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Pistia stratiotes

L. (1753)

This name is accepted

Kingdom: Viridiplantae Phylum: Magnoliophyta Class/Clade: Monocots Order: Alismatales Family: Araceae Genus: Pistia

water lettuce

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Description

Key Characters:

Growth Form: Free-floating, aquatic herbs.

Stems: Spreading by stolons.

Roots:

Leaves: Leaves simple. Rosulate. Blades obovate to oblong–cuneate, 3–15 cm long, 1.5–8 cm wide, broadest at apex. Apex broadly rounded to truncate or often emarginate. Base cuneate to attenuate, sessile. Surfaces villous, pale green. 5–7 conspicuous parallel veins. Petioles very short, almost absent. Stipules absent.

Flowers: Flowers in inflorescences inconspicuous, axillary; spathe white, pubescent externally, glabrous within, the tube ovoid, the limb ovate, acute at apex; spadix white, minute, included, bearing 2–8 staminate flowers and a solitary pistillate flower. Flowers unisexual, minute. Calyx absent. Corolla (petals) absent. Staminate flowers comprising 2 connate stamens. Ovary superior (pistillate flowers), 1-carpellate, 1-celled; ovules numerous, in 4–6 rows. Flowers solitary.

Fruit: Berries ovoid to ellipsoid; with persistent stigma. Seeds numerous; cylindrical; sessile.

Ploidy: 2n = 28

Habitat: Occurs in open ditches; ponds; and other watercourses; generally at low elevations.

Elevation Range:

Historical Distribution

Images

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Uses and Culture

USES

Natural History

Statewide Status

Naturalized

Island Status

Kaua'i Naturalized
O'ahu Naturalized
Molokai Naturalized
Maui Naturalized
Hawai'i Naturalized

Dispersal Agents

Water/Ocean

Vegetative Reproduction

Pollinators

Bibliography

Name Published In: Sp. Pl.: 963 (1753)

Other References

Wagner et al. 1990:1359 (K, O, Mo, M); Staples & Herbst 2005:594 (KEY), 610 (DESCR); Imada & Kennedy 2020:71 (H)

