Pistia stratiotes

Linnaeus

Sp. Pl. 2: 963. 1753.

Common names: Water-lettuce
Illustrated
Synonyms: Pistia spathulata Michaux
Treatment appears in FNA Volume 22.

Roots to 50 cm, with short branches. Leaves light green to grayish green, 2–15 (–20) cm, spongy, pubescence dense, white; major veins 5–13 (–15), nearly parallel, abaxially prominent. Inflorescences: spathe white to pale green, convolute basally, slightly constricted above middle, spreading apically, pwhite to pale green, pubescent outside, glabrous inside; spadix adnate to spathe more than 1/2 its length, shorter than spathe; axis naked at base of staminate part and sometimes extending beyond staminate flowers. Flowers: staminate flowers (2–) 6–8, in single whorl around central stalk, stamens 2, connate; pistillate flower solitary; ovariesy 1-locular, 4–5 mm; ovules 4–15 (–20), orthotropous; styles ca. 3 mm; stigmas obtuse, with small hairs.; staminate flowers (2–) 6–8, in single whorl around central stalk; stamens 2, connate. Fruits with thin pericarp. Seeds light-brown, cylindric, 2 × 1 mm. 2n = 28 (India, Borneo).


Phenology: Flowering mainly late summer–early winter (although; plants have been collected in flower in almost all months).
Habitat: Slow-moving streams, canals, drainage ditches, ponds, lakes, and springs
Elevation: 0–10 m

Distribution

V22 173-distribution-map.jpg

Fla., La., Tex., Mexico, West Indies, Central America, South America, Asia, Africa, Pacific Islands, Australia

Discussion

Pistia stratiotes has been collected north and west of its U.S. range in Arizona, California, Georgia, Missouri, New Jersey, Ohio, and South Carolina. These are probably populations that do not persist. Although P. stratiotes is often reported as occurring from Florida to Texas, I saw no verifying herbarium specimens from Alabama or Mississippi, nor were any populations located during my fieldwork in those states.

Selected References

None.

Lower Taxa

None.
... more about "Pistia stratiotes"
Sue A. Thompson +
Linnaeus +
rounded;obtuse +
not peltate +  and simple +
pinnate or palmate-netted +  and parallel +
light green +  and grayish green +
obovate;spatulate +
1.5 cm15 mm <br />0.015 m <br /> (?) +
Water-lettuce +
underground +
Fla. +, La. +, Tex. +, Mexico +, West Indies +, Central America +, South America +, Asia +, Africa +, Pacific Islands +  and Australia +
0–10 m +
staminate +  and pistillate +
unisexual +  and female +
0.4 cm4 mm <br />0.004 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
brown +  and green +
connate +  and distinct +
Slow-moving streams, canals, drainage ditches, ponds, lakes, and springs +
sessile;subsessile +
clustered +, alternate +  and solitary +
15 cm150 mm <br />0.15 m <br /> (20 cm200 mm <br />0.2 m <br />) +
white;light green;grayish green +
2 cm20 mm <br />0.02 m <br /> (15 cm150 mm <br />0.15 m <br />) +
orthotropous +
Flowering mainly late summer–early winter (although +  and plants have been collected in flower in almost all months). +
horizontal +  and vertical +
0 cm0 mm <br />0 m <br /> (50 cm500 mm <br />0.5 m <br />) +
2 cm20 mm <br />0.02 m <br /> (?) +
4 +  and 10 +
cylindric +
1 cm10 mm <br />0.01 m <br /> (?) +
ovoid +  and cylindric +
pale green +  and white +
deciduous +  and persistent +
/2 +  and 1 +
glabrous +  and pubescent +
constricted +
Illustrated +
embedded in spadix +  and sessile +
discoid +  and capitate +
3 cm30 mm <br />0.03 m <br /> (?) +
Pistia spathulata +
Pistia stratiotes +
species +
plant +  and herb +
floating +  and emergent +