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Berg's panicgrass, Bergs witchgrass

Habit Plants perennial; cespitose, with numerous leaves clustered at the base. Plants perennial; forming extensive colonies by their long, decumbent, sprawling basal branches and stolons.
Culms

(10)50-140 cm, stout, stiffly erect, branched from the middle and lower nodes;

lower nodes sericeous;

lower internodes sericeous, hairs papillose-based, upper internodes sometimes glabrous.

60-130 cm, thick, glabrous, rooting profusely at the lower nodes;

nodes glabrous, often with a dark green band.

Sheaths

rounded, glabrous or sparsely to densely hispid, hairs not fragile and prickly, not causing skin irritation, margins ciliate;

ligules 1-3 mm;

blades 3-60 cm long, 2-12 mm wide, flat or involute, ascending, adaxial surfaces densely hirsute basally, less densely so elsewhere, bases attenuate, apices acute.

usually shorter than the internodes, glabrous, prominently veined;

ligules 0.5-1.5 mm;

blades 15-40 cm long, 7-25 mm wide, tapering from midlength, flat, both surfaces glabrous, bases subcordate, margins scabrous to smooth, widest at the base, apices acute.

Panicles

(4)15-40 cm long, (3)10-25 cm wide, about 1/3 – 1/2 as long as the plants, open, breaking at the base of the peduncles at maturity and dispersed as tumbleweeds, secondary branching mostly confined to the distal 1/3 of the primary branches;

rachises densely hispid or glabrous;

lower primary branches in whorls of 4-7, stiffly spreading, naked on the lower 1/2;

pedicels 3-20 mm, appressed.

10-40 cm long, 7-20 cm wide, open, with straight, rigid rachises;

branches whorled, stiffly ascending, with short, appressed, higher order branches; ultimate branchlets 1-sided, with solitary spikelets or small clusters of spikelets;

pedicels 0.1-1.5 mm.

Spikelets

2-3 mm long, 0.8-1.2 mm wide, glabrous.

5.5-7 mm long, about 1 mm wide, narrowly lanceoloid, glabrous.

Glumes

spreading apart at maturity, keeled, prominently veined, scabrous along the midveins;

lower glumes nearly as long as the lower lemmas;

upper glumes and lower lemmas 3-veined, spreading, greatly exceeding the upper florets, lower lemmas longer than the upper glumes, arcuate;

lower florets sterile;

lower paleas thin;

upper florets 1.9-2.2 mm, less than 1/3 as long as the spikelets, obovoid, lustrous, pale to brownish, acute, often short-stipitate.

Lower glumes

1-1.6 mm, 5-veined, acuminate;

upper glumes and lower lemmas similar, 2-2.8 mm, 7-9-veined, exceeding the upper florets by about 0.3 mm;

lower florets sterile;

lower paleas 1.4-2.2 mm;

upper florets 1.5-1.9 mm long, 0.7-1 mm wide, smooth, chestnut brown at maturity.

2n

= 36.

= 40.

Panicum bergii

Panicum gymnocarpon

Distribution
from FNA
AL; GA; LA; TX
[BONAP county map]
from USDA
Discussion

Panicum bergii is an eastern South American species that now grows in southeastern Texas. It occurs in ditches and shallow, and sporadically flooded depressions in grasslands.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Panicum gymnocarpon grows in swamps, wet woodlands, and the marshy shores of lakes and streams. It is also found occasionally in shallow water, often in the shade. It is restricted to the United States.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 25, p. 464. FNA vol. 25, p. 485.
Parent taxa Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Phanopyrum > sect. Phanopyrum
Sibling taxa
P. amarum, P. anceps, P. antidotale, 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. verrucosum, 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. 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. verrucosum, P. virgatum
Synonyms P. pilocomayense Phanopyrum gymnocarpon
Name authority Arechav. Elliott
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