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rib paspalum

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

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

90-200 cm, erect;

nodes sunken, glabrous or pubescent, brown.

5-65 cm, erect;

nodes glabrous.

Sheaths

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.

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.

Panicles

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.

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.

Spikelets

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

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.

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

= 40, 60.

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

Paspalum malacophyllum

Paspalum distichum

Distribution
from FNA
FL; GA; TX
[BONAP county map]
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]
Discussion

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.)

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.)

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