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Berg's panicgrass, Bergs witchgrass

Mexican panicgrass, roughstalk witchgrass, roughstalk wltchgrass, woodland panic

Habit Plants perennial; cespitose, with numerous leaves clustered at the base. Plants annual; glabrous or hispid, hairs papillose-based.
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.

11-110 cm, erect to decumbent;

nodes shortly hirsute or glabrous.

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.

shorter than the internodes, greenish to purplish, glabrous or with papillose-based hairs, ciliate on 1 margin, glabrous on the other;

collars hirsute;

ligules 1.5-3.5 mm, of hairs;

blades 3-30 cm long, 3-30 mm wide, flat, usually hirsute or sparsely pubescent, hairs papillose-based, sometimes glabrous, bases rounded to cordate-clasping, margins ciliate, cilia papillose-based, 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.

9-30 cm long, 5-8 cm wide, erect or nodding, partially included to well-exserted, rachises glabrous or sparsely hispid basally;

primary branches usually alternate to opposite, divergent, secondary branches and pedicels confined to the distal 2/3;

pulvini inconspicuous;

secondary branches appressed;

pedicels 9-27 mm, appressed.

Spikelets

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

1.9-4 mm long, 0.8-1 mm wide, ovoid to almost spherical, often reddish-brown, glabrous, veins prominent, scabridulous, apices abruptly acuminate.

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.

1.3-2.4 mm, 1/2 - 3/4 as long as the spikelets, 3-5-veined;

upper glumes 1.8-3.3 mm, 7-11-veined;

lower florets sterile;

lower lemmas similar to the upper glumes, 9-veined;

lower paleas 0.4-0.9 mm;

upper florets 1.5-2.4 mm long, 0.4-0.8 mm wide, ellipsoid, smooth or conspicuously papillate, shiny, stramineous, often with a lunate scar at the base.

2n

= 36.

Panicum bergii

Panicum hirticaule

Distribution
from FNA
AL; GA; LA; TX
[BONAP county map]
from FNA
AZ; CA; NM; NV; OK; TX; WA
[WildflowerSearch map]
[BONAP county map]
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 hirticaule grows in rocky or sandy soils in waste places, roadsides, ravines, and wet meadows along streams. Its range extends from southeastern California and southwestern Texas southward through Mexico, Central America, Cuba, and Hispaniola to western South America and Argentina.

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

Key
1. Blades rounded at the base, 3-16 mm wide; lower paleas less than 1/2 as long as the upper florets; panicles erect
subsp. hirticaule
1. Blades cordate, clasping at the base, 4-30 mm wide; lower paleas more than 1/2 as long as the upper florets; panicles often nodding.
→ 2
2. Nodes, sheaths, and blades glabrous or sparsely pilose, hairs papillose-based; culms usually less than 70 cm tall; spikelets 3.2-4 mm long
subsp. stramineum
2. Nodes, sheaths, and blades hirsute, hairs papillose-based; culms robust, usually more than 70 cm tall; spikelets 3-3.3 mm long
subsp. sonorum
Source FNA vol. 25, p. 464. FNA vol. 25, p. 460.
Parent taxa Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum
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. gymnocarpon, P. hallii, P. hemitomon, P. hirsutum, 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
Subordinate taxa
P. hirticaule subsp. hirticaule, P. hirticaule subsp. sonorum, P. hirticaule subsp. stramineum
Synonyms P. pilocomayense P. pampinosum
Name authority Arechav. J. Presl
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