Panicum amarum
Panicum hirsutum
bitter beachgrass, bitter panicgrass, bitter panicum
giant witchgrass, hairy panicgrass
20-250 cm tall, 3-10 mm thick, erect or decumbent, simple or branched from the lower nodes;
nodes glabrous;
internodes glabrous, glaucous.
100-300 cm tall, 4-10 mm thick, decumbent, semi-woody at the base, simple or branching from the middle nodes, prophylls prominent, to 15 cm;
nodes contracted, pilose, sericeous;
internodes glabrous or with papillose-based hairs below the nodes.
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, sparsely hispid, hairs papillose-based, thick, fragile, penetrating and irritating the skin when handled, margins glabrous or ciliate;
collars more densely pubescent than the sheaths, hairs papillose-based;
ligules 1.5-2 mm, with longer hairs immediately behind, growing from the base of the blades;
blades 20-50 cm long, 15-40 mm wide, spreading, flat or with involute margins, bases subcordate to cordate, margins glabrous or sparsely hairy.
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.
terminal, 25-45 cm long, 5-15 cm wide, lax, contracted to diffuse, not breaking at the base and becoming tumbleweeds, all or most secondary branches confined to the distal 1/3;
lower branches whorled;
pedicels 0.5-2 mm, appressed.
4-7.7 mm long, 1.5-2 mm wide, narrowly ovoid, glabrous, acuminate;
lower florets staminate.
1.8-2.5 mm long, 0.5-1 mm wide, narrowly ellipsoid, 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 0.7-1.4 mm, about 1/2 as long as the spikelets, 3-5-veined, acute to attenuate;
upper glumes and lower lemmas subequal, about as long as the spikelets, 7-11-veined;
lower florets sterile;
lower paleas 1.3-1.7 mm;
upper florets 1.2-1.6 mm long, 0.5-0.7 mm wide, glabrous, smooth, shiny, chestnut brown to dark brown.
= 36, 54.
= 36.
Panicum amarum
Panicum hirsutum
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 hirsutum grows along river banks or in ditches, often among shrubs in partial shade. Its range extends from southern Texas through eastern Mexico, Central America, Cuba, and the West Indies to Ecuador, Brazil, and Argentina.
(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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