Panicum amarum

Elliott
Common names: Bitter beachgrass
Treatment appears in FNA Volume 25. Treatment on page 472.

Plants perennial; rhizomatous, rhizomes stout, glabrous and glaucous throughout. Culms 20-250 cm tall, 3-10 mm thick, erect or decumbent, simple or branched from the lower nodes; nodes glabrous; internodes glabrous, glaucous. Sheaths 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. Panicles 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. Spikelets 4-7.7 mm long, 1.5-2 mm wide, narrowly ovoid, glabrous, acuminate; lower florets staminate. Glumes 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. 2n = 36, 54.

Distribution

Conn., N.J., N.Y., Del., Fla., La., Md., Miss., N.C., Tex., Va., W.Va., Ala., N.Mex., Pa., R.I., Ga., Mass., S.C.

Discussion

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.

Selected References

None.

Key

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 Panicum amarum 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 Panicum amarum subsp. amarum

No values specified."decumbent" is not a number."-11-veined" is not declared as a valid unit of measurement for this property.

... more about "Panicum amarum"
puberulent +
scabridulous +
acute +, obtuse +, rounded +  and attenuate +
anatomy +  and kranz +
Robert W. Freckmann +  and Michel G. Lelong +
Elliott +
1 (?) +  and 3 (?) +
keeled +  and rounded +
divergent +  and parallel +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
membranous +
disarticulating +  and pseudopetiolate +
non-radiate +  and radiate +
7 cm70 mm <br />0.07 m <br /> (50 cm500 mm <br />0.5 m <br />) +
pubescent +  and glabrous +
filiform +  and ovate flat +
spikelike +
0 cm0 mm <br />0 m <br /> (1 cm10 mm <br />0.01 m <br />) +
not developed +
terete +  and compressed +
thick-walled +
sometimes longer +
Bitter beachgrass +
small green +
branched +  and simple +
20 cm200 mm <br />0.2 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +
decumbent +  and erect +
20 cm200 mm <br />0.2 m <br /> (300 cm3,000 mm <br />3 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (1 cm10 mm <br />0.01 m <br />) +
Conn. +, N.J. +, N.Y. +, Del. +, Fla. +, La. +, Md. +, Miss. +, N.C. +, Tex. +, Va. +, W.Va. +, Ala. +, N.Mex. +, Pa. +, R.I. +, Ga. +, Mass. +  and S.C. +
capillary +
germination +
pistillate +  and staminate +
sometimes longer +
compressed +  and terete +
shorter or longer +
subtending +
pubescent +  and glabrous +
tuberculate +
unequal +
membranous +
well-developed +
uncinate +
Oval (?) +  and Round (?) +
bracteate +  and ebracteate +
hollow +  and solid +
glaucous +  and glabrous +
scale-like +
coriaceous +
0.1 cm1 mm <br />0.001 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
membranous +
inconspicuous +
1/2 +  and 4/5 +
acuminate +, truncate +  and acute +
0.28 cm2.8 mm <br />0.0028 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
oblong-hastate +
0.3 cm3 mm <br />0.003 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
complex +  and simple +
concealed +  and prominent +
2 +  and 1 +
10cm +  and 80cm +
subterranean +
pyramidal +
2 cm20 mm <br />0.02 m <br /> (17 cm170 mm <br />0.17 m <br />) +
simple +  and compound +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
dry +  and fleshy +
opposite +  and whorled +
strongly ascending;appressed +
glaucous +  and glabrous +
shorter or longer +
not keeled +
in triplets +  and paired +
0.4 cm4 mm <br />0.004 m <br /> (0.77 cm7.7 mm <br />0.0077 m <br />) +
1 +  and 60 +
unisexual +  and bisexual +
acuminate +  and ovoid +
0.1 cm1 mm <br />0.001 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
1.5mm +  and 2mm +
1 +  and 3 +
compound +  and simple +
fused +  and free +
2 +  and 3 +
dome--shaped +  and triangular +
Gramineae +
Panicum amarum +
Panicum sect. Repentia +
species +
membranous +
stipitate +  and sessile +
0.24 cm2.4 mm <br />0.0024 m <br /> (0.39 cm3.9 mm <br />0.0039 m <br />) +
narrowly ovoid +  and oblong +
0.1 cm1 mm <br />0.001 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
0.39 cm3.9 mm <br />0.0039 m <br /> (0.76 cm7.6 mm <br />0.0076 m <br />) +
pubescent +  and glabrous +
rugose +  and verrucose +
chartaceous-indurate +  and rigid +
aquatic +  and terrestrial +
dioecious +, monoecious +  and synoecious +