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GRASSES
OF THE COLUMBIA BASIN OF BRITISH COLUMBIA
Four species of the distinctive Oatgrass occur in the Columbia Basin region. Generally these tufted perennials grow to <80 cm tall. Oatgrasses have narrow, flat to inrolled leaves, no auricles and a fringe of hairs where the ligule should be. The spikelet separates Danthonia from most other genera. As with many other members of the Oat tribe to which Danthonia belongs, the prominent rounded to keeled glumes are mostly longer than the flowers (except in Danthonia californica). The flattened, bent (not in immature specimens) and sometimes twisted awn is a dead give away. The awn arises in a depression between two long teeth from the back near the tip of the lemma. Spikelets break apart above the glumes. Important features to note when trying to identify the species are whether the sheaths are hairy or not, whether the flowerhead is open or spikelike and whether the back of the lemma is hairy or not.
Leaves and Stem: Leaves occur at the base and along the stem. Sheaths are hairy and open. Flat to inrolled leaf blades are 1.5-3 mm wide. The ligule is <1 mm longe and consists mostly of hairs. Auricles are absent. Flowerhead and flowers: The sparse flowerhead has two to five spikelets, one each at the ends of the branches, which are as long or longer than the spikelets. The glumes are 14-18 mm long, nearly equal and extend into an awnlike point. Except for the long, bent awn, the first flowers are enclosed in the glumes. However the remaining four to seven flowers usually stick out beyond the tips of the glumes. Lemmas are largely without hairs except at the base and margins. Similar Species: California Oatgrass resembles Timber Oatgrass (Danthonia intermedia), but California Oatgrass has spreading branches adn hairy leaf sheaths, whereas Timber Oatgrass has erect branches and smooth leaf sheaths. The few-flowered stalk arising from a tuft of narrow leaves, and the flattened, twisted awns from between two teeth at the tip of the lemma are diagnostic characters for the Danthonia genus.
Leaves and Stem: The leaf blades are 2-4 mm wide, flat to inrolled, erect to curved and grow mostly at the base where old leaves persist. The leaf blades are especially hairy where they meet the stem. Sheaths are smooth to sparsely hairy and open. The ligules are hardly present, being made of short hairs. Auricles are absent. Flowerhead and Flowers: The flowerhead is narrow, 3-6 cm long and often appears to have the spikelets arranged to one side. Each side branch has one (occasionally two) spikelet with few flowers. The glumes are 13-17 mm long, about equal and enclose most of the several flowers. Lemmas are hairy at the base and along margins. A 10-mm-long, generally bent and twisted, awn emerges from between two teeth at the tip of the lemma. Similar Species: Timber Oatgrass is similar to California Oatgrass. See the Similar Species description for California Oatgrass (Danthonia californica). Futher differences between the two species are: the glumes of Timber Oatgrass are longer than all its flowers, and the flowers are rarely visible, whereas in California Oatgrass the upper flowers on the axis extend slightly beyond the glumes.
Leaves and Stem: The leaves mostly form a dense mass at the base, though some are scattered along the stem. Old basal leaves are curved to strongly curled. The leaf blades are 0.5-2.0 mm wide and inrolled. Sheaths are open and smooth to slightly hairy with especially long hairs at the throat and in the collar. The ligule of hairs is scarcely 0.5 mm high, and there are no auricles. Flowerhead and Flowers: The narrow, spiky flowerhead is only 2-5 cm long and secund. The very-short branches have one or two spikelets. The slender glumes are about equal in length and both are longer than the flowers (excluding the awn). The lemmas are 4-5 mm long, sparsely hairy on the back and bear two long, prominent teeth at the tip. An 8-9-mm-long flattened awn arises between the teeth. The awn is often twisted, bent and sticks out of the spikelet. Similar Species: Poverty Oatgrass differs from other Oatgrass species because it has a lemma that is <6 mm long, and hairy on the back and margins -- not just hairy on the margins. Sometimes the lemmas may be 7 mm long, but their backs are at least sparsely hairy.
Leaves and Stem: The leaves form a tufted mass at the base and are scattered along the stem. Basal leaves are straight to curved. Leaf blades are 1.0-4.0 mm wide and flat to inrolled. Sheaths are open and usually obviously hairy with especially long hairs at the throat and on the collar. The long, white hairs stick out at right angles to the sheath. The ligule of hairs is scarcely 0.5-1 mm high and there are no auricles. Flowerhead and Flowers: The small, spiky flowerhead usually consists of a single spikelet (rarely more) and is about 1-3 cm long. The first glume is slightly shorter than the second and both are taller than the flowers (excluding the awn). The lemmas are 9-12 mm long and smooth on the back with hairs along the margin and perhaps at the base. They bear two prominent teeth at the tip. A flattened awn arises between the teeth. The awn is often twisted, bent and sticks out of the spikelet. Similar Species: One-spike Oatgrass differs from other Oatgrass species because it usually has a single spikelet in a spikelike flowerhead. Compared to Poverty Oatgrass, it has much longer lemmas (9-12 mm vs <6 mm) that are smooth, not hairy, on the back.
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