Glyceria ×occidentalis
Glyceria elata
northwestern manna grass, western manna grass
fowl manna grass, tall mannagrass
60-160 cm tall, 2.5-5 mm thick, erect or decumbent and rooting from the lower nodes.
75-150 cm tall, 2.5-8 mm thick, spongy, decumbent and rooting at the lower nodes.
smooth to scabridulous, keeled, sometimes weakly so;
ligules 7-12 mm;
blades 20-30 cm long, (2.5)4-12 mm wide, adaxial surfaces scabridulous, occasionally papillose.
scabridulous or hirtellous, not or weakly keeled;
ligules 2.5-4(6) mm, truncate to acute, erose, puberulent;
blades 19-40+ mm long, 6-12(15) mm wide, abaxial surfaces smooth or scabridulous, adaxial surfaces usually scabrous, sometimes scabridulous.
20-50 cm long, 2-15 cm wide, usually narrow, open at anthesis;
branches 4.5-18 cm, somewhat lax, usually ascending, strongly divergent at anthesis, with 2-8 spikelets, pedicels 1.5-8 mm.
15-30 cm long, 12-30 cm wide, pyramidal, open;
branches 12-17 cm, divergent to drooping, lax, with 30-50+ spikelets;
pedicels 0.3-5 mm.
13-23 mm long, 1.5-3.5 mm wide, cylindrical and terete, except at anthesis when slightly laterally compressed, rectangular in side view, with 6-13 florets.
3-6 mm long, 1.5-2.8 mm wide, laterally compressed, oval in side view, with 3-4(6) florets.
acute to obtuse;
lower glumes 1.1-2.8 mm;
upper glumes 2.9-3.7 mm, about twice as long as the lower glumes;
rachilla internodes 1-2.8 mm;
lemmas 4.5-5.9 mm, scabridulous, midveins extending to within 0.1 mm of the apical margins, apices acute, usually slightly lobed or irregularly crenate;
paleas usually shorter than or equaling the lemmas, sometimes slightly longer, keels winged, apices shallowly notched to slightly bifid, teeth to 0.2 mm, parallel;
anthers 2, 0.6-1.6 mm.
1-1.5(2) times longer than wide, narrowing beyond midlength, veins terminating below the apical margins, apices obtuse to rounded;
lower glumes 0.7-1.5 mm;
upper glumes 1-1.5 mm;
rachilla internodes 0.5-0.6 mm;
lemmas 1.7-2.2 mm, oval in dorsal view, 5-7-veined, veins raised throughout, scabridulous, apices rounded, prow-shaped;
paleas subequal to or often slightly longer than the lemmas, lengths 2.4-3 times widths, oval in dorsal view, keels not winged, tips pointing towards each other, apices narrowly notched between the keels;
anthers 2, 0.5-0.8 mm.
0.8-1.5 mm long, 0.5-0.7 mm wide;
hila as long as the caryopses.
= 40.
= 20.
Glyceria ×occidentalis
Glyceria elata
Glyceria ×occidentalis has hitherto been considered an uncommon native species that grows along lakes, ponds, and streams, and in marshy areas of western North America. It differs from other species in the region primarily in its longer lemmas and anthers. Studies of chloroplast DNA in western North American species of Glyceria demonstrated that, contrary to C.L. Hitchcock's (1969) conclusion, G. fluitans is present in western North America, and that all specimens being identified as G. ×occidentalis had cpDNA resembling that of G. leptostachya or G. fluitans; there was no distinctive G. ×occidentalis cpDNA (Whipple et al. [in press]). This strongly suggests that G. ×occidentalis is a series of reciprocal hybids, and probably backcrosses, between G. fluitans and G. leptostachya. As the key indicates, G. ×occidentalis is intermediate between its two putative parents. The cpDNA study also confirmed that G. declinata is distinct from G. ×occidentalis (see discussion under that species).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Glyceria elata grows in wet meadows and shady moist woods, from British Columbia east to Alberta and south to California and New Mexico. It is not known from Mexico. The anomalous record from Georgia may represent an inadvertent introduction. It is very similar to, and sometimes confused with, G. striata, but the two sometimes grow together and show no evidence of hybridization. Their differences in growth habit and stature are evident in the field. Molecular data (Whipple et al. [in press]) confirm that G. elata and G. striata are distinct, closely related entities.
Glyceria elata is also sometimes confused with G. grandis. It differs in having rounded glumes with veins that terminate below the apices, more readily disarticulating florets, and greener lemmas with more prow-shaped apices, as well as in having paleal keel tips that point towards each other. In its overall aspect, it also resembles G. pulchella, but has somewhat more lax panicle branches than that species, in addition to smaller spikelets and florets.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
- Local floras: BC, CA, OR, WA
- Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
