Excerpts from Jim Conrad's
from the the September 30, 2012 Newsletter issued from the valley of the Dry Frio River in northern Uvalde County, southwestern Texas, on the southern border of the Edwards Plateau, USA
In a variety of habitats, but especially on limestone outcrops along the little Dry Frio River behind the cabin, there's a certain knee-high clumpgrass fruiting in a very conspicuous and unusual manner nowadays. You can see a clump with the Dry Frio's shallow waters in the background above.
The "slender pagoda" effect, with the clusters of spikelets hanging downward -- "pendent," as botanists say -- is a fine field mark. And this is a grass worth knowing since it's one of the main native short-grass prairie species throughout the Americas, from Canada to Argentina. It's so important for grazing cattle that it's the State Grass of Texas. Usually called Sideoats Grama, it's BOUTELOUA CURTIPENDULA.
In Texas Senate Concurrent Resolution #31, among several "whereases" explaining why Sideoats Grama should be the state grass, there's the following:
"WHEREAS, Although there are many desirable forage species native to the State, one variety, sideoats grama, occurs on a greater diversity of soils than possibly any other grass; on rangelands of West Texas it is the backbone of the ranching industry; and
WHEREAS, Sideoats grama produces a high quality, nutritious forage which is relished by all classes of livestock and wildlife; it is one of the State's most attractive grasses as well, with its brilliant orange anthers and the purple inflorescence it produces upon maturity; each spike turns to one side of the seed stalk at maturity, giving the grass its name of sideoats; and
WHEREAS, This grass is also favored because it is not only winter hardy but is highly drought resistant due to the fact that it is a long-lived perennial grass with rhizomes; in some years the grass produces two seed crops, and growth begins early in the spring and continues until early fall; and... "
You can read Resolution #31 in its entirety at http://www.netstate.com/states/symb/grasses/tx_sideoats_grama.htm.
If you're familiar with grass-flower structure you'll recognize that Sideoats Grama's flowering and fruiting heads are a bit unusual. You can see some up close below:
You can review glass-flower anatomy on our grass page at http://www.backyardnature.net/fl_grass.htm.
The tricky thing with Sideoats Grama flowers is that each compact, pendent item in the picture is not a spikelet but rather a cluster of spikelets. In grass-talk, a spikelet is a unit holding one or more florets (flowers). For most grasses such clusters are spikelets, but Sideoats Grama crams one to eight spikelets into a cluster, and then each spikelet contains one or two florets. Also, in most grasses once the achene-type fruits are ready to fall, either a floret falls from its spikelet, or a spikelet falls from the stem, but with Sideoats Grama the whole group of spikelets falls as a unit.
So, this is one of the most important flowering native plants in the Americas, yet few people have heard of it. It occurs throughout the US and much of Canada, though in Kentucky and Mississippi I saw it only rarely, normally in especially dry natural areas. Really, Sideoats Grama prefers drier habitats than normally found there.