Buchloe dactyloides (Buffalo Grass)
|Also known as:|
|Habitat:||sun; dry; prairies, plains, rock outcrops|
|Fruiting season:||July - September|
|Plant height:||1 to 8 inches|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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Separate staminate (male) and pistillate (female) flowers usually on different plants (dioecious). Staminate flowers are the showier of the two, with a raceme-like cluster of 1 to 3 branches at the top of the stem, each branch ¼ to ½ inch long and short-stalked, the terminal branch erect to spreading, the lateral branches ascending to spreading. A branch has 6 to 12 spikelets (flower clusters), arranged on one side of the rachis (stalk), tightly packed in 2 rows. Spikelets are light green, 4 to 5.5 mm long, each with 2 florets.
At the base of a staminate spikelet is a pair of bracts (glumes) that are whitish to light green, narrowly egg-shaped with 1 to 3 green veins, minutely hairy along the keel, the lower glume smaller than the upper. Surrounding a floret is pair of bracts (lemma and palea), the lemma longer than the glumes and 3-veined. Florets have large, bright red-orange stamens.
Pistillate spikes are less conspicuous, mostly hidden by the leaves. A pair of spikes is tightly clustered at the tip of the stem and subtended by a broad, scale-like, awn-tipped bract. Each spike has 3 to 5 spikelets, each spikelet with a single floret. The lower glume is obscure or absent, the upper is light green, 3 to 4 mm long with 3 or 4 narrow, darker green, finger-like lobes more or less as long as the glume body. The lemma is 2.5 to 3.5 mm long, 3-lobed like the glume, and is slightly longer than the palea. The lemma and palea are mostly hidden by the glume. Florets have purple, feathery styles.
Leaves and stems:
Leaves are basal and alternate, ¾ to 5 inches long, 1 to 2.5 mm wide, flat, variously covered in long, white, spreading hairs, more densely on the lower plant and more sparsely to nearly hairless above. Sheaths are similarly hairy on the lower stem and mostly hairless above, and may have a denser band of hairs around the base of the blade. The ligule (membrane where the leaf joins the sheath) is a fringe of white hairs up to .5 mm long. Nodes are smooth.
Stems are mostly erect, unbranched or branched from the base, hairless, forming loose to dense clumps, and usually forming mats from horizontal stems (stolons), with vegetative shoots emerging at regular intervals.
Pistillate spikelets mature to creamy white to light brown, the glume and lemma forming a hardened shell. The entire spike drops off at maturity. The grains (seeds) are oblong-elliptic and brown, 2 to 2.5 mm long. Staminate spikelets dry light brown and drop off individually, leaving the glumes behind.
Buffalo Grass is one of the few dioecious grasses, though occasionally a plant will have both male and female flowers. A common grass of the Great Plains, its natural habitat in Minnesota is limited to a few rock outcrops in our southwest counties, but it is widely available as an alternative to turf grass so has been planted in many other areas around the state. According to the DNR, it was listed as a state Special Concern species in 1984 due to its limited natural habitat, which is at risk from bedrock mining and from over-grazing, where livestock damage the thin soils around the outcrops. It is not likely to be confused with any other grass. The female plants are quite inconspicuous, the stem only 1 to a few inches tall and usually obscured by the leaves. Males are easier to spot and may reach 8 inches tall, though 4 or 5 inches is common, even less in areas that are subject to mowing.
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- Buffalo Grass plant
- Buffalo Grass in a rock outcrop
- planted Buffalo Grass mixed with turf grass
- plant with 3 male spikes
Photos by K. Chayka taken at plantings in Hennepin and Ramsey counties. Photos courtesy Peter M. Dziuk taken at Blue Mounds State Park, Rock County, and in Hennepin and Ramsey counties.
Have you seen this plant in Minnesota, or have any other comments about it?