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warty panicgrass

giant witchgrass, hairy panicgrass

Habit Plants annual; weak, ascending or sprawling. Plants perennial; forming large clumps from short rhizomes.
Culms

10-150 cm, slender, wiry, erect at first, ultimately decumbent, sprawling, glabrous, often with purple dots and streaks, branching extensively at the base, rooting at the lower nodes.

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.

Sheaths

often shorter than the internodes, loose, glabrous, margins short-ciliate;

ligules 0.2-0.5 mm, membranous, erose, ciliate;

blades 5-20 cm long, 3-10 mm wide, thin, flat, glabrous on both surfaces, margins scabridulous, apices long-acuminate.

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

5-30 cm, nearly as wide as long;

branches few, capillary, with a few spikelets distally;

pedicels 0.5-10 mm.

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

1.7-2.2 mm long, about 1 mm wide, ellipsoid or obovoid, glabrous, faintly veined, subacute or obtuse at the apices.

1.8-2.5 mm long, 0.5-1 mm wide, narrowly ellipsoid, glabrous.

Lower glumes

0.3-0.8 mm, reduced, acute;

upper glumes and lower lemmas subequal or the glumes shorter, distinctly verrucose, with hemispheric warts;

upper florets 1.6-2 mm long, about 1 mm wide, grayish-brown, dull, minutely papillose, acute.

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.

= 36.

Panicum verrucosum

Panicum hirsutum

Distribution
from FNA
AL; AR; CT; DC; DE; FL; GA; IL; IN; KY; LA; MA; MD; MI; MO; MS; NC; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; WV
[WildflowerSearch map]
[BONAP county map]
from FNA
TX
[BONAP county map]
Discussion

Panicum verrucosum grows primarily in open, moist or wet sandy areas bordering swamps, marshes, or lakes or on roadside ditches; it also grows occasionally in open, drier woodlands. It is restricted to the eastern United States and is mostly, but not exclusively, coastal.

(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.)

Source FNA vol. 25, p. 487. FNA vol. 25.
Parent taxa Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Phanopyrum > sect. Verrucosa Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum
Sibling taxa
P. amarum, P. anceps, P. antidotale, P. bergii, P. bisulcatum, P. brachyanthum, P. bulbosum, P. capillare, P. capillarioides, P. coloratum, P. dichotomiflorum, P. diffusum, P. flexile, P. ghiesbreghtii, P. gymnocarpon, P. hallii, P. hemitomon, P. hirsutum, P. hirticaule, P. lacustre, P. miliaceum, P. mohavense, P. obtusum, P. paludosum, P. philadelphicum, P. plenum, P. psilopodium, P. repens, P. rigidulum, P. tenerum, P. trichoides, P. urvilleanum, P. virgatum
P. amarum, P. anceps, P. antidotale, P. bergii, P. bisulcatum, P. brachyanthum, P. bulbosum, P. capillare, P. capillarioides, P. coloratum, P. dichotomiflorum, P. diffusum, P. flexile, P. ghiesbreghtii, P. gymnocarpon, P. hallii, P. hemitomon, P. hirticaule, P. lacustre, P. miliaceum, P. mohavense, P. obtusum, P. paludosum, P. philadelphicum, P. plenum, P. psilopodium, P. repens, P. rigidulum, P. tenerum, P. trichoides, P. urvilleanum, P. verrucosum, P. virgatum
Synonyms P. debile
Name authority Muhl. Sw.
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