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Synonyms: Wolffiaceae Bubani
Common name: Duckweed Family.
Number of genera 5. Number of species 30.
Angiosperm. Liliopsida.
Disseminule a dehisced fruit, or an intact or entire fruit, or a seed.
Fruits
Pistil(s) 1; 1-pistillate. Fruit pericarpium, or anthocarp; simple; urticle (Lemna); simple; pseudosamara (Wolffiella); without persistent central column; within accessory organ(s), or not within accessory organ(s); within perianth, or bracts; 1-seeded to more than 1 but less than 10-seeded; 1–5-seeded; less than 1 cm long; Wolffioideae 0.035–0.275 cm long (Spirodela); 1-carpellate; not sulcate; apex not beaked; wall chartaceous, or membranaceous; Lemna, Wolffia indehiscent, or dehiscent (Lemna transversely). Dehiscent and shedding seeds; without replum. Epicarp red (dish or red spotted); durable; chartaceous; glabrous (without hairs); without armature; with wing(s); 2-winged; with wing(s) lateral (& near apex); without apical respiratory hole. Mesocarp absent. Endocarp absent. Funiculus short; short without seed bearing hooks (retinacula); not persisting in fruit after seed shed.
Seeds
Aril absent. Seed minute; less than 1 mm long; 0.03–2 mm long; ovate and straight; in transection terete, or triangular, or flattened (somewhat); not bowl shaped; not nutlike; without winglike beak; without caudate appendage(s); at maturity with food reserves, or without apparent food reserves; with endosperm; without canavanine. Sarcotesta absent. Testa present; without markedly different marginal tissue; without fleshy or leathery layer over hard layer; tight; shiny; surface unsmooth, or smooth (nearly for Wolffia & Wolffiella); surface with merged raised features; surface reticulate; without crease or line separating cotyledons from hypocotyl-radicle; without notch along margin where cotyledons from hypocotyl-radicle tip approach each other; without glands; without bristles; glabrous; without wings; without collar; with operculum; colored; monochrome; white; coriaceous, or corky, or fleshy; not becoming mucilaginous when wetted; surrounding food reserve, or surrounding embryo. Hilum punctate. Raphe conspicuous; texture as testa; as long as seed. Endosperm development cellular, or helobial; scant; with starch (and other food-reserves).
Embryo differentiated from food reserve; well developed; 1 per seed; completely filling testa (no food reserve), or nearly filling testa (trace or scanty food reserve), or partially filling testa (with food reserve); at one end of seed not extending into a depression or cup; axile and centric; linear; straight; parallel to seed length; with cotyledons gradually connected to hypocotyl-radicle (if radicle present); without coleoptile; without coleorhiza; without simmondsin; without stomata; not green; with 1 cotyledon. Cotyledons one and not modified into scutellum; not circinately coiled. Hypocotyl-radicle undeveloped, or vestigial; straight; not thickened.
Distribution
Cosmopolitan. New World, Old World. North America, Middle America, South America, Europe, Africa, Asia Major, Asia Minor, southeastern Asia, Australia, Oceania.
Weed information
1 or more USA state noxious weeds.
USA states and territories with listed noxious weeds: Puerto Rico (PR), Texas (TX).
USA state and territory noxious weeds: -- Landoltia punctata (G. Mey.) Les & D. J. Crawford: USA state noxious weed: TXª.-- Lemna valdiviana Phil.: USA state noxious weed: PRª. -- Spirodela polyrhiza (L.) Schleid.: USA state noxious weed: PRª. -- Symbols: ªaquatic weed; ●terrestrial weed; °weed in seed. -- Last updated September 2008.
Listed seeds
No ASOA or ISTA listed seeds.
Accepted genera
Landoltia Les & D. J. Crawford -- Lemna L., nom. cons. prop. -- Spirodela Schleid. -- Wolffia Horkel ex Schleid., nom. cons. -- Wolffiella (Hegelm.) Hegelm.
References specific to this family
Cronquist page 1099. Landolt, E. 1986. Biosystematic investigations in the family of duckweeds (Lemnaceae), vol 2. Veröff. Geobot. Inst. E.T.H. Stiftung Rübel Zürich 71:1–495.
General references
Cronquist, A. 1981. An integrated system of classification of flowering plants, 1,262 p. Columbia University Press, New York, Dahlgren, R.M.T., H.T. Clifford and P.F. Yeo. 1985. The families of the monocotyledons, 520 pp. Springer-Verlag, Berlin, Goldberg, A. 1986 (dicots) and 1989 (monocots). Classification, evolution, and phylogeny of the familes of Dicotyledons. Smithsonian Contr. Bot. 58 for dicots (314 pp.) and 71 for monocots (74 pp.). [Goldberg's illustrations are reproduced from older publications and these should be consulted], Gunn, C.R., J.H. Wiersema, C.A. Ritchie, and J.H. Kirkbride, Jr. 1992 and amendments. Families and genera of Spermatophytes recognized by the Agricultural Research Service. Techn. Bull. U.S.D.A. 1796:1–500, LeMaout, E. and J. Decaisne. 1876. A general system of botany, 1,065 p. Longmans, Green, and Co., London, Mabberley, D.J. 1987. The plant-book, 706 p. Cambridge University Press, Cambridge, Spjut, R.W. 1994. A systematic treatment of fruit types. Mem. New York Bot. Gard. 70:1–182.
Illustrations
Poor fruit and acceptable seed illustrations. Disseminule illustration(s): fruit, or seed, or embryo. Fruit illustration(s): LeMaout & Decasine. Seed illustration(s): Landolt (1986). Embryo illustration(s): LeMaout & Decasine.
• Fruit. 1 of 3. Lemna gibba L.: fruit. • Seed. 2 of 3. Lemna gibba L.: seeds. • Embryo. 3 of 3. Lemna trisulca L.: embryo.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘J.H. Kirkbride, Jr., C.R. Gunn, and M.J. Dallwitz. 2000 onwards. Family guide for fruits and seeds: descriptions, illustrations, identification, and information retrieval. Version: 12th April 2021. delta-intkey.com’.
