| Hilaria mutica | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Clade: | Commelinids |
| Order: | Poales |
| Family: | Poaceae |
| Subfamily: | Chloridoideae |
| Genus: | Hilaria |
| Species: | H. mutica |
| Binomial name | |
| Hilaria mutica | |
| Synonyms | |
Pleuraphis muticaBuckley | |
Hilaria mutica,synonymPleuraphis mutica,[2] is a species ofgrass known by thecommon nametobosa, ortobosa grass. It is native to NorthernMexico, and theSouthwestern United States, in Arizona,New Mexico, Oklahoma, and Texas.[3]
Hilaria mutica is perennial grass that isrhizomatous and formssod. It usually grows 30 to 60 cm (0.98 to 1.97 ft) tall, sometimes reaching up to 90 cm (3.0 ft). The stems have decumbent bases and erect tops.
Most of the stiff, hairless leaves are basal. They are up to 15 cm (5.9 in) long. The bases of the stems come from a thick, woody rootstock and a system of roots that penetrates up to 1.8 m (5.9 ft) deep in the soil.
Theinflorescence is a few centimeters long and is white,straw, or purplish. Spikelets are borne in clusters of three. The plant reproduces mainly by spreading by its rhizome, and does not often form viable seeds.[3] The plant is susceptible toergot.[4]
Hilaria mutica is one of the most common species on the semidesertgrasslands in the region. It is aclimax species on frequently flooded lowlands. It also occurs on upland territory. Habitat types that feature the grass includepinyon-juniper woodland and mesquite, creosote, and grassyshrubsteppe. It does best on land that is flooded for a few days and then dries up. It also grows on drier soils, and it is somewhatdrought-tolerant.
It grows onclay withhoney mesquite and other species such asburrograss (Scleropogon brevifolius),alkali sacaton (Sporobolus airoides) andsacaton (S. wrightii) and otherdropseed grasses (Sporobolus spp.),grama grasses (Bouteloua spp.),muhly grasses (Muhlenbergia spp.), andtarbush (Flourensia cernua).
Tobosa is an importantforage for cattle and horses in the American Southwest. It is productive and palatable until it becomes rough at maturity. It is especially valuable during drought when it persists after other grasses die. It can be cut intohay when still green. InTexas, it yields 1000 pounds per acre, and this can be increased with careful and deliberate management. In areas with adequate precipitation, burning is used to remove litter, which then stimulates the stems to produce more green matter.
The grass can causeergot poisoning if eaten when infested with the fungus.[3]
