side-oats grama (mesquite grass, gramagrass)
Bouteloua curtipendula (Michx.) Torrey

click thumbnail to see a larger image

planthabithabitliguleinflorescencepanicle branchspikeletillustration

Sideoats grama is one of Iowa’s most beautiful native grasses. The short, densely flowered, comb-like branches of the flowering heads hang to one side of the stem in the manner of a feathered lance, and Kiowa warriors who had killed an enemy with a lance often wore a dried stem as a decoration (Vestal and Schultes, 1939). This species flowers from late June to October in Iowa, and when the flowers are ripe for pollination, the bright orange-red anthers dangle from the spikelets, providing a startling contrast to the green foliage. When seeds are ripe in the fall, the individual branches fall off and are dispersed.

Sideoats grama was one of the dominant grasses of the prairie that covered most of pre-settlement Iowa, especially in the drier areas. It is still fairly common throughout most of Iowa. The native range of sideoats grama extends from southern Canada through Mexico and Central America into Western South America, where it usually grows in loamy, well-drained, prairie soils. It is frequently planted as an ornamental or as part of native lawn mixtures. This species is also highly palatable to all classes of livestock and provides good forage for many wild animals as well.

Etymology: The generic name Bouteloua is given in honor of the Spanish botanists Claudio (1774-1842) and Esteban (1776-1813) Boutelou y Soldevilla. Grasses of this genus are often referred to as grama grasses, from Latin gramen = grass. The specific epithet curtipendula comes from the Latin curtus = short and pendulous = hanging down, referring to the appearance of the panicle branches.

 

Plants perennial, rhizomatous. Culms 10-100 cm, solid, usually erect, but sometimes leaning, solitary or arising in small groups. Leaves with sheaths mostly glabrous, sometimes long hairy near the summit; ligules 0.3-0.5 mm long, membranous, ciliate; blades 18-30 cm long, 1.4-6.5 mm wide; flat at maturity, folded when dry, usually smooth on the lower surface and scabrous on the upper, often thinly to densely long hairy, the hairs along the margin near the ligule blister-based. Flowering heads elongate, 13-40 cm long, with 10-45 drooping branches. Branches 0.8-1.3 cm long, with 3-9 crowded spikelets per branch, axes extending 3-5 mm beyond the bases of the terminal spikelets; disarticulation at the bases of the branches. Spikelets 7-9.5 mm long with 1 perfect and 1-2 sterile, rudimentary florets; glumes unequal, glabrous or scabrous, lower glumes 2.5-6 mm long, one half or more as long as the upper glumes; upper glumes 5.5-8 mm long; fertile lemmas 3-6.5 mm long, 3-lobed, 3-veined, veins usually extending as short mucros to 1 mm; anthers usually orange to reddish, sometimes yellow or purple; rudimentary florets 0.4-3.5 mm long, sterile, variable, usually a glabrous lemma with 3 unequally developed awns, central awns 1.5-7 mm. Chromosome number 2n = (20) 40, 41-103.

 

home - common name index - scientific name index - database - picture key - weedy grasses - ornamental grasses - Ada Hayden Herbarium - ISU