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knot grass, knotroot paspalum, thompsongrass, water finger-grass

water paspalum

Habit Plants perennial; rhizomatous or cespitose. Plants annual; aquatic, floating or rhizomatous.
Culms

5-65 cm, erect;

nodes glabrous.

4-55 cm, erect;

nodes pubescent.

Sheaths

glabrous, sparsely long pubescent distally;

ligules 1-2 mm;

blades to 14 cm long, 1.8-11.5 mm wide, flat or conduplicate, glabrous or pubescent, apices involute.

glabrous or pubescent;

ligules 1-4 mm;

blades 10-40 cm long, 8-22 mm wide, flat, glabrous or sparsely pubescent.

Panicles

terminal, usually composed of a digitate pair of branches, a third branch sometimes present below;

branches 1.4-7 cm, diverging, often arcuate;

branch axes 1.2-2.2 mm wide, winged, glabrous, margins scabrous, terminating in a spikelet.

terminal, with (7)20-70 racemosely arranged branches;

branches 1.2-9.5 cm, diverging to spreading, occasionally arcuate, disarticulating at maturity;

branch axes 0.7-1.5 mm wide, broadly winged, glabrous, margins scabrous, extending beyond the distal spikelet.

Spikelets

2.4-3.2 mm long, 1.1-1.6 mm wide, solitary (rarely paired), appressed to the branch axes, broadly elliptic, stramineous, sometimes partially purple.

1.1-1.9 mm long, 0.5-0.8 mm wide, solitary, appressed to the branch axes, elliptic, pubescent, white.

Lower glumes

absent or, if present, to 1 mm and triangular;

upper glumes sparsely and shortly pubescent on the back, 3-veined;

lower lemmas glabrous, 3-veined;

upper florets stramineous.

absent;

upper glumes and lower lemmas veinless;

upper florets white.

Caryopses

1.9-2.1 mm, yellow.

0.8-0.9 mm, translucent, white.

2n

= 20, 30, 40, 48, 60, 61.

= 20.

Paspalum distichum

Paspalum repens

Distribution
from FNA
AL; AR; AZ; CA; FL; GA; ID; KS; KY; LA; MD; MO; MS; NC; NJ; NM; NV; OK; OR; PA; SC; TN; TX; UT; VA; WA; HI; PR; Virgin Islands
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from USDA
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Discussion

Paspalum distichum grows on the edges of lakes, ponds, rice fields, and wet roadside ditches. It is native in warm regions throughout the world, being most abundant in humid areas. In the Western Hemisphere, it grows from the United States to Argentina and Chile.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Paspalum repens is a native species that grows along the edges of lakes, streams, and roadside ditches in the southeastern United States. Its range extends through tropical America to Peru, Bolivia, and Argentina.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 25, p. 575. FNA vol. 25, p. 571.
Parent taxa Poaceae > subfam. Panicoideae > tribe Paniceae > Paspalum Poaceae > subfam. Panicoideae > tribe Paniceae > Paspalum
Sibling taxa
P. acuminatum, P. almum, P. bifidum, P. blodgettii, P. boscianum, P. caespitosum, P. conjugatum, P. conspersum, P. convexum, P. coryphaeum, P. dilatatum, P. dissectum, P. fimbriatum, P. floridanum, P. hartwegianum, P. intermedium, P. laeve, P. langei, P. laxum, P. lividum, P. malacophyllum, P. minus, P. modestum, P. monostachyum, P. nicorae, P. notatum, P. paniculatum, P. pleostachyum, P. plicatulum, P. praecox, P. pubiflorum, P. quadrifarium, P. racemosum, P. repens, P. scrobiculatum, P. setaceum, P. unispicatum, P. urvillei, P. vaginatum, P. virgatum, P. virletii, P. wrightii
P. acuminatum, P. almum, P. bifidum, P. blodgettii, P. boscianum, P. caespitosum, P. conjugatum, P. conspersum, P. convexum, P. coryphaeum, P. dilatatum, P. dissectum, P. distichum, P. fimbriatum, P. floridanum, P. hartwegianum, P. intermedium, P. laeve, P. langei, P. laxum, P. lividum, P. malacophyllum, P. minus, P. modestum, P. monostachyum, P. nicorae, P. notatum, P. paniculatum, P. pleostachyum, P. plicatulum, P. praecox, P. pubiflorum, P. quadrifarium, P. racemosum, P. scrobiculatum, P. setaceum, P. unispicatum, P. urvillei, P. vaginatum, P. virgatum, P. virletii, P. wrightii
Synonyms P. paspaloides P. repens var. fluitans, P. fluitans
Name authority L. P.J. Bergius
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