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Common name: Water-chestnut Family.
Number of genera 1. Number of species 1–15.
Angiosperm. Magnoliopsida.
Disseminule an intact or entire fruit.
Fruits
Pistil(s) compound; 1; 1-pistillate; with carpels united. Fruit anthocarp; simple; pseudodrupe; without persistent central column; crowned by sepals (spinescent calyx-limb which resembles 2–4 horns); with styles(s); at apex; within accessory organ(s); within calyx; connate; persistent; hard calyx; 1-seeded; 1-seeded; originally 2-carpellate (but 1 by arrest); with carpels united; with carpels remaining united at maturity; with carpels not radiating at maturity; with carpels remaining connected at style; without sterile carpels; not sulcate; in transection flat; apex not beaked; wall woody, or leathery; indehiscent. Epicarp evanscent; membranous; glabrous (without hairs); without armature, or with armature; with horns; without armature glochidiate; smooth, or not smooth; without wing(s); without apical respiratory hole. Mesocarp absent. Endocarp present; not separating from exocarp; woody, or bony; not splitting into 1-seeded pyrenes; not smooth; with lateral horns; without operculum; without secretory cavities; with mechanism for seedling escape; without longitudinal ridges; with apical pore(s); 1-porate. Funiculus short; short without seed bearing hooks (retinacula); not persisting in fruit after seed shed.
Seeds
Aril absent. Seed larger than minute (large); not bowl shaped; not nutlike; without winglike beak; without caudate appendage(s); at maturity without food reserves, or with food reserves; with endosperm; without canavanine. Sarcotesta absent. Testa present; without markedly different marginal tissue; without fleshy or leathery layer over hard layer; tight; surface unsmooth; 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; without operculum; colored; monochrome; membranous (upper part of testa spongy); not becoming mucilaginous when wetted; surrounding embryo. Endosperm development nuclear.
Embryo differentiated from food reserve; well developed; 1 per seed; completely filling testa (no food reserve); 1 times the length of food reserve; at one end of seed not extending into a depression or cup; foliate; straight; parallel to seed length; with cotyledons abruptly connected to hypocotyl-radicle; without coleorhiza; without simmondsin; without stomata; not green; with 2 or more cotyledons. Cotyledons 2; well developed (1, other vestigial); 0.8 times length of embryo; somewhat to significantly wider than hypocotyl-radicle; 4–6 times wider than hypocotyl-radicle; thick (1 large); smooth; with apices entire; with margins separate; unequal in size; markedly unequal; not punctate dotted; one developed and the other scalelike and emerging (along with radicle and plumule) through terminal pore left by fallen style. Hypocotyl-radicle small; straight; not thickened. Plumule minute; terminal between 2 cotyledons.
Distribution
Old World. Europe, Africa, Asia Minor, southeastern Asia.
Weed information
1 or more USA state noxious weeds.
USA states and territories with listed noxious weeds: Alabama (AL), Arizona (AZ), Connecticut (CT), Florida (FL), Maine (ME), Massachusetts (MA), Minnesota (MN), New Hampshire (NH), North Carolina (NC), Oregon (OR), South Carolina (SC), Vermont (VT), Washington (WA).
USA state and territory noxious weeds: -- Trapa bicornis Osbeck: USA state noxious weed: WAª. -- Trapa natans L.: USA state noxious weed: ALª●, AZª, CTª, MAª, MEª, MNª, ORª, SCª, VTª, WAª. -- Trapa spp.: USA state noxious weed: FLª, NCª, NHª. -- Symbols: ªaquatic weed; ●terrestrial weed; °weed in seed. -- Last updated September 2008.
Listed seeds
ISTA listed seeds.
ISTA listed seeds: -- Trapa bispinosa Roxb. -- Trapa natans var. bispinosa (Roxb.) Makino = Trapa bispinosa Roxb. -- Symbols: aagricultural and vegetable seeds (Table 2A Part 1); ttree and shrub species (Table 2A Part 2); fflower, spice, herb, and medicinal seeds (Table 2A Part 3); wweed seeds. -- Last updated September 2008.
Accepted genera
Trapa L.
References specific to this family
Cronquist page 638.
General references
Baillon, H.E. 1866–95. Histoire des plantes, 13 vols. Hachette and Co., Paris, Corner, E.J.H. 1976. The seeds of Dicots, esp. vol. 2. Cambridge University Press, New York, Cronquist, A. 1981. An integrated system of classification of flowering plants, 1,262 p. Columbia University Press, New York, Gaertner, J. 1788–1805. De fructibus et seminibus plantarum. The Author, Stuttgart, 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
Acceptable fruit and seed illustrations. Cronquist has no illustration. Disseminule illustration(s): fruit, or seed, or embryo. Fruit illustration(s): LeMaout & Decaisne, Baillon, Gaertner. Seed illustration(s): Karen. Embryo illustration(s): LeMaout & Decaisne, Karen. Karen's plate number and taxon (taxa): 193: Trapa natans L. (A-B).
• Fruit. 1 of 3. Trapa natans L.: fruits. • Seed. 2 of 3. Trapa natans L.: seed. • Embryo. 3 of 3. Trapa natans 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’.