Occurrences

SNo. Scientific Name Locality Habitat Basis of Record Description Recorded By Record Number Island Source Date
1 Pistia stratiotes Kau, in a pond behind Punalu‘u Beach Covering entire pond, along with patches of water hyacinth and waterlilies (no sign of Salvinia). Preserved_Specimen Floating aquatic herbs up to 6-8 inches high. No flowers or fruit. Reproduction appears to be principally by runners (stolons). Gagné, B.H. 3154 Hawaii BISH 2006-05-04
2 Pistia stratiotes U.H. Campus, courtyard of St. John Hall Floating on water in partial shade. Preserved_Specimen Lau, J. 1192 Oahu BISH 1985-07-08
3 Pistia stratiotes Kipu Pt, above Keawanui Bay (N Molokai) Home garden, in taro patch. Preserved_Specimen Floating aquatic herb, leaves light green. Lorence, D.H. 5477 Molokai BISH 1987-08-03
4 Pistia stratiotes Kilauea UNKNOWN Molokai HAPI 12/31/1989
5 Pistia stratiotes Waialua beach, washed up by sea, probably from nearby stream Preserved_Specimen Neal, M.C. Oahu BISH 1938-01-08
6 Pistia stratiotes Honolulu, 1931A Keeaumoku St In outdoor fish pool. Preserved_Specimen Williams, F.X. Oahu BISH 1946-08-01
7 Pistia stratiotes Honolulu, University of Hawaii Manoa campus, courtyard of Krause Hall growing in lily pond. Cultivated aquatic plant, floating freely on the surface of the pond. Preserved_Specimen Rosette of lvs 3-4 Ø [diameter? from orig. label], pale green in color, softly hairy; infl nestled in center of rosette, spathe green, spadix white and yellow. Herbst, D.R. 9585 Oahu BISH 1992-04-04
8 Pistia stratiotes Honolulu: Manoa Valley; University of Hawaii Manoa Campus; courtyard of St. John Hall Floating on water in partial shade. Preserved_Specimen Lau, J. 1192 Oahu BISH 1985-07-08
9 Pistia stratiotes Kalihi Kai, Hawaii Dept. of Agriculture, Plant Quarantine Branch office. Intercepted import plant material. Preserved_Specimen Sakaino, L. Oahu BISH 2019-02-27
10 Pistia stratiotes Maui County, US-HI, US UNKNOWN Oahu HAPI 12/31/1989
11 Pistia stratiotes Kekaha, Cox drainage canal N of Kekaha Rd at its intersection w. Manu Rd Preserved_Specimen Foliage grey green. Flynn, T.W. 952 Kauai BISH 1984-11-21
12 Pistia stratiotes Honolulu, 2709 Tantalus Dr., 1st switchback above watertank UNKNOWN Oahu HAPI 12/31/1989
13 Pistia stratiotes Lihue District. Along edge of canal, next to bridge at corner of Kauai Beach Drive and Kauai Beach Road. East Kauai Floating on surface of water on margin of canal Megathyrsus maximus, Lleucaena leucocephala, Sphagneticola triloba, Schoenoplectus californicus, Ficus elastica Preserved_Specimen Light green floating aquatic perennial, forming large mats on the waters surface, clumping in places on the edge of canal. Each plant a rosette of thick, pubescent leaves, with the larger plants becoming slightly more erect, up to 20 cm. or more above the waters surface Williams, A.M. 749 Kauai BISH 2022-09-23
14 Pistia stratiotes Kaaawa In brackish water near beach. Preserved_Specimen Spathe white. Herbst, D.R. 5283 Oahu BISH 1975-04-21
15 Pistia stratiotes Mokuleia Pond. Preserved_Specimen Degener, O. 11977 Oahu BISH 1938-04-14
16 Pistia stratiotes Kawainui Marsh, Southend of dike road on Marsh side Floating on water at south end of dike road. Covering entire open water area. Preserved_Specimen Floating herbaceous plant. Mini-lettuce like whorlled leaf arrangement. Light green with light hairs, spongy texture. Hanging roots with many rootlets. New plants form on runners attached to main plant. Crago, L.M. 2005013 Oahu BISH 2005-01-20
17 Pistia stratiotes 2.5 mi E of Kihei Covering the surface of water in roadside ditch. Preserved_Specimen Lower parts of leaves thick & spongy. Fosberg, F.R. 43544 Maui BISH 1963-03-10
18 Pistia stratiotes Kau, in a pond behind Punalu‘u Beach Covering entire pond, along with patches of water hyacinth and waterlilies (no sign of Salvinia). Preserved_Specimen Floating aquatic herbs up to 6-8 inches high. No flowers or fruit. Reproduction appears to be principally by runners (stolons). Gagné, B.H. 3154 Hawaii BISH 2006-05-04
19 Pistia stratiotes U.H. Campus, courtyard of St. John Hall Floating on water in partial shade. Preserved_Specimen Lau, J. 1192 Oahu BISH 1985-07-08
20 Pistia stratiotes Kipu Pt, above Keawanui Bay (N Molokai) Home garden, in taro patch. Preserved_Specimen Floating aquatic herb, leaves light green. Lorence, D.H. 5477 Molokai BISH 1987-08-03
21 Pistia stratiotes Kilauea UNKNOWN Molokai HAPI 12/31/1989
22 Pistia stratiotes Waialua beach, washed up by sea, probably from nearby stream Preserved_Specimen Neal, M.C. Oahu BISH 1938-01-08
23 Pistia stratiotes Honolulu, 1931A Keeaumoku St In outdoor fish pool. Preserved_Specimen Williams, F.X. Oahu BISH 1946-08-01
24 Pistia stratiotes Honolulu, University of Hawaii Manoa campus, courtyard of Krause Hall growing in lily pond. Cultivated aquatic plant, floating freely on the surface of the pond. Preserved_Specimen Rosette of lvs 3-4 Ø [diameter? from orig. label], pale green in color, softly hairy; infl nestled in center of rosette, spathe green, spadix white and yellow. Herbst, D.R. 9585 Oahu BISH 1992-04-04
25 Pistia stratiotes Honolulu: Manoa Valley; University of Hawaii Manoa Campus; courtyard of St. John Hall Floating on water in partial shade. Preserved_Specimen Lau, J. 1192 Oahu BISH 1985-07-08
26 Pistia stratiotes Kalihi Kai, Hawaii Dept. of Agriculture, Plant Quarantine Branch office. Intercepted import plant material. Preserved_Specimen Sakaino, L. Oahu BISH 2019-02-27
