Plants in small or large clumps, with knotty crowns. Basal rosettes
well-differentiated; blades ovate to lanceolate. Culms 20-100
cm, decumbent to erect, sometimes geniculate; nodes usually glabrous,
sometimes sparsely pilose or densely bearded with retrorse hairs; internodes
often purplish or olive green, lowest internodes usually glabrous, varying to
sparsely pubescent; fall phase usually branching freely, especially from
the nodes above the middle, ultimately forming dense, reclining fascicles of
divergent branchlets with numerous reduced, thin, often involute blades, secondary
panicles often reduced, with few spikelets. Cauline leaves 4-7; sheaths
usually shorter than the internodes, usually glabrous, occasionally the lower
sheaths sparsely to densely soft-pubescent, sheaths of the uppermost leaves
sometimes with whitish glandular spots between the prominent veins, margins
of all sheaths glabrous or ciliate; ligules absent or shorter than 1
mm, of hairs; blades 3.5-14 cm long, 5-14 mm wide, usually thin, distant,
spreading to reflexed or (occasionally) ascending, yellow-green to purplish,
usually glabrous on both surfaces or (at least the lower blades) more or less
densely and softly pubescent, bases constricted (in narrow-bladed subspecies)
or narrowly subcordate (in wide-bladed subspecies), margins glabrous or ciliate
basally, glabrous distally, blades of the flag leaves usually spreading. Primary
panicles 3-12 cm, long-exserted, usually with many spikelets; branches
wiry, mostly spreading or ascending, usually glabrous, sometimes scabridulous.
Spikelets 1.5-2.7 mm, usually ellipsoid or obovoid, green or purplish
(at least at the base), glabrous or (less commonly) sparsely pubescent or puberulent,
often prominently veined, obtuse to acute to beaked. Lower glumes usually
less than 1/3 as long as the spikelets, obtuse to acute; upper glumes
usually slightly shorter than or as long as the lower lemmas and upper florets
(occasionally extending beyond the floret); lower florets sterile; upper
florets 1.3-2 mm long, usually less than 1 mm wide, ellipsoid, subacute
to obtuse.
Dichanthelium dichotomum grows in dry, sandy, clayey, or rocky ground,
often in woods, or (more commonly) in moist or wet places, including marshes,
bogs, low woods, swamps, and the moist borders of lakes and ponds. Its range
extends south from the Flora region into the Caribbean. It is a polymorphic
and ubiquitous species, with many of its intergrading subspecies exhibiting
traits of other widespread and variable species such as D.
commutatum, D. laxiflorum,
and D. sphaerocarpon, which
often grow at the same sites.
Perennial herb, tufted 30 cm - 1 m tall Inflorescence: a terminal, branched arrangement of spikelets (panicle). Primary panicles atop the culms, dense, 5 - 12 cm long, long-exserted, wiry-branched. Secondary panicles (when present) atop the branches. Fruit: a caryopsis, indehiscent, enclosed within the persistent lemma and palea. Culm: upright or with knee-like bends, 30 cm - 1 m long, slender, round in cross-section, hollow. Nodes bearded with hairs pointing down. Fall phase sparingly branched, producing reduced leaf blades and secondary panicles. Spikelets: 1.5 - 2 mm long, ellipsoid to reverse egg-shaped, prominently veined. Basal leaves: in a rosette. Blades shortly egg-shaped to lance-shaped, distinct from stem blades. Stem leaves: four to seven, alternate, two-ranked. Sheaths usually shorter than internodes, more or less densely velvety hairy, occasionally white-spotted between veins, fringed with short hairs. Ligules about 0.5 mm long, composed of hairs. Blades thin, spreading to reflexed, distinctly longer and narrower than basal leaves, 5 - 14 cm long, 5 - 14 mm wide, lance-shaped, parallel-veined, more or less densely velvety hairy, fringed with bumpy-based hairs basally. Glumes:: Lower glumes usually less than one-fourth as long as spikelets, blunt to pointed. Upper glumes usually shorter than lower lemmas, 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:: Lower florets sterile. Upper florets bisexual, stalkless, about 1.5 mm long and 0.7 mm wide, ellipsoid with a nearly pointed apex, plump. Anthers three. Stigmas red.
Similar species: No information at this time.
Flowering: May to September
Habitat and ecology: No information at this time.
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. Dichotomum means "forking in pairs." Mattamuskeetense means "of Mattamuskeet Lake" (in North Carolina).
Delicate, slender plants of forests, or more robust, freely branching plants of disturbed habitats, 3-10 dm, the nodes glabrous to densely bearded, the herbage otherwise glabrous or sometimes sparsely hairy; sheaths usually shorter than the internodes; ligule a band of short hairs ca 1 mm or less; blades of main cauline lvs thin, 5-12(-15) cm נ3-10(-13) mm, spreading, the flag-lf nearly or fully as large as the next 2 below; panicles well exsert, open, with ±spreading branches, branchlets, and pedicels, the spikelets never secund; spikelets glabrous or occasionally short-hairy, ellipsoid, 1.5-2.9 mm; first glume a third as long, usually acute; second glume rounded above, shorter than the sterile lemma, both shorter than the fr; autumnal phase much branched above the middle, commonly with fascicles of branchlets, erect or reclining from its own weight, the blades 2-5 cm נ2-5 mm, the panicles much reduced; 2n=18. Woods and open, disturbed habitats; N.B. and s. Can. to Mich., s. to Fla. and Tex. (P. annulum; P. barbulatum; P. clutei; P. lucidum; P. mattamuskeetense; P. microcarpon; P. nitidum; P. roanokense; Dichanthelium d.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.