Thinopyrum ponticum
Thinopyrum intermedium
Eurasian quack grass, rush wheatgrass, tall wheatgrass
intermediate wheatgrass
50-200 cm, glabrous;
lowest internode plus sheath about 3.5 mm thick.
50-115 cm, glabrous or hairy, sometimes hairy only on the nodes;
lowest internode plus sheath 3-5 mm thick.
ciliate on the lower margins;
auricles 0.2-1.5 mm;
ligules 0.3-1.5 mm;
blades 2-6.5 mm wide, generally convolute, adaxial surfaces with 1-8 ribs, ribs rounded, prominent, spinulose, margins usually thinner than the ribs.
mostly glabrous, often ciliate on the margins;
auricles 0.5-1.8 mm;
ligules 0.1-0.8 mm;
blades 2-8 mm wide, flat, abaxial surfaces glabrous, adaxial surfaces usually sparsely strigose, sometimes with hairs of mixed lengths, with 7-30 ribs, ribs not prominent, margins whitish, thicker than the veins.
10-42 cm, erect;
internodes 9-19 mm;
rachises glabrous, not disarticulating at maturity.
8-21 cm, erect or lax;
internodes 7-12 mm;
rachises glabrous or with hairs, scabrous on the edges, particularly distally, not disarticulating at maturity.
13-30 mm, with 6-12 florets;
disarticulation beneath the florets.
11-18 mm, with 3-10 florets;
disarticulation beneath the florets.
oblong, glabrous, 5-9-veined, midveins about equal in length and prominence to the lateral veins, margins about 0.5 mm wide, hyaline, apices truncate;
lower glumes 6.5-10 mm, midveins occasionally scabrous distally;
upper glumes 7-10 mm;
lemmas 9-12 mm, glabrous;
paleas 7.5-11 mm, keeled, keels ciliate;
anthers 4-6 mm.
oblong, glabrous and mostly smooth, or strigose with 1-1.5 mm hairs, hairs usually evenly distributed, weakly keeled distally, keels scabrous, at least distally, midvein usually more prominent and longer than the lateral veins, margins not hyaline or hyaline near the apices, apices obliquely truncate or obtuse to acute, sometimes mucronate;
lower glumes 4.5-7.5 mm long, 1.5-2.5 mm wide, 5-6-veined;
upper glumes 5.5-8.5 mm long, 2-3 mm wide, 5-7-veined;
lemmas 7.5-10 mm, glabrous or with 1-1.5 mm hairs, hairs usually evenly distributed, sometimes only on the outer portion of the lemmas, apices occasionally awned, awns to 5 mm;
paleas 7-9.5 mm, keels usually scabrous for 1/2 their length;
anthers 5-7 mm.
= 69, 70.
= 42, 43.
Thinopyrum ponticum
Thinopyrum intermedium
Thinopyrum ponticum is native to southern Europe and western Asia. In its native range, it grows in dry and/or saline soils. In the Flora region, T. ponticum is planted along roadsides for soil stabilization, and is spreading naturally in cooler areas because of its tolerance of the saline conditions caused by salting roads in winter. It is sometimes treated as a subspecies of T. elongatum (Host) D.R. Dewey, a diploid species that grows in maritime regions of western Europe.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Thinopyrum intermedium is native to Europe and western Asia. It is widely established in western North America, having been introduced for erosion control, revegetation, forage, and hay. It also occurs in scattered locations further east. One of its advantages for erosion control and revegetation is that it establishes rapidly in many different habitats. In its native range, it grows in dry areas with sandy or stony soils. In Europe, it forms sterile hybrids with Elymus repens; no such hybrids are known from North America.
Several subspecies have been recognized within Thinopyrum intermedium, usually based on differences in the vestiture of the glumes and lemmas, the presence or absence of lemma awns, and the color of the plants. Assadi (1994) commented that there was little correlation between the different character states. He grew seeds from several wild plants and, even when most of the offspring resembled the parent plant, there was often segregation of some variants. Crossing experiments showed that hybrids between the morphological variants were fertile, and usually had regular meiosis. He noted, however, that the plants with glabrous spikelets tended to grow in mesophytic habitats, those with hairy glumes and lemmas on dry slopes, and those with ciliate glumes and lemmas at the edges of fields and in wet places. This difference in habitat preference was reiterated by Ogle (2001). Because of this ecological distinction, they are formally recognized here as subspecies. Plants with hairs only near the lemma margins are included under T. intemedium subsp. intermedium. They may be derived from crosses between the hairy and glabrous plants, a possibility that has not been experimentally evaluated. There seems to be little correlation between spikelet vestiture and that of the leaves and stems.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Lemmas and glumes glabrous | subsp. intermedium |
1. Lemmas with hairs, sometimes only on the margins, hairs 1-1.5 mm long; glumes usually hairy throughout, sometimes glabrous but scabrous over the veins | subsp. barbulatum |
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
IL Wildflowers, 
KS Wildflowers, 
MO Plants, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
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- 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
