Panicum philadelphicum |
Panicum mohavense |
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panic de philadelphie, Philadelphia panic grass, Philadelphia witchgrass |
Mohave witchgrass, Mojave panicgrass |
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Habit | Plants annual; hirsute, hairs papillose-based, usually yellow-green to green, sometimes purplish. | Plants annual. | ||||||||
Culms | 8-100 cm tall, about 1 mm thick, erect to decumbent, simple to profusely branched; nodes sparsely to densely pilose. |
2-8 cm, erect-spreading; nodes 1-2, hispid; internodes pilose, hairs papillose-based. |
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Sheaths | rounded, much longer than the internodes, with prominent veins, hispid, hairs papillose-based; ligules 0.2-0.4 mm, membranous, ciliate; blades 1-4 cm long, 1-3 mm wide, flat or involute apically, glabrous basally, margins ciliate, cilia papillose-based. |
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Leaves | often crowded basally; sheaths rounded, usually longer than the internodes, hispid, hairs papillose-based, to 5 mm; ligules 0.5-1.5 mm; blades 3-30 cm long, 2-12 mm wide, linear, ascending to erect, flat, hirsute to sparsely pilose, greenish or purplish, bases truncate to subcordate and ciliate on the margins, apices acute. |
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Panicles | 7-27 cm long, 4-24 cm wide, 1/4 - 1/3 as long as the plants, diffuse, usually exserted at anthesis, not breaking at the base of the peduncles to become a tumbleweed; rachises glabrous or sparsely pilose basally; primary branches spreading, secondary branches and pedicels confined to the distal 2/3 secondary branches diverging to appressed, with 1-4 spikelets; pedicels 3-15 mm, spreading to appressed, scabrous or hirsute; pulvini glabrous or pilose. |
congested, partially included in the sheaths, less than 1.5 times longer than wide; branches ascending, narrow; primary branches appressed to the main axes, secondary branches and pedicels attached to the distal 2/3; pedicels appressed, 1-2 mm. |
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Spikelets | 1.4-2.4 mm long, 0.5-0.7 mm wide, usually green, glabrous. |
2-2.2 mm long, 1-1.3 mm wide, plump-ellipsoid, glabrous. |
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Lower glumes | 0.5-0.9 mm, usually less than 1/2 as long as the spikelets, 3-4-veined, truncate to acuminate; upper glumes 1.6-2 mm, 7-veined, veins not prominent; lower lemmas 1.6-1.9 mm, 7-9-veined, veins not prominent; lower paleas absent; lower florets sterile; upper florets 1.5-1.7 mm long, about 0.4 mm wide, often dark brown, sometimes disarticulating, apices minutely papillose. |
1.2-1.3 mm, acute to attenuate; upper glumes and lower lemmas 2-2.2 mm, 7-9-veined, apices purplish, acute; lower florets sterile; lower paleas 0.2-0.4 mm; upper florets 1.4-1.8 mm long, about 1 mm wide, broadly ovoid. |
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2n | = 18. |
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Panicum philadelphicum |
Panicum mohavense |
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Distribution |
AL; AR; CT; DC; DE; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; NC; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WI; WV; NB; NS; ON; QC
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AZ; NM |
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Discussion | Panicum philadelphicum grows in open areas such as fallow fields, roadside ditches, receding shores, and rock crevices. It is restricted to the eastern part of the Flora region. It intergrades with P. capillare, possibly as a result of hybridization, especially in the southeastern United States. Seeds germinating on receding shores in late summer often produce tiny plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Panicum mohavense is known only from arid limestone terraces in Arizona and New Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 459. | FNA vol. 25, p. 462. | ||||||||
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum | ||||||||
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Subordinate taxa | ||||||||||
Synonyms | P. tuckermanii | |||||||||
Name authority | Bernh. ex Trin. | Reeder | ||||||||
Web links |