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(Last Modified On 10/18/2012)
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(Last Modified On 10/19/2012)
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Genus
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PANICUM
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PlaceOfPublication
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Sp. P1. 55. 1753.
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Description
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Spikelets paniculate or sometimes short-pedicelled in one-sided racemes; first glume minute to nearly as long as the spikelet; second glume and sterile lemma nearly equal, similar, the lemma often enclosing a hyaline palea and sometimes a staminate flower; fertile floret indurate, the nerves obsolete, the margins of the lemma inrolled, firmly enclosing the palea.
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Note
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Annuals or perennials, exceedingly variable in habit, size, and appearance.
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Key
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a. Basal blades distinctly different from the culm blades, forming winter rosettes; culms at first simple, finally sparingly to freely branching. b. Plants light green, the blades of the rosette forming small soft dense cushions; culms 10-20 cm. high, branching from the base; blades conspicuously ciliate - __ - - - _ - _ - 1. P. STRIGOSUM
bb. Plants dark green or olivaceous, the basal blades not forming dense soft cushions; culms 20-100 cm. high, branching from the middle and upper nodes; blades not conspicuously ciliate or only near the base. c. Ligule obsolete or nearly so; blades glabrous or nearly so with firm, white margins, ciliate near the base; culms sparingly branch- ing -------- - ---- --- _ _____ _________ 2. P. SPHAEROCARPON
cc. Ligule 2-4 mm. long, ciliate; blades densely pubescent or villous; culms finally freely branching, the blades and panicles of the branches reduced. d. Blades velvety-pubescent; spikelets 1.8-1.9 mm. long; culms mostly more than 70 cm. long from a creeping base -3. P. VISCIDELLUM
dd. Blades not velvety; spikelets 1.9-2 mm. long; culms less than 5 0 cm. long _ - _ _--- __ 4. P. OLIVACEUM
aa. Basal blades similar to the culm blades.
b. Plants annual.
c. Fruit transversely rugose; spikelets short-pedicelled along the raceme-like branches. d. Spikelets glabrous, brown, 2.5-3 mm. long -_ - 7. P. FASCICULATUM
dd. Spikelets densely pubescent, 3.5-4 mm. long - _ - _ 8. P. MOLLE
cc. Fruit smooth; spikelets in open panicles. d. First glume one-fourth as long as the spikelet, obtuse or sub- acute. Glabrous, rather succulent, subaquatic annual - 9. P. CHLOROTICUM
dd. First glume at least half as long as the spikelet.
e. Culms erect; spikelets at least 2 mm. long; blades elongate.
f. Culms robust, 1.5 m. or more high; spikelets 2 mm. long- 12. P. HIRSUTUM
ff. Culms slender, not more than 75 cm. high.
g. Spikelets 2.2 mm. long; panicles terminal and axillary, crowded, implicate - - _ - 11. P. CAYENNENSE
gg. Spikelets 2.5-3.3 mm. long; panicles not implicate - 10. P. HIRTICAULE
ee. Culms decumbent-spreading; spikelets 1.5 mm. long; blades ovate or elliptic. f. Panicles 2-5 cm. long, with delicate flexuous, spreading or reflexed branches; spikelets pyriform, glabrous- 25. P. PYRULARIUM
ff. Panicles 5-20 cm. long, the branches delicate but not flexuous, ascending to spreading; spikelets elliptic, pubes- cent _ - _ _ - _ - _ - _ - 27. P. TRICHOIDES
bb. Plants perennial. c. Spikelets short-pedicellate along one side of the panicle branches, forming spike-like or 1-sided racemes. d. Fruit transversely rugose.
e. Culms slender, less than 1 m. long; nodes glabrous- - 5. P. GEMINATUM
ee. Culms coarse, as much as 6 m. long; nodes bearded - 6. P. PURPURASCENS dd. Fruit smooth, not rugose. e. Blades lanceolate or ovate-lanceolate.
