Trigoniaceae A.Juss.

This family is accepted.


Miguel, J.R. & Guimarães, E.F. (2011). Neotropical Trigoniaceae.


Trees up 35m in height and 50cm DAP, and erect shrubs or flexible vines, much branched, decumbent or scandent. Leaves simple , usually opposite, rarely spiral, two-ranked or fasciculate ; sometimes glandular and/or hairy; the adaxial surface green, the abaxial white, gray, yellowish, rarely blue or green, with white indumentum ; stipules deciduous or persistent . Inflorescences axillary or terminal , of simple or complex racemes, panicles, thyrses, monochacial cymes, 2- or 3-flowered; bracts and bracteoles linear or lanceolate , pilose or tomentose , +/- glandular Flowers pedicellate, cream or red, bisexual , zygomorphic , somewhat papilionoid; calyx of 5 green sepals, unequal, hairy, +/- glandular ; corolla with 5 petals, banner petal "hunch-backed", +/- indumentum , usually with hairs only on the inner edge of the hump, two keel petals glabrous , and two spatulate petals with a tuft of hairs at the base; stamens 5-8, +/- 3-4 staminodes, anthers basifixed; ovary superior , syncarpous, tri-carpellate, 3(-1)-locular, ovules 1-numerous; style terminal , simple , stigma capitate Fruit a 3- winged samara or septicidal capsule with one to many seeds, these surrounded by silky hairs and wind-dispersed.

General Description
Notes on delimitation
  • Based on molecular data the family is resolved as monophyletic and sister to the Dichapetalaceae in the order Malphigiales along with about 40 other families (APG III 2009).
  • Historically there has been considerable divergence of opinion as to the systematic position of the Trigoniaceae (Lleras 1978).  Previously it has been placed in order Polygalales (Erdtman 1952; Cronquist 1968) or order Rutales (Engler 1954, 1964), using mainly palynological and morphological evidence.
Number of genera

3 genera:

  • Isidodendron is monotypic.
  • Trigoniodendron is monotypic.
  • Trigonia with about 30 species.
  • Native
General notes
  • The hairs around the tiny seeds have been used for stuffing pillows and cushions.
  • Trigonianivea Cambess. and Trigonia villosa Aubl. var. villosa are used as ornamentals.
  • Trigoni nivea has been used as medicine to cure kidney diseases in Paraