñativia Lake © 2006.