Panicum dichotomiflorum |
Panicum repens |
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fall panicgrass, fall panicum, knee grass, panic d'automne, smooth witchgrass |
couch panicum, creeping panic, panic rampant, torpedo grass, wainaku 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 perennial; rhizomatous, forming extensive colonies, rhizomes long, to 5 mm thick, branching, scaly, sharply pointed. | ||||||||
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. |
20-90 cm tall, 1.8-2.8 mm thick, erect, rigid, simple or branching from the lower and middle nodes; nodes glabrous or sparsely hispid; internodes glabrous. |
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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. |
generally shorter than the internodes, not keeled, lower nodes glabrous or hispid, hairs papillose-based, particularly near the summits; ligules 0.5-1 mm; blades 3-25 cm long, 2-8 mm wide, often distichous, flat to slightly involute, firm, adaxial surfaces pilose basally, glabrous or sparsely pubescent abaxially. |
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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. |
3-24 cm long, usually less than 5 cm wide, open; primary branches 2-11 cm, alternate, few, stiffly ascending to spreading; pedicels 1-6 mm, subappressed. |
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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. |
2.2-2.8 mm long, 0.8-1.3 mm wide, ellipsoid-ovoid, pale green, acute, upper glumes and lower lemmas sometimes separating (gaping) beyond the florets. |
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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. |
0.5-1 mm, 1/5 – 2/5 as long as the spikelets, glabrous, faintly 1-5-veined, subtruncate to broadly acute; upper glumes and lower lemmas glabrous, extending 0.1-0.5 mm beyond the upper florets, scarcely separated; upper glumes 7-11-veined, shorter than the lower lemmas, acute to short-acuminate; lower florets staminate; lower lemmas 7-11-veined; lower paleas 1.9-2.1 mm, oblong; upper florets 1.8-2.7 mm long, 0.7-1.3 mm wide, broadly ellipsoid, broadest at or above the middle, glabrous, shiny, smooth, apices rounded. |
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2n | = 36, 54. |
- 36, 40, 45, 54. |
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Panicum dichotomiflorum |
Panicum repens |
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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; CA; FL; GA; LA; MS; NC; SC; TX; HI
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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 repens grows on open, moist, sandy beaches and the shores of lakes and ponds, occasionally extending out into or onto the water. It is mostly, but not exclusively, coastal. It grows on tropical and subtropical coasts throughout the world and may have been introduced to the Americas from elsewhere. Small plants having small, dense panicles of purplish spikelets with longer, subacute lower glumes have been named Panicum gouinii E. Fourn., but they intergrade with more typical plants and do not seem to merit taxonomic recognition. (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. | ||||||||
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Dichotomiflora | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Repentia | ||||||||
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Subordinate taxa | ||||||||||
Name authority | Michx. | L. | ||||||||
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