| Blue grama | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Clade: | Commelinids |
| Order: | Poales |
| Family: | Poaceae |
| Subfamily: | Chloridoideae |
| Genus: | Bouteloua |
| Species: | B. gracilis |
| Binomial name | |
| Bouteloua gracilis | |
Bouteloua gracilis, theblue grama, is a long-lived, warm-season (C4)perennialgrass, native toNorth America.[2][4][5]
It is most commonly found fromAlberta, Canada, east toManitoba and south across theRocky Mountains,Great Plains, and U.S.Midwest states, onto the northernMexican Plateau inMexico.
Blue grama accounts for most of the netprimary productivity in theshortgrass prairie of the central and southernGreat Plains. It is a green or greyish, low-growing, drought-tolerant grass with limited maintenance.[6]
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Blue grama has green to greyish leaves less than 3 mm (0.1 in) wide and 1 to 10 in (25 to 250 mm) long. The overall height of the plant is 6 to 12 in (15 to 30 cm) at maturity.[7]
The flowering stems (culms) are 7 to 18 in (18 to 46 cm) long. At the top are one to four, usually two,[8] comb-likespikes, which extend out at a sharp angle from the flowering stem.[7] Each spike has 20 to 90spikelets.[7] Each spikelet is 5 to 6 mm (0.20 to 0.24 in) long, and has one fertilefloret and one or two reduced sterile ones.[9] Below the florets are two glumes, one 1.5 to 3 mm (0.06 to 0.12 in) long and the other 3.5 to 6 mm (0.14 to 0.24 in) long.[9] The fertile floret has alemma (bract) 5 to 5.5 mm (0.20 to 0.22 in) long, with three shortawns (bristles) at the tip, and the sterile floret has a lemma about 2 mm (0.08 in) long with three awns about 5 mm (0.2 in) long.[8][10] If pollinated, the fertile floret produces an oblong-elliptic brown seed 2.5 to 3 mm (0.10 to 0.12 in) long.[11] When the seed is mature, the whole spikelet detaches, but the two glumes remain.
Theroots generally grow 12 to 18 in (30 to 46 cm) outwards, and 3 to 6.5 ft (0.9 to 2.0 m) deep.[7]
Blue grama is readily established fromseed, but depends more onvegetative reproduction viatillers. Seed production is slow, and depends on soil moisture and temperature. Seedsdispersed bywind only reach a few meters (6 ft); further distances are reached with insects, birds, andmammals as dispersal agents.Seedling establishment, survival, and growth are greatest when isolated from neighboring adult plants, which effectively exploit water in the seedling's root zone. Successful establishment requires a modest amount of soil moisture during the extension and development ofadventitious roots.[7]
Established plants aregrazing-, cold-, anddrought-tolerant, though prolonged drought leads to a reduction in root number and extent. They employ an opportunistic water-use strategy, rapidly using water when available, and becomingdormant during less-favorable conditions. In terms ofsuccessional status, blue grama is a lateseral toclimax species. Recovery followingdisturbance is slow and depends on the type and extent of the disturbance.[7]
Blue grama has the widest distribution of all grama grasses. It will grow on most soil types, and readily adapts to local conditions. It can be found as far north asAlberta, and as far south as Mexico. It is present in most of the Midwestern United States, extending east to Missouri and Texas, and as far west as Southern California. It has beenintroduced to some eastern states, as well as South America.[12]
Blue grama is valued asforage, and is the most valuable grama. It is an ideal range grass in the southwest. It will survive heavy grazing and extreme drought, and is quite palatable to livestock.[12] Grazing of blue grama rangelands might also prevent invasion of undesirableweedy plants.[13]
Blue grama is grown by thehorticulture industry, and used inperennial gardens, naturalistic andnative plantlandscaping,habitatrestoration projects, and residential, civic, and highwayerosion control. Blue grama flowers are also used in dried flower arrangements. Blue grama is thestate grass ofColorado andNew Mexico. It is listed as anendangered species inIllinois.[2]
Blue grama has a largegenome relative to other grama grasses.[14] It can bediploid ortetraploid.[15]
Among theZuni people, the grass bunches are tied together and the severed end is used as a hairbrush, the other as a broom. Bunches are also used to strain goat's milk.[16] TheCostanoan, orOhlone, use(d) the hollow stems as straws.[17] TheNavajo use(d) it as sheep and horse feed.[18]
Blue grama is the dominant species of the USshortgrass steppe ecoregion.[19][20] Populations of blue grama across the great plains are genetically differentiated (even at small spatial scales) and showfunctional trait variance connected to climate.[21][22][15] Blue grama from more arid grasslands are also characterized by greaterphenotypic plasticity.[21]
It is a larval host to theGarita skipperling,green skipper,Pahaska skipper,Rhesus skipper,Simius roadside skipper, and theUncas skipper.[23]
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