Panicum amarum
Panicum bisulcatum
bitter beachgrass, bitter panicgrass, bitter panicum
Japanese panicgrass
20-250 cm tall, 3-10 mm thick, erect or decumbent, simple or branched from the lower nodes;
nodes glabrous;
internodes glabrous, glaucous.
30-150 cm tall, 2-4 mm thick, erect or spreading from a geniculate, non-cormous base, not succulent, glabrous throughout.
shorter or longer than the internodes, not keeled, glabrous;
collars often glaucous and purplish;
ligules 1-5 mm;
blades 7-50 cm long, 2-13 mm wide, erect or ascending, firm, thick, flat basally, more or less involute towards the apices.
shorter or longer than the internodes, rounded, often with minute purple streaks, glabrous, margins shortly ciliate;
ligules to 0.8 mm;
blades 5-28 cm long, 4-14 mm wide, linear, more than 10 times longer than wide, thin, flat, glabrous on both surfaces or sparingly pilose adaxially, bases scabridulous near the margins, prominently veined.
10-80 cm long, 2-17 cm wide, contracted, slightly nodding;
primary branches whorled or opposite, strongly ascending to appressed;
pedicels 0.5-15 mm, appressed to slightly divergent.
12-30 cm long, 9-20 cm wide, usually 1-1.3 times longer than wide, diffuse;
primary branches 8-15 cm, alternate, divergent, slender, scabridulous, much branched, branches confined to the distal 2/3, secondary branches spreading, spikelets confined to the distal 1/2 of the branches;
pedicels 0.5-6 mm.
4-7.7 mm long, 1.5-2 mm wide, narrowly ovoid, glabrous, acuminate;
lower florets staminate.
1.8-2.7 mm long, 0.8-1 mm wide, ellipsoid, dark green, often purple-tinged, usually glabrous, acute to acuminate.
and lower lemmas relatively thick;
lower glumes 2.8-4 mm, 1/2 - 4/5 as long as the spikelets, 3-9-veined, apices of the midveins sometimes scabridulous;
upper glumes and lower lemmas extending 1.5-3 mm beyond the upper florets, apices stiffly gaping;
upper glumes 3.9-7.6 mm, 5-9-veined;
lower lemmas slightly shorter than the upper glumes, 7-9-veined, lower paleas 3-7 mm, oblong-hastate, folded over the anthers;
lower florets staminate;
upper florets 2.4-3.9 mm long, 1-1.8 mm wide, narrowly ovoid to oblong, glabrous, smooth, shiny, lemma margins clasping the paleas only at the base.
glumes 1/3 – 1/2 as long as the spikelets, glabrous, deltoid, acute;
upper glumes and lower lemmas subequal, equaling or exceeding the upper florets, smooth, faintly 5-veined, sparsely pilose with short hairs near the margins and apices, acute;
lower florets sterile;
lower paleas absent or much shorter than the lower lemmas;
upper florets 1.5-1.8 mm, ellipsoid, smooth, lustrous, grayish-brown at maturity, apices sparsely puberulent, obtuse to subacute.
= 36, 54.
= 36.
Panicum amarum
Panicum bisulcatum
Panicum amarum grows in the coastal dunes, wet sandy soils, and the margins of swamps, along the Atlantic Ocean and the Gulf of Mexico from Connecticut to northeastern Mexico. It is also known, as an introduction, from a few inland locations in New Mexico, North Carolina, and West Virginia, as well as in the Bahamas and Cuba.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Panicum bisulcatum is an Asian species that grows in wet, open areas. It has been introduced sporadically, but has rarely become established, on the coastal plain of Georgia and South Carolina. The records from Philadelphia, Pennsylvania are from 1865-1877.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Rhizomes short or ascending; culms often bunched and decumbent, usually more than 120 cm tall; lower glumes with 3-5 less evident veins, the midvein smooth distally; spikelet density high; panicles with 2 or more main branches per node; spikelets 4-5.9 mm long | subsp. amarulum |
1. Rhizomes horizontally elongate; culms mostly solitary, less than 150 cm tall; lower glumes with 7-9 prominent veins, the midvein scabridulous distally; spikelet density moderate; panicles with 1 or 2 main branches per node; spikelets 4.7-7.7 mm long | subsp. amarum |
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