Panicum dichotomiflorum |
Panicum flexile |
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fall panicgrass, fall panicum, knee grass, panic d'automne, smooth witchgrass |
panic flexible, wiry panic grass, wiry witch grass |
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Habit | Plants annual or short-lived perennials in the Flora region, perennial in the tropics; usually terrestrial, sometimes aquatic but not floating. | Plants annual; delicate, green or yellow-green. | ||||||||
Culms | 5-200 cm tall, 0.4-3 mm thick, decumbent to erect, commonly geniculate to ascending, rooting at the lower nodes when in water, simple to divergently branched from the lower and middle nodes, usually succulent, slightly compressed, glabrous; nodes usually swollen, sometimes constricted on robust plants, glabrous; internodes glabrous, shiny, pale green to purplish. |
10-75 cm, about 1 mm thick, simple or with erect basal branches; nodes densely pilose, hairs ascending; internodes glabrous or shortly pubescent distally. |
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Sheaths | compressed, inflated, sparsely pubescent near the base, elsewhere mostly glabrous, sparsely pilose, or hispid, hairs sometimes papillose-based, margins or throat ciliate, with papillose-based hairs; ligules 0.5-2 mm; blades 10-65 cm long, 3-25 mm wide, glabrous or sparsely pilose, often scabrous near the margins, midribs stout, whitish. |
longer than the internodes, green to purplish, hispid, margins sparsely ciliate; ligules 0.5-1.5 mm; blades 3-32 cm long, 1-7 mm wide, ascending to erect, linear, narrowing basally, flat or the margins involute, surfaces sparsely hirsute or pilose (rarely glabrous), hairs near the base papillose-based, margins prominent, apices acute. |
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Panicles | 4-40 cm, diffuse, lax, with a few spikelets; branches to 15 cm, alternate or opposite, occasionally verticillate, ascending to spreading, stiff, scabrous; pedicels 1-6 mm, sharply 3-angled, scabrous, expanded to cuplike apices, appressed mostly to the abaxial side of the branches. |
5-45 cm long, 1-6 cm wide, at least 1/2 as long as the plants and 3 times longer than wide, open; rachises glabrous; primary branches usually alternate or subopposite, ascending to slightly divergent, secondary branches and pedicels attached to the distal 2/3; secondary branches diverging; pedicels 0.5-17 mm, ascending to appressed. |
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Spikelets | 1.8-3.8 mm long, 0.7-1.2 mm wide, ellipsoid to narrowly ovoid, light green to red-purple, glabrous, acute to acuminate. |
2.5 - 3.7 mm long, 0.6-1.1 mm wide, narrowly ovoid, glabrous, acute; lower glumes 0.8-1.3 mm, 1/3 – 1/2 as long as the spikelets, acuminate; upper glumes 2.3-3.3 mm, 7-9-veined, exceeding the upper florets by about 0.6 mm; lower florets sterile; lower lemmas 2.2-2.7 mm, exceeding the upper florets by about 0.6 mm, 7- or 9-veined, apices scabridulous, pointed; lower paleas absent; upper florets 1.6-1.7 mm long, about 0.6 mm wide, usually smooth, usually pale, sometimes becoming dark at maturity. |
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Lower glumes | 0.6-1.2 mm, 1/4 - 1/3 as long as the spikelets, 0-3-veined, obtuse to acute; upper glumes and lower lemmas similar, exceeding the upper florets by 0.3-0.6 mm, 7-9-veined; lower paleas vestigial to almost as long as the lower lemmas; lower florets sterile; upper florets 1.4-2.5 mm long, 0.7-1.1 mm wide, narrowly ellipsoid, smooth, shiny, stramineous to nigrescent, with pale veins. |
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2n | = 36, 54. |
= 18. |
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Panicum dichotomiflorum |
Panicum flexile |
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Distribution |
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; HI; PR; BC; NB; NS; ON; QC
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AL; AR; CT; DC; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; ND; NJ; NY; OH; OK; PA; SC; SD; TN; TX; UT; VA; VT; WI; WV; ON; QC
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Discussion | Panicum dichotomiflorum grows in open, often wet, disturbed areas such as cultivated and fallow fields, roadsides, ditches, open stream banks, receding shores, clearings in flood plain woods, and sometimes in shallow water. It is probably native throughout the eastern United States and adjacent Canada, but introduced elsewhere, including in the western United States. Its size and habit may be partly under genetic control, but these features also seem to be strongly affected by moisture levels, soil richness, competition, and the time of germination. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Panicum flexile grows in fens and other calcareous wetlands, in dry, calcareous or mafic rock barrens, and in open woodlands, especially on limestone derived soils. It is restricted to the Flora region. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 469. | FNA vol. 25, p. 460. | ||||||||
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Dichotomiflora | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Name authority | Michx. | (Gatt.) Scribn. | ||||||||
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