Panicum amarum |
Panicum philadelphicum |
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bitter beachgrass, bitter panicgrass, bitter panicum |
panic de philadelphie, Philadelphia panic grass, Philadelphia witchgrass |
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Habit | Plants perennial; rhizomatous, rhizomes stout, glabrous and glaucous throughout. | Plants annual; hirsute, hairs papillose-based, usually yellow-green to green, sometimes purplish. | ||||||||||||
Culms | 20-250 cm tall, 3-10 mm thick, erect or decumbent, simple or branched from the lower nodes; nodes glabrous; internodes glabrous, glaucous. |
8-100 cm tall, about 1 mm thick, erect to decumbent, simple to profusely branched; nodes sparsely to densely pilose. |
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Sheaths | shorter or longer than the internodes, not keeled, glabrous; collars often glaucous and purplish; ligules 1-5 mm; blades 7-50 cm long, 2-13 mm wide, erect or ascending, firm, thick, flat basally, more or less involute towards the apices. |
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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 | 10-80 cm long, 2-17 cm wide, contracted, slightly nodding; primary branches whorled or opposite, strongly ascending to appressed; pedicels 0.5-15 mm, appressed to slightly divergent. |
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. |
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Spikelets | 4-7.7 mm long, 1.5-2 mm wide, narrowly ovoid, glabrous, acuminate; lower florets staminate. |
1.4-2.4 mm long, 0.5-0.7 mm wide, usually green, glabrous. |
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Glumes | and lower lemmas relatively thick; lower glumes 2.8-4 mm, 1/2 - 4/5 as long as the spikelets, 3-9-veined, apices of the midveins sometimes scabridulous; upper glumes and lower lemmas extending 1.5-3 mm beyond the upper florets, apices stiffly gaping; upper glumes 3.9-7.6 mm, 5-9-veined; lower lemmas slightly shorter than the upper glumes, 7-9-veined, lower paleas 3-7 mm, oblong-hastate, folded over the anthers; lower florets staminate; upper florets 2.4-3.9 mm long, 1-1.8 mm wide, narrowly ovoid to oblong, glabrous, smooth, shiny, lemma margins clasping the paleas only at the base. |
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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. |
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2n | = 36, 54. |
= 18. |
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Panicum amarum |
Panicum philadelphicum |
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Distribution |
AL; CT; DE; FL; GA; LA; MA; MD; MS; NC; NJ; NM; NY; PA; RI; SC; TX; VA; WV
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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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Discussion | Panicum amarum grows in the coastal dunes, wet sandy soils, and the margins of swamps, along the Atlantic Ocean and the Gulf of Mexico from Connecticut to northeastern Mexico. It is also known, as an introduction, from a few inland locations in New Mexico, North Carolina, and West Virginia, as well as in the Bahamas and Cuba. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
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Key |
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Source | FNA vol. 25, p. 472. | FNA vol. 25, p. 459. | ||||||||||||
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Repentia | Poaceae > subfam. Panicoideae > tribe Paniceae > Panicum > subg. Panicum > sect. Panicum | ||||||||||||
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Subordinate taxa | ||||||||||||||
Synonyms | P. tuckermanii | |||||||||||||
Name authority | Elliott | Bernh. ex Trin. | ||||||||||||
Web links |