Panicum dichotomiflorum Michx.

Map

Inflorescence

image credit: Bonnie_Semmling

Plant

image credit: Quinten_Wiegersma

image credit: Quinten_Wiegersma

Description

Plants annual or short-lived perennials in the Flora region, perennial in the tropics; usually terrestrial, sometimes aquatic but not floating. Culms 5-200 cm tall, 0.4-3 mm thick, decumbent to erect, commonly geniculate to ascending, rooting at the lower nodes when in water, simple to divergently branched from the lower and middle nodes, usually succulent, slightly compressed, glabrous; nodes usually swollen, sometimes constricted on robust plants, glabrous; internodes glabrous, shiny, pale green to purplish. Sheaths compressed, inflated, sparsely pubescent near the base, elsewhere mostly glabrous, sparsely pilose, or hispid, hairs sometimes papillose-based, margins or throat ciliate, with papillose-based hairs; ligules 0.5-2 mm; blades 10-65 cm long, 3-25 mm wide, glabrous or sparsely pilose, often scabrous near the margins, midribs stout, whitish. Panicles 4-40 cm, diffuse, lax, with a few spikelets; branches to 15 cm, alternate or opposite, occasionally verticillate, ascending to spreading, stiff, scabrous; pedicels 1-6 mm, sharply 3-angled, scabrous, expanded to cuplike apices, appressed mostly to the abaxial side of the branches. Spikelets 1.8-3.8 mm long, 0.7-1.2 mm wide, ellipsoid to narrowly ovoid, light green to red-purple, glabrous, acute to acuminate. Lower glumes 0.6-1.2 mm, 1/4 - 1/3 as long as the spikelets, 0-3-veined, obtuse to acute; upper glumes and lower lemmas similar, exceeding the upper florets by 0.3-0.6 mm, 7-9-veined; lower paleas vestigial to almost as long as the lower lemmas; lower florets sterile; upper florets 1.4-2.5 mm long, 0.7-1.1 mm wide, narrowly ellipsoid, smooth, shiny, stramineous to nigrescent, with pale veins. 2n = 36, 54.
(Description source: Barkworth, M.E., Capels, K.M., Long, S. & Piep, M.B. (eds.) 2003. Flora of North America, north of Mexico. Volume 25. Magnoliophyta: Commelinidae (in part): Poaceae, Part 2. Oxford University Press, New York. 783 pp http://floranorthamerica.org/Panicum_dichotomiflorum )

Geniculate or erect annuals 10-120 cm tall, usually glabrous; culms usually branched. Ligule a ciliate membrane, 1-2 mm long; blades 10-50 cm long, 0.3-2 cm wide, flat, glabrous or sparsely pubescent. Panicles 4-50 cm long, terminal and axillary; spikelets 2-3.2 mm long, oblongovoid, acute, glabrous; first glume 0.6-1 mm long, 1/5-1/4 as long as spikelet, obtuse to truncate, 3-nerved, broadly clasping, second glume 7-nerved; first floret sterile or staminate, first lemma 7-nerved, first palea absent or as long as first lemma; second floret 1.7-2.1 mm long, acute, glossy, smooth; anthers 1.2-1.4 mm long. [2n = 36, 54.]
(Description source: O’Connor, P.J. 1990. Poaceae, pp. 1481–1604. In: Wagner W.L., Herbst D.R. & Sohmer S.H. (eds.)., Manual of the flowering plant of Hawaiʻi. Vol. 2. University of Hawaii Press & Bishop Museum Press, Honolulu )