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

rib paspalum

Habit Plants perennial; rhizomatous or cespitose. Plants perennial; cespitose, sometimes with short rhizomes.
Culms

5-65 cm, erect;

nodes glabrous.

90-200 cm, erect;

nodes sunken, glabrous or pubescent, brown.

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 4-5 mm, membranous, brown, acute;

blades 12-40 cm long, 8-35 mm wide, flat or conduplicate, pubescent below, glabrous above, distinctly pubescent basally.

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 8-25 racemosely arranged branches;

branches 1-8 cm, divergent to erect;

branch axes 1-1.2 mm wide, margins scabrous, terminating in a spikelet;

pedicels 0.2-0.4 and 0.5-1.2 mm long, flattened, scabrous.

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.

1.8-2 mm, paired, appressed to or divergent from the branch axes, oblong-elliptic, white to stramineous.

Glumes

absent;

lower lemmas glabrous, ribbed over the veins, sulcate between, 5-veined, margins entire;

upper lemmas as long as the lower ones, longitudinally papillose-striate, glabrous, pale-colored.

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.

Caryopses

1.9-2.1 mm, yellow.

Upper

florets white to stramineous.

2n

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

= 40, 60.

Paspalum distichum

Paspalum malacophyllum

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
FL; GA; TX
[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 malacophyllum is native from Mexico to Bolivia and Argentina. It was introduced to the southern United States for forage and soil conservation, and is now established in the southeastern United States, growing in disturbed sites at scattered locations.

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

Source FNA vol. 25, p. 575. FNA vol. 25, p. 584.
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. 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
Synonyms P. paspaloides
Name authority L. Trin.
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