Dichanthelium polyanthes (Schult.) Mohlenbr. (redirected from: Panicum firmandum)
Family: Poaceae
[Dichanthelium sphaerocarpon var. isophyllum (Scribn.) Gould & C.A. Clark,  more...]
Dichanthelium polyanthes image

Plants cespitose, with few culms per tuft. Basal rosettes well-differentiated; blades 3-8 cm long, often to 2 cm wide, ovate-lanceolate. Culms 30-95 cm, nearly erect, fairly stout; nodes glabrous or puberulent; internodes usually glabrous; fall phase with few, long-ascending branches, sparingly rebranched, branches arising mostly near the base of the culms. Cauline leaves 4-7; sheaths shorter than the internodes, mostly glabrous, margins ciliate; ligules vestigial; blades 10-25 cm long, 14-25 mm wide, thick, firm, often light green, veins evident (some more prominent than others), bases cordate, with papillose-based cilia, margins whitish, cartilaginous. Primary panicles 7-20 cm, less than 1/2 as wide as long, exserted. Spikelets 1.3-1.7 mm, broadly ellipsoid-spherical, often purplish at the base, puberulent. Lower glumes 0.4-0.7 mm, acute to obtuse, upper florets 1.1-1.4 mm, broadly ellipsoid, blunt. 2n = 18.

Dichanthelium polyanthes grows in woods, stream banks, and ditches, and is restricted to the eastern United States. It occasionally hybridizes with D. sphaerocarpon.

Perennial herb, tufted 30 cm - 1 m tall

Inflorescence: a terminal, branched arrangement of spikelets (panicle). Primary panicles atop the culms, 7 - 20 cm long, less than half as wide as long, exserted. Secondary panicles (when present) atop the branches.

Fruit: a caryopsis, indehiscent, enclosed within the persistent lemma and palea.

Culm: nearly upright, stout, 30 cm - 1 m long, round in cross-section, hollow. Nodes sometimes minutely hairy. Fall phase sparsely branching, with a few long-ascending branches arising from near the base of the culms.

Spikelets: often purplish basally, 1 - 1.5 mm long, broadly spherical-ellipsoid, minutely hairy.

Basal leaves: in a rosette. Blades 3 - 8 cm long, to 2 cm wide, egg- lance-shaped, distinct from stem blades.

Stem leaves: four to seven, alternate, two-ranked. Sheaths shorter than internodes, fringed with hairs. Ligules rudimentary. Blades firm, thick, whitish along the margins, distinctly longer and narrower than basal leaves, 10 - 25 cm long, 1.5 - 2.5 cm wide, lance-shaped with a heart-shaped base, veined, fringed with bumpy-based hairs basally.

Glumes:: Lower glumes about 0.5 mm long, blunt to pointed at the apex. Upper glumes rounded to pointed at the apex.

Lemmas:: Lower lemmas similar to upper glumes. Upper lemmas longitudinally lined, shiny, with rolled-up margins above.

Paleas:: Lower paleas shorter than lower lemmas, thin. Upper paleas longitudinally lined.

Florets:: Upper florets bisexual, stalkless, 1 - 1.5 mm long, broadly ellipsoid with a blunt apex, plump. Anthers three. Stigmas red.

Similar species: No information at this time.

Flowering: June to October

Habitat and ecology: In the Chicago Region, this species is known only from Berrien County, Michigan. There it was found at a truck-weighing station in moist sand.

Occurence in the Chicago region: native

Etymology: Dichanthelium comes from the Greek words di, meaning twice, and anth, meaning flowering, referring to plants that may have two flowering periods. Polyanthes means many-flowered.

Author: The Morton Arboretum

From Flora of Indiana (1940) by Charles C. Deam

This species is restricted to the southern half of the state and is rather frequent in the counties along the Ohio River. It prefers a slightly acid soil and is found in dry soil associated with black oak, and in moist soil associated with sweet gum. It is also found sparingly in fallow fields.

Culms few in a tuft, stout and erect, 4-10 dm, glabrous; sheaths usually all longer than the internodes, glabrous on the back, ciliate with hairs usually under 1 mm; ligule none; blades cordate and papillose-ciliate at base, the largest 12-20 cm נ15-30 mm, the secondary veins in sets of usually 6-9 between the well differentiated primary veins; flag-lf usually 10-15+ cm; panicle 8-18 cm, seldom over half as wide, with ascending branches; spikelets (excluding the first glume) almost spherical, minutely puberulent, 1.3-1.9 mm; first glume a third to two-fifths as long, broadly rounded; autumnal phase scarcely different, usually producing a few flowering branches from the lower nodes; 2n=18. Dry or damp soil, usually in open woods; N.Y. to Ind., Mo., and Okla., s. to Ga. and Tex. (Dichanthelium p.; Dichanthelium sphaerocarpon var. isophyllum)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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