Glyceria maxima
Poaceae tribe Meliceae
English watergrass, giant mannagrass, glycerie aquatique, reed manna grass, rough mannagrass, tall glyceria, tall mannagrass
60-250 cm tall, 6-12 mm thick, erect.
annual, not woody, not branching above the base;
internodes hollow.
scabridulous, keeled;
ligules 1.2-6 mm, rounded or with a central point, ligules of the lower leaves thick, stiff, and opaque, ligules of the upper leaves thinner and translucent;
blades 30-60 cm long, 6-20 mm wide, both surfaces smooth or adaxial surfaces scabridulous.
closed for their whole length or almost so;
collars without tufts of hair on the sides;
auricles sometimes present;
ligules hyaline, glabrous, often lacerate, occasionally ciliate, those of the lower and upper cauline leaves usually similar;
pseudopetioles absent;
blades linear to narrowly lanceolate, venation parallel, cross venation sometimes evident;
cross sections non-Kranz, without arm or fusoid cells;
epidermes without microhairs, sometimes papillate.
15-45 cm long, to 30 cm wide, open;
branches 8-20 cm, lax, strongly divergent or drooping at maturity, scabridulous, primary branches with 50+ spikelets;
pedicels 0.8-10 mm.
terminal panicles or racemes;
disarticulation above the glumes and beneath the florets or below the glumes.
5-12 mm long, 2-3.5 mm wide, somewhat laterally compressed, oval in side view, with 4-10 florets.
2.5-60 mm, not viviparous, slightly to strongly laterally compressed, with 1-30 florets, proximal florets bisexual, distal 1-3 florets usually sterile, sometimes pistillate, sometimes reduced and amalgamated into a knob- or club-shaped rudiment;
rachillas prolonged beyond the base of the distal floret.
unequal, usually the midvein of 1 or both reaching to the apices;
lower glumes 2-3 mm;
upper glumes 3-4 mm, longer than wide;
rachilla internodes 0.5-1 mm;
lemmas 3-4 mm, 7-veined, veins scabridulous, apices broadly acute to rounded, slightly prow-shaped;
paleas subequal to the lemmas, lengths more than 3 times widths, keels not winged, ciliate, tips not strongly incurved, curved to broadly notched between the keels;
anthers 3, (1)1.2-2 mm.
exceeded by the distal florets, shorter than to longer than the adjacent lemmas, mostly membranous, scarious distally, 1-11-veined, apices usually rounded to acute;
florets laterally or dorsally compressed;
calluses blunt, glabrous or with hairs;
lemmas of sexual florets rectangular or ovate, mostly membranous, scarious distally, often with a purplish band adjacent to the scarious apices, (4)5-15-veined, veins not converging distally, often prominent, unawned or awned, awns not branched, apices entire to bilobed or bifid, awns straight, subterminal or from the sinuses;
paleas from shorter than to longer than the lemmas, similar in texture, 2-veined, veins keeled, sometimes winged;
lodicules 2, fleshy, usually connate into a single structure, without a membranous wing, truncate, not ciliate, not or scarcely veined;
anthers 1, 2, or 3;
ovaries glabrous;
styles 2-branched, bases persistent, branches plumose distally.
1.5-2 mm.
ovoid to ellipsoid, longitudinally grooved or not;
hila usually linear;
embryos less than 1/3 as long as the caryopses.
= (8)9, 10.
= 60.
Glyceria maxima
Poaceae tribe Meliceae
Glyceria maxima is native to Eurasia. It grows in wet areas, including shallow water, at scattered locations in the flora region. It is an excellent fodder grass, and may have been planted deliberately at one time (Dore and McNeill 1980). At some sites, the species appears to be spreading, largely vegetatively. It is easily confused with large specimens of G. grandis, but differs in its firmer, more prow-tipped lemmas as well as its larger lemmas and usually larger anthers.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
There are approximately 130 species and 8 or 9 genera in the Meliceae. Four of the genera are monotypic. Melica and Glyceria, the two largest genera, are well represented in North America. Pleuropogon and Schizachne are primarily North American, but extend into eastern Asia.
Molecular studies (e.g., Soreng and Davis 2000; Grass Phylogeny Working Group 2001) show the tribe to be monophyletic and somewhat basal within the Pooideae. Members of the tribe are most easily recognized by the combination of closed leaf sheaths, scarious lemma apices, and non-converging lemma veins. The tribe also differs from other tribes in the Pooideae in having 2 unwinged lodicules that are usually connate into a single structure, and a base chromosome number of 9 or 10. Catabrosa and Briza, whose inclusion in the tribe was suggested by the preliminary results of Mejia-Saules and Bisby (2000), have more membranous lemma margins and free, winged lodicules. Briza also has open leaf sheaths and more convergent lemma veins. Their inclusion is not supported by the molecular data.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Calluses hairy; lemmas awned, awns 8-15 mm long, twisted, divergent to slightly geniculate | Schizachne |
1. Calluses glabrous; lemmas unawned or awned, awns to 12 mm long, straight. | → 2 |
2. Inflorescences racemes; palea keels winged, the wings notched and awned | Pleuropogon |
2. Inflorescences usually panicles, racemes in depauperate specimens; palea keels not winged or the wings entire and unawned. | → 3 |
3. Lower glumes 1-veined, 0.3-4.5 mm long; disarticulation always above the glumes; lemmas unawned, never with hairs more than 1 mm long; culms never with cormous bases; distal florets in the spikelets sometimes reduced, not forming a morphologically distinct rudiment; plants of wet meadows and streamsides | Glyceria |
3. Lower glumes 1-9-veined, 2-16 mm long; disarticulation above or below the glumes; lemmas sometimes awned, sometimes with hairs longer than 1 mm; culms sometimes with cormous bases; distal florets in the spikelets often forming a morphologically distinct rudiment; plants of drier or well drained habitats | Melica |
BC
WA
Flora NW
Go Botany
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
