Panicum hirsutum

Sw.
Common names: Giant witchgrass
Treatment appears in FNA Volume 25.

Plants perennial; forming large clumps from short rhizomes. Culms 100-300 cm tall, 4-10 mm thick, decumbent, semiwoody 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. Sheaths 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. Panicles 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. Spikelets 1.8-2.5 mm long, 0.5-1 mm wide, narrowly ellipsoid, glabrous. Lower 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. 2n = 36.

Discussion

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.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number."thick" is not a number."-11-veined" is not declared as a valid unit of measurement for this property.

... more about "Panicum hirsutum"
puberulent +
acute +, obtuse +, rounded +  and attenuate +
anatomy +  and kranz +
Robert W. Freckmann +  and Michel G. Lelong +
1 (?) +  and 3 (?) +
keeled +  and rounded +
divergent +  and parallel +
intravaginal +, extravaginal +, branching +  and basal +
subcordate +  and cordate +
swelling +
membranous +
disarticulating +  and pseudopetiolate +
non-radiate +  and radiate +
20 cm200 mm <br />0.2 m <br /> (50 cm500 mm <br />0.5 m <br />) +
with involute margins +  and flat +
pubescent +  and glabrous +
filiform +  and ovate flat +
1.5 cm15 mm <br />0.015 m <br /> (4 cm40 mm <br />0.04 m <br />) +
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 +
more densely pubescent +
Giant witchgrass +
small green +
branching +  and simple +
100 cm1,000 mm <br />1 m <br /> (300 cm3,000 mm <br />3 m <br />) +
decumbent +  and erect +
not compressed +
2 cm20 mm <br />0.02 m <br /> (300 cm3,000 mm <br />3 m <br />) +
semiwoody +
0.4 cm4 mm <br />0.004 m <br /> (1 cm10 mm <br />0.01 m <br />) +
capillary +
germination +
pistillate +  and staminate +
sometimes longer +
compressed +  and terete +
shorter or longer +
subtending +
pubescent +  and glabrous +
tuberculate +
unequal +
membranous +
well-developed +
papillose-based +
uncinate +
Oval (?) +  and Round (?) +
bracteate +  and ebracteate +
hollow +  and solid +
with papillose-based hairs +  and glabrous +
coriaceous +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
membranous +
inconspicuous +
acute +  and attenuate +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.14 cm1.4 mm <br />0.0014 m <br />) +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.17 cm1.7 mm <br />0.0017 m <br />) +
hairy +, glabrous +  and ciliate +
complex +  and simple +
concealed +  and prominent +
sericeous +  and pilose +
2 +  and 1 +
25cm +  and 45cm +
subterranean +
pyramidal +
5 cm50 mm <br />0.05 m <br /> (15 cm150 mm <br />0.15 m <br />) +
simple +  and compound +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
dry +  and fleshy +
0 cm0 mm <br />0 m <br /> (15 cm150 mm <br />0.15 m <br />) +
shorter or longer +
irritating +
in triplets +  and paired +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
1 +  and 60 +
unisexual +  and bisexual +
ellipsoid +
0.1 cm1 mm <br />0.001 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
0.5mm +  and 1mm +
1 +  and 3 +
compound +  and simple +
fused +  and free +
2 +  and 3 +
dome--shaped +  and triangular +
Gramineae +
Panicum hirsutum +
Panicum sect. Panicum +
species +
membranous +
stipitate +  and sessile +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.16 cm1.6 mm <br />0.0016 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
pubescent +  and glabrous +
rugose +  and verrucose +
chartaceous-indurate +  and rigid +
aquatic +  and terrestrial +
dioecious +, monoecious +  and synoecious +