few-flowered panicgrass (Scribner's panicgrass)
Dichanthelium oligosanthes
(Schult.) Gould

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Widely distributed in Iowa, few-flowered panicgrass is the most common species of rosette grass (Dichanthelium) on prairies and in the Loess bluffs. It is usually found in open prairies, meadows, and disturbed ground, but it can occasionally be found in open woodlands, particularly in dry or sandy soils. It typically grows between bunches of taller grasses where there is little vegetation. This species is widespread in the eastern two-thirds of the United States but is also found in the Pacific Northwest, where it extends northward along the coast of British Columbia. Like other species of Dichanthelium, few-flowered 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.

Few-flowered panicgrass is a large-leaved, tufted perennial with a characteristic orange- or purple-colored spot usually visible on one side of the base of the spikelet. The foliage leaves tend to be smooth and hairless on the upper surface although they are often hairy on the lower surface. The leaf sheaths may be smooth or hairy, with the longer hairs having warty bases. The spikelets may lack hairs but often are sparsely short-hairy. Leiberg’s panicgrass (Dichanthelium leibergii) is similar in some ways, but it lacks the spot at the base of the spikelet and it has longer hairs on the spikelets and the leaf blades hairy on both surfaces. Plants of few-flowered panicgrass with only the upper 2-3 internodes elongated in fall or early spring are easily mistaken for Wilcox’s panicgrass (Dichanthelium wilcoxianum), but the latter species also lacks the spot at the base of the spikelet and has leaves only 3-5 mm wide.

Two subspecies are recognized within few-flowered panicgrass and both are known from Iowa: subsp. oligosanthes (usually called few-flowered panicgrass as for the species) and subsp. scribnerianum (usually called Scribner’s panicgrass). Scribner’s panicgrass tends to have slightly smaller but relatively wider spikelets that are smooth to short-hairy and the plants have wider, flat leaf blades. The spot at the base of the spikelet is also more prominent than in few-flowered panicgrass. Schribner’s panicgrass is the more common and widespread subspecies in Iowa, occurring throughout the range of this species in the state. Few-flowered panicgrass tends to have slightly larger but relatively narrower spikelets that are usually short-hairy and the plants have narrower, often slightly rolled leaf blades. It also usually has a mixture of longer, warty-based hairs and shorter fuzzy hairs on the leaf sheaths, whereas Scribner’s panicgrass has only the longer warty-based hairs when hairs are present. Few-flowered panicgrass is found most commonly in northwestern and southeastern Iowa. The two subspecies do intergrade and can be difficult to tell apart. Scribner’s panicgrass is nutritious to livestock and can be grazed in fall, winter and spring, but does not furnish large amounts of forage.

Etymology: Dichanthelium from the Greek di = twice and anth = flowering, referring to the occurrence of two distinct flowering periods; oligosanthes from the Greek oligos = few and anthes = flowering, referring to the characteristic flowering heads of this species; scribnerianum is named for Frank L. Scribner (1851-1938), grass specialist in the U.S. Department of Agriculture.


Plants perennial, tufted. Culms 10-60 cm, bent below, stiffly erect above; nodes smooth to sparsely hairy; internodes often purplish, shiny, smooth or sparsely hairy, sometimes the hairs long. Fall phase initially with the branches ascending to erect from the middle nodes, the plants often becoming somewhat bushy in appearance later in the season. Basal rosettes more or less conspicuous. Leaves along the culms with sheaths shorter than the internodes, smooth to long-hairy, the longer hairs with warty bases, the margins long-hairy at the base, the hairs with warty bases; ligules a fringe of hairs 1-3 mm long; blades 4-10.5 cm long, 3-11 mm wide, flat or partially inrolled, usually glabrous or sparsely hairy on the lower surface, the bases rounded to squared off. Primary flowering heads terminal, 4-8 cm long, 1.5-6 cm wide, more or less pyramid-shaped. Spikelets 2.9-3.9 mm long, 1.5-2.1 mm wide, ellipsoid to broadly obovoid-ellipsoid, smooth to sparsely short-hairy; lower glumes 1-1.8 mm, acute; upper glumes and lower lemmas subequal, upper glumes strongly veined, usually with an orange to purplish spot at the base. Chromosome number 2n = 18.


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