Trapaceae

Trapaceae Dumortier

Common name: Water-chestnut Family.

Number of genera: 1 genus.

Number of species (Mabberley 1997): 1–15 species.

Disseminule type: Fruit (intact or entire).

Division: Angiosperm.

Class: Magnoliopsida.

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; with 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 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 & 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.

General distribution: Old World.

Detailed distribution: Europe, Africa, Asia Minor, and Asia Southeastern.

Noxious weeds: 1 or more USA state noxious weeds in this family.

USA states and territories with listed noxious weeds: Alabama, Arizona, Florida, Maine, Minnesota, New Hampshire, North Carolina, Oklahoma, Oregon, South Carolina, Vermont, and Washington.

USA state and territory noxious weeds:

Trapa natans L.: USA state noxious weed: ALª, AZª, MEª, MNª, NHª, OKª, ORª, SCª, VTª, WAª.

Trapa spp.: USA state noxious weed: FLª, NCª●.

Symbols: ªaquatic weed; ●terrestrial weed; °weed in seed.

Last updated February 2006.

Accepted Genera: Trapa L.

General references: Baillon, H.E. 1866–95. Histoire des plantes, 13 vols. Hachette & 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) & 1989 (monocots). Classification, evolution, and phylogeny of the familes of Dicotyledons. Smithsonian Contr. Bot. 58 for dicots (314 pp.) & 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, & J.H. Kirkbride, Jr. 1992 & amendments. Families and genera of Spermatophytes recognized by the Agricultural Research Service. Techn. Bull. U.S.D.A. 1796:1–500, LeMaout, E. & J. Decaisne. 1876. A general system of botany, 1,065 p. Longmans, Green, & Co., London, Mabberley, D.J. 1987. The plant-book, 706 p. Cambridge University Press, Cambridge, and Spjut, R.W. 1994. A systematic treatment of fruit types. Mem. New York Bot. Gard. 70:1–182.

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Suggested citation: Kirkbride, J.H., Jr., C.R. Gunn, and M.J. Dallwitz. 2006. Family Guide for Fruits and Seeds, vers. 1.0. URL: http://nt.ars-grin.gov/sbmlweb/OnlineResources/frsdfam/Index.cfm. Accessed February 9, 2010.

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