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Common name: Trigonia Family.
Number of genera 4. Number of species 26.
Angiosperm. Magnoliopsida.
Disseminule a dehisced fruit, or an intact or entire fruit, or a seed.
Fruits
Pistil(s) compound; 1; 1-pistillate; with carpels united. Fruit pericarpium; simple, or schizocarp; capsule, or samara (Humbertiodendron); samarium (Trigoniastrum); ceratium capsule, or septicidal capsule (Trigonia); capsule not inflated; capsule without operculum; without persistent central column; not within accessory organ(s); more than 1 but less than 10-seeded; 2-seeded (to several); 3(–4)-carpellate; 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; apex not beaked; dehiscent, or indehiscent. Dehiscent unit seed(s). Dehiscent regularly; at apex; and shedding seeds; without replum, or with replum (Trigonia eriosperma (Lam.) Fromm & E.Santos); fruit without centered partition attached to replum. Epicarp durable; glabrous (without hairs); without armature; without wing(s), or with wing(s) (Humbertiodendron & Trigoniastrum); without apical respiratory hole. Mesocarp present, or absent. Endocarp present; not separating from exocarp; thin; not splitting into 1-seeded pyrenes; smooth; without wing; without operculum; without secretory cavities; without mechanism for seedling escape; without grooves; without longitudinal ridges. Funiculus short; short without seed bearing hooks (retinacula); not persisting in fruit after seed shed.
Seeds
Aril absent. Seed not bowl shaped; not nutlike; without winglike beak; without caudate appendage(s); at maturity with food reserves, or without 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; surface unsmooth; surface with discreet raised features; surface papillate; 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, or pubescent (Trigonia); with hairs over surface; with very long hairs; densely hairy; with curly hairs; pilose; without glandular pubescence; without wings, or with wing(s) (Humberiodendron & Trigoniastrum); without collar; without operculum; colored; monochrome; membranous, or coriaceous; not becoming mucilaginous when wetted; surrounding embryo, or surrounding food reserve. Endosperm scant; fleshy (Trigonia); smooth; without fatty acid containing cyclopropene; without apical lobes; without chlorophyll; without isodiametric faceted surface; without odor.
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); 0.8–0.9 times the length of food reserve; at one end of seed not extending into a depression or cup; axile and centric; foliate; with spatulate cotyledons; straight; parallel to seed length, or transverse to seed length; embedded in endosperm; without coleorhiza; without simmondsin; without stomata; not green; with 2 or more cotyledons. Cotyledons 2; tiny; 0.8–8.5 times length of embryo; somewhat to significantly wider than hypocotyl-radicle; 5–7 times wider than hypocotyl-radicle; not concealing hypocotyl-radicle; foliaceous; thin; flat; smooth, or wrinkled (& convolute); with apices entire; with margins separate; basally entire; equal in size; not punctate dotted. Hypocotyl-radicle vestigial, or small; straight; not thickened.
Distribution
Old World. Middle America, South America, Africa (Madagascar: Humbertiodendron), southeastern Asia (Malay Peninsula, Borneo, Sumatra: Trigoniastrum).
Weed information
No USA noxious weeds.
Listed seeds
No ASOA or ISTA listed seeds.
Accepted genera
Humbertiodendron Leandri -- Trigonia Aubl. -- Trigoniastrum Miq., nom. cons. -- Trigoniodendron E. F. Guim. & Miguel
References specific to this family
Cronquist page 772. Boesewinkel, F.D. 1987. Ovules and seeds of Trigoniaceae. Acta Bot. Neerl. 36: 81–91; Guimarães, E.L. & J.R. Miguel. 1987. Contribuição ao conhecimento de Trigoniaceae brasileiras. VI - Trigoniodendron Guimarães et J. Miguel n. gen. Revista Brasil. Biol. 47:559–563.
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, Engler, A. and K. Prantl. 1924 and onward. Die Natürlichen Pflanzenfamilimien. W. Engelman, Leipzig, 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, 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, Mirle, C. and R.J. Burnham. 1999. Identification of asymmetrically winged samaras from the Western Hemisphere. Brittonia 51:1–14.
Illustrations
Poor fruit and acceptable seed illustrations. Cronquist has no illustration. Disseminule illustration(s): fruit, or seed, or embryo. Fruit illustration(s): Engler & Prantl, Boesewinkel (1987). Seed illustration(s): Baillon, Karen. Embryo illustration(s): Boesewinkel (1987), Karen. Karen's plate number and taxon (taxa): 244: Humbertiodendron soboureaui Leandri [not finalized], Trigonia nivea Cambess. (A-B), Trigoniastrum hypoleucum Miq. (C-D).
• Fruit. 1 of 6. Trigonia nivea Cambessedes: fruit. • Seed. 2 of 6. Trigonia nivea Cambessedes: seed. • Seed. 3 of 6. Trigonia nivea Cambessedes: seed with most haris removed. • Fruit. 4 of 6. Trigoniastrum hypoleucum Miq.: fruit. • Embryo. 5 of 6. Trigonia nivea Cambessedes: embryo. • Embryo. 6 of 6. Trigoniastrum hypoleucum Miq.: 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’.
