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

arrocillo

Habit Plants perennial; rhizomatous or cespitose. Plants perennial; cespitose or rhizomatous.
Culms

5-65 cm, erect;

nodes glabrous.

to 100 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.

pubescent;

ligules 0.2-0.5 mm;

blades 12-35 cm long, 10-24 mm wide, flat, scabrous, pubescent near the margins, margins usually undulate.

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 18-50 racemosely arranged branches;

branches 0.8-8.9 cm, spreading to diverging, often arcuate;

branch axes 0.2-0.5 mm wide, narrowly winged, scabrous, terminating in a 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.

1.1-1.3 mm long, 0.9-1 mm wide, paired, diverging from the branch axes, ovate, light brown to stramineous.

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 pubescent, 3-veined;

upper florets 1.1-1.3 mm, stramineous.

Caryopses

1.9-2.1 mm, yellow.

0.7-0.8 mm, light brown.

2n

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

= 20, 40, 60.

Paspalum distichum

Paspalum paniculatum

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
[WildflowerSearch map]
[BONAP county map]
from FNA
MS; HI; PR; Virgin Islands
[BONAP county map]
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 paniculatum is native from Mexico and the West Indies to Argentina. It is now established in Mississippi and southern Florida, growing in disturbed areas.

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

Source FNA vol. 25, p. 575. FNA vol. 25, p. 577.
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. 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
Synonyms P. paspaloides
Name authority L. L.
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