Leiberg's panicgrass
Dichanthelium leibergii (Vasey) Freckmann

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planthabitligulespikeletillustration

Leiberg’s panicgrass is common to frequent on dry upland prairies and sandy woodlands in northwest Iowa, becoming less frequent to the east and south.  In the United States, this species is found in the Upper Midwest and into the Northeast along the Great Lakes, and it also extends into southern Canada.  Like other species of Dichanthelium, Leiberg’s panicgrass is characterized by two distinct blooming periods.  The conspicuous primary flowering heads are terminal to the culms and are produced from late May into early July.  Secondary flowering heads are produced from the leaf axils from late June into September. The primary flowering heads usually have a lower seed set than the secondary ones, which have flowers that remain closed and are self-pollinated. 

Among the rosette grasses (Dichanthelium spp.), Leiberg’s panicgrass is recognized by having leaf blades that are hairy on both surfaces and relatively large spikelets, which measure from 3.3 to 4 mm in length.  The long, warty-based hairs on the spikelets are also distinctive, as is the usual presence of warty-based hairs on the leaf sheaths.  This species does not become very bushy as it does not produce many lateral branches later in the season.  Leiberg’s panicgrass is most similar to the few-flowered panicgrass (Dichanthelium oligosanthes), but the latter species has a more or less prominent orange- to purple-colored dot at the base of the spikelet on one side and at least the upper surface of the leaves is usually hairless and smooth.  When hairs are present on the spikelets of few-flowered panicgrass, they are sparser and shorter than in Leiberg’s panicgrass.

Etymology: Dichanthelium from the Greek di = twice and anth = flowering, referring to the occurrence of two distinct flowering periods; the epithet leibergii honors John Bernhard Leiberg (1853-1913), who first recognized this species.

 

Plants perennial, tufted, arising from short, knotty rhizomes no more than 2 mm thick. Culms (10-) 20-75 cm tall, erect to bent below; nodes with sparse spreading long hairs; internodes mostly elongated, smooth to short-hairy. Fall phase with only a few more or less erect branches from the lower and middle nodes, therefore not becoming bushy-branched. Basal rosettes conspicuous. Leaves along the culms with sheaths shorter than the internodes, with ascending, warty-based hairs; ligules 0.3-0.5 mm long or sometimes nearly lacking; blades 5-13.5 cm long, 6-13 mm wide, sparsely to densely covered with warty-based hairs on both surfaces, the bases squared off to rounded, the margins bearing long, warty-based hairs. Primary flowering heads terminal, eventually held above the foliage, 4.5-8.5 cm long, 2-4 cm wide, more or less pyramid-shaped.  Spikelets 3.3-3.8 (-4) mm long, ellipsoid-obovoid, the tips rounded, long-hairy, the hairs with warty bases; lower glumes often relatively long, 2-2.7 mm, triangular; upper glume and lower lemma about equal. Chromosome number 2n = 18.

 

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