27 Pistia stratiotes Maui County, US-HI, US UNKNOWN Oahu HAPI 12/31/1989
28 Pistia stratiotes Kekaha, Cox drainage canal N of Kekaha Rd at its intersection w. Manu Rd Preserved_Specimen Foliage grey green. Flynn, T.W. 952 Kauai BISH 1984-11-21
29 Pistia stratiotes Honolulu, 2709 Tantalus Dr., 1st switchback above watertank UNKNOWN Oahu HAPI 12/31/1989
30 Pistia stratiotes Lihue District. Along edge of canal, next to bridge at corner of Kauai Beach Drive and Kauai Beach Road. East Kauai Floating on surface of water on margin of canal Megathyrsus maximus, Lleucaena leucocephala, Sphagneticola triloba, Schoenoplectus californicus, Ficus elastica Preserved_Specimen Light green floating aquatic perennial, forming large mats on the waters surface, clumping in places on the edge of canal. Each plant a rosette of thick, pubescent leaves, with the larger plants becoming slightly more erect, up to 20 cm. or more above the waters surface Williams, A.M. 749 Kauai BISH 2022-09-23
31 Pistia stratiotes Kaaawa In brackish water near beach. Preserved_Specimen Spathe white. Herbst, D.R. 5283 Oahu BISH 1975-04-21
32 Pistia stratiotes Mokuleia Pond. Preserved_Specimen Degener, O. 11977 Oahu BISH 1938-04-14
33 Pistia stratiotes Kawainui Marsh, Southend of dike road on Marsh side Floating on water at south end of dike road. Covering entire open water area. Preserved_Specimen Floating herbaceous plant. Mini-lettuce like whorlled leaf arrangement. Light green with light hairs, spongy texture. Hanging roots with many rootlets. New plants form on runners attached to main plant. Crago, L.M. 2005013 Oahu BISH 2005-01-20
34 Pistia stratiotes 2.5 mi E of Kihei Covering the surface of water in roadside ditch. Preserved_Specimen Lower parts of leaves thick & spongy. Fosberg, F.R. 43544 Maui BISH 1963-03-10
35 Pistia stratiotes Kau, in a pond behind Punalu‘u Beach Covering entire pond, along with patches of water hyacinth and waterlilies (no sign of Salvinia). Preserved_Specimen Floating aquatic herbs up to 6-8 inches high. No flowers or fruit. Reproduction appears to be principally by runners (stolons). Gagné, B.H. 3154 Hawaii BISH 2006-05-04
36 Pistia stratiotes U.H. Campus, courtyard of St. John Hall Floating on water in partial shade. Preserved_Specimen Lau, J. 1192 Oahu BISH 1985-07-08
37 Pistia stratiotes Kipu Pt, above Keawanui Bay (N Molokai) Home garden, in taro patch. Preserved_Specimen Floating aquatic herb, leaves light green. Lorence, D.H. 5477 Molokai BISH 1987-08-03
38 Pistia stratiotes Kilauea UNKNOWN Molokai HAPI 12/31/1989
39 Pistia stratiotes Waialua beach, washed up by sea, probably from nearby stream Preserved_Specimen Neal, M.C. Oahu BISH 1938-01-08
40 Pistia stratiotes Honolulu, 1931A Keeaumoku St In outdoor fish pool. Preserved_Specimen Williams, F.X. Oahu BISH 1946-08-01
41 Pistia stratiotes Honolulu, University of Hawaii Manoa campus, courtyard of Krause Hall growing in lily pond. Cultivated aquatic plant, floating freely on the surface of the pond. Preserved_Specimen Rosette of lvs 3-4 Ø [diameter? from orig. label], pale green in color, softly hairy; infl nestled in center of rosette, spathe green, spadix white and yellow. Herbst, D.R. 9585 Oahu BISH 1992-04-04
42 Pistia stratiotes Honolulu: Manoa Valley; University of Hawaii Manoa Campus; courtyard of St. John Hall Floating on water in partial shade. Preserved_Specimen Lau, J. 1192 Oahu BISH 1985-07-08
43 Pistia stratiotes Kalihi Kai, Hawaii Dept. of Agriculture, Plant Quarantine Branch office. Intercepted import plant material. Preserved_Specimen Sakaino, L. Oahu BISH 2019-02-27
44 Pistia stratiotes Maui County, US-HI, US UNKNOWN Oahu HAPI 12/31/1989
45 Pistia stratiotes Kekaha, Cox drainage canal N of Kekaha Rd at its intersection w. Manu Rd Preserved_Specimen Foliage grey green. Flynn, T.W. 952 Kauai BISH 1984-11-21
46 Pistia stratiotes Honolulu, 2709 Tantalus Dr., 1st switchback above watertank UNKNOWN Oahu HAPI 12/31/1989
47 Pistia stratiotes Lihue District. Along edge of canal, next to bridge at corner of Kauai Beach Drive and Kauai Beach Road. East Kauai Floating on surface of water on margin of canal Megathyrsus maximus, Lleucaena leucocephala, Sphagneticola triloba, Schoenoplectus californicus, Ficus elastica Preserved_Specimen Light green floating aquatic perennial, forming large mats on the waters surface, clumping in places on the edge of canal. Each plant a rosette of thick, pubescent leaves, with the larger plants becoming slightly more erect, up to 20 cm. or more above the waters surface Williams, A.M. 749 Kauai BISH 2022-09-23
48 Pistia stratiotes Kaaawa In brackish water near beach. Preserved_Specimen Spathe white. Herbst, D.R. 5283 Oahu BISH 1975-04-21
49 Pistia stratiotes Mokuleia Pond. Preserved_Specimen Degener, O. 11977 Oahu BISH 1938-04-14
50 Pistia stratiotes Kawainui Marsh, Southend of dike road on Marsh side Floating on water at south end of dike road. Covering entire open water area. Preserved_Specimen Floating herbaceous plant. Mini-lettuce like whorlled leaf arrangement. Light green with light hairs, spongy texture. Hanging roots with many rootlets. New plants form on runners attached to main plant. Crago, L.M. 2005013 Oahu BISH 2005-01-20
51 Pistia stratiotes 2.5 mi E of Kihei Covering the surface of water in roadside ditch. Preserved_Specimen Lower parts of leaves thick & spongy. Fosberg, F.R. 43544 Maui BISH 1963-03-10
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