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Common name: Water-nymph Family.
Number of genera 1. Number of species 35.
Angiosperm. Liliopsida.
Disseminule an intact or entire fruit.
Fruits
Pistil(s) simple; 1; 1-pistillate. Fruit pericarpium; simple; achene (although fruit when viable not dry, but wet so technically not a dry achene or nutlet); without persistent central column; not within accessory organ(s); 1-seeded; 1-seeded; less than 1 cm long; 0.2–0.26 cm long; 1-carpellate; not sulcate; in transection terete; apex beaked; apex moderately beaked; wall chartaceous (assumed for very thin); indehiscent. Epicarp yellow to white; dull; evanscent; chartaceous; glabrous (without hairs); without armature; smooth, or not smooth; reticulate; without wing(s); 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 larger than minute; C-shaped, or elliptic, or fusiform, or obovate, or ovate, or straight; in transection terete; 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 smooth, or unsmooth; surface with depressed features, or discreet raised features, or merged raised features; surface pitted; surface papillate; 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; without operculum; colored; monochrome; brown (all shades); hard (& brittle); not becoming mucilaginous when wetted; surrounding embryo. Raphe conspicuous, or inconspicuous (assumed); texture as testa; shorter than seed; included in dehisced fruit. Endosperm development nuclear, or helobial, or cellular.
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; linear; straight; parallel to seed length; with cotyledons gradually connected to hypocotyl-radicle; without coleoptile; without coleorhiza; without simmondsin; without stomata; not green; with 1 cotyledon. Cotyledons one and terminal with lateral plumule (& oblique); not modified into scutellum; not circinately coiled. Hypocotyl-radicle well developed; 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: Alabama (AL), Connecticut (CT), Maine (ME), Massachusetts (MA), New Hampshire (NH), Puerto Rico (PR), South Carolina (SC), Washington (WA).
USA state and territory noxious weeds: -- Najas guadalupensis (Spreng.) Magnus: USA state noxious weed: PRª. -- Najas marina L.: USA state noxious weed: ALª●. -- Najas minor All.: USA state noxious weed: CTª, MAª, MEª, NHª, SCª, WAª. -- Symbols: ªaquatic weed; ●terrestrial weed; °weed in seed. -- Last updated September 2008.
Listed seeds
No ASOA or ISTA listed seeds.
Accepted genera
Najas L.
References specific to this family
Cronquist page 1067. Haynes. R.R. 1979. Revision of North and Central American Najas (Najadaceae). Sida 8(1):34–56; Wentz, W.L. & R.R. Haynes. 1973. Family 3B. Najadaceae. In: R.E. Woodson, Jr., R.W. Schery & collaborators, Flora of Panama. Ann. Missouri Bot. Gard. 60:1–5; Lowden, R.M. 1986. Taxomony of the genus Najas L. (Najadaceae) in the Neotropics. Aquatic Bot. 24:147–184.
General references
Baillon, H.E. 1866–95. Histoire des plantes, 13 vols. Hachette and Co., Paris, Cronquist, A. 1981. An integrated system of classification of flowering plants, 1,262 p. Columbia University Press, New York, 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. and C.A. Ritchie. 1988. Identification of disseminules listed in the Federal Noxious Weed Act. Techn. Bull. U.S.D.A. 1719:1–313, 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, 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): Baillon [see Goldberg]. Seed illustration(s): Haynes (1979), Gunn & Ritchie, Karen. Embryo illustration(s): Karen, Gunn & Ritchie. Karen's plate number and taxon (taxa): 329: Najas graminea Delile (A-B).
• Fruit. 1 of 3. Najas marina L.: fruit. • Seed. 2 of 3. Najas marina L.: seed. • Embryo. 3 of 3. Najas flexilis (Willd.) Rostk. & W. L. E. Schmidt: 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’.