f. Spikelets sparsely pilose, the sterile lemma with two crateri- form glands on the back - -- - 16. P. PULCHELLUM
ff. Spikelets glabrous, glandless. g. Blades 1-5 cm. long; racemes few to several, scarcely crowded ----- - - - - - 17. P. STOLONIFERUM
gg. Blades 5-11 cm. long; racemes numerous, crowded - 18. P. FRONDESCENS
ee. Blades linear, often elongate, frequently cordate at the base.
f. Spikelets nearly sessile, densely arranged along one side of the pilose rachis.
g. Culms as much as 2 m. high; panicles 25-45 cm. long 19. P. MILLEFLORUM
gg. Culms not more than 1 m. high; panicles 5-15 cm. long. 20. P. PILOSUM
ff. Spikelets in part on short branchlets on the lower side of the rachis. g. Blades 20-25 cm. long, 1.5-3 cm. wide; panicles 20-40 cm. long _- - _ - _ -24. P. STAGNATILE
gg. Blades not more than 15 cm. long; panicles 5-30 cm. long.
h. Nodes pubescent - - _ - _ ___21. P. POLYGONATUM
hh. Nodes glabrous. i. Blades narrowed toward the base -22. P. LAXUM
ii. Blades somewhat cordate at the base - -- 23. P. BOLIVIENSE
cc. Spikelets in open or contracted panicles but not on 1-sided racemes.
d. Fruit transversely rugose. Culms in large coarse clumps-- 36. P. MAXIMUM
dd. Fruit not rugose.
e. First glume much less than one-fourth as long as the spikelet.
f. Sheaths glabrous on the back, densely pubescent on the collar; panicles mostly 4-8 cm. long; blades 5-12 mm. wide 30. P. ARUNDINARIAE
ff. Sheaths pilose or papillose-pilose; panicles 10-15 cm. long; blades 1-2.5 cm. wide - - __ - __ - - 31. P. SCHIFFNERI
ee. First glume more than one-fourth as long as the spikelet.
f. Blades as much as 1 m. long and 6 cm. wide- 38. P. GRANDE
ff. Blades much smaller. g. Fruit crested at the apex. Spikelets 5.5-6 mm. long- 39. P. ZIZANIOIDES
gg. Fruit not crested.
h. Panicles narrow and few-flowered. Culms erect, wiry- 34. P. STENODOIDES
hh. Panicles many-flowered. i. Panicles 40-60 cm. long, the elongate branches in verticils _ - _ - _-- 37. P. MERTENSII
ii. Panicles not more than 30 cm. long, the branches not in verticils.
j. First glume blunt or rounded, seldom subacute, two-thirds as long as the spikelet or more.
k. Spikelets 2 mm. long; panicles all alike, 10- 20 cm. long- - _ 29. P. SELLOWII
kk. Spikelets 2.7-3.5 mm. long; primary panicles open, the secondary narrow, reduced, partly enclosed in the sheath. 1. Plant glabrous or the blades sparsely pilose.32. P. CORDOVENSE
11. Plants velvety pubescent _ - _ 33. P. PANTRICHUM
jj. First glume acute or acuminate, not more, usually less, than two-thirds as long as the spikelet.
k. Spikelets 1.2-1.5 mm. long, the first glume one-fifth as long as the spikelet- 28. P. TRICHANTHUM kk. Spikelets 2.3-4 mm. long.
I. Culms erect, or finally spreading. m. Spikelets glabrous. n. Spikelets 3 mm. long; sheaths promi- nently papillose-hispid -13. P. GHIESBREGHTII
nn. Spikelets 3.5-4 mm. long; sheaths gla- brous -14. P. RIGIDUM
m. Spikelets sparsely hispid. Panicles termi- nal and axillary, implicate, partly en- closed in the sheath -15. P. RUDGEI
ll. Culms straggling.
m. Culms coarse and stout, 2-4 m. long; spikelets 3.2-4 mm. long, glabrous, turgid, gaping; first glume about two-thirds as long as the spikelet- 3 5. P. ALTUM
mm. Culms slender, mostly about 1 m. long; spikelets 2.3-2.5 mm. long, sparsely pilose; first glume about half as long as the spikelet-- 26. P. 5IAENKEANUM
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