Panicum amarum
Panicum lacustre
bitter beachgrass, bitter panicgrass, bitter panicum
cypress-swamp panicum, lakeshore panicgrass
20-250 cm tall, 3-10 mm thick, erect or decumbent, simple or branched from the lower nodes;
nodes glabrous;
internodes glabrous, glaucous.
100-150 cm, erect, succulent, with short innovations;
nodes glabrous;
internodes glabrous.
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.
compressed, not keeled, overlapping but narrow, exposing the nodes, bladeless and glabrous or sparsely pilose below the water;
ligules 1-2 mm, membranous, ciliate;
blades 1-30 cm long, 2-4 mm wide, narrow, linear, flat or folded, abaxial surfaces sparsely pubescent, adaxial surfaces sparsely pilose.
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.
10-30 cm, open, with many spikelets;
primary branches fascicled at the base of the panicles, solitary and distant distally;
pedicels 1-4 mm, sharply 3-angled, appressed.
4-7.7 mm long, 1.5-2 mm wide, narrowly ovoid, glabrous, acuminate;
lower florets staminate.
2-2.2 mm, glabrous.
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 truncate to broadly triangular, 1/4 as long as the spikelets, 3-veined;
lower paleas absent;
upper glumes and lower lemmas equal, slightly exceeding the upper florets, 5- or 7-veined, pointed;
lower florets sterile;
upper florets relatively thin, smooth.
= 36, 54.
= unknown.
Panicum amarum
Panicum lacustre
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 lacustre grows in shallow water or wet soil at the edge of cypress ponds in the Everglades of southern Florida. It also grows in Cuba.
(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 |
Go Botany
LA Plants
MD Biodiversity
WildflowerSearch
iNaturalist
USDA Plants Database
