stiff-leaved panicgrass
Dichanthelium ovale (Elliott) Gould & C. A. Clark

Two subspecies below, click thumbnail to see a larger image

eggleaf rosette grass
Dichanthelium ovale subsp. praecocius (Hitchc. & Chase) Freckmann & Lelong


eggleaf rosette grass
Dichanthelium ovale subsp. pseudopubescens (Nash) Freckmann & Lelong


Stiff-leaved panicgrass is the common hairy rosette- or panicgrass (Dichanthelium) of Iowa prairies. This species is scattered throughout the state, where it occurs in dry upland prairies or sand-plain areas, although it is not documented from a number of eastern and western counties. Stiff-leaved panicgrass is widely distributed in the eastern United States from southernmost Canada to the Gulf Coast. Like other species of Dichanthelium, stiff-leaved panicgrass is characterized by two distinct blooming periods. The conspicuous primary flowering heads are terminal to the culms and are produced in May and June. Secondary flowering heads are produced from the leaf axils from July through 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.

Stiff-leaved panicgrass is recognizable by the extremely long (3-6 mm) and abundant pubescence on the sheaths and leaf blades, sometimes intermixed on the sheaths with fine fuzz, and by its habit of branching at the middle culm nodes very early, soon after flowering on the primary flowering heads.  Late season plants are often very bushy at the top because of the dense bunches of leaves on the secondary branches.  This species is considered to be most similar to hairy panicgrass (Dichanthelium acuminatum), but differs from it in having longer spikelets in addition to the longer hairs on the leaves.

Four subspecies are usually recognized within stiff-leaved panicgrass, but only two are known from Iowa: subsp. praecocius and subsp. pseudopubescens. Subsp. praecocius, or eggleaf rosettegrass) is more widespread in Iowa and is distinguished by having warty-based hairs on the sheaths and internodes with the longer hairs often greater than 4 mm in length. It also has spikelets 1.8-2.1 mm long and leaf blades 2-6 mm wide. The ligule is usually 3-4 mm long. Subsp. pseudopubescens (or white-haired panicgrass) is restricted to sand plain areas in eastern Iowa with one collection from Warren Co. The hairs on its sheaths and internodes lack warty bases and tend to be no more than 3-4 mm long and the longer hairs are often intermixed with fine fuzz on the sheaths. Its spikelets are 2.1-2.9 mm long and leaf blades are a bit wider at 3-8 mm. The ligule is usually less than 2 mm long.

Etymology: Dichanthelium from the Greek di = twice and anth = flowering, referring to the occurrence of two distinct flowering periods; ovale from the Latin ovalis = broadly-elliptic or egg-shaped, referring to the basal rosette leaf shape.


Plants perennial, tufted. Culms 10-45 cm, about 1 mm thick, initially erect, leaning at the base; nodes densely to sparsely hairy; internodes usually long hairy. Fall phase with the branching developing early and forming dense bunches. Basal rosettes conspicuous. Leaves along the culms with sheaths shorter than the internodes, densely or sparsely hairy, the hairs to 4-6 mm long, occasionally with shorter, spreading hairs underneath; ligules 1-4 (-5) mm long; blades 2.5-8.5 cm long, 3-8 mm wide, relatively firm, both surfaces long hairy but sometimes the hairs sparse on the upper surface, the margins often long hairy at the base. Primary flowering heads terminal, 3-6 cm long, 2-5 cm wide, rounded or pyramid-shaped in outline; main axis usually hairy at the base. Spikelets 1.8-2.9 mm long, obovoid or ellipsoid, short hairy; lower glumes about 0.5-1.5 mm long, about 1/3 as long as the spikelet, usually triangular; upper glumes usually slightly shorter than the lower lemmas and upper florets at maturity. Chromosome number 2n = 18.

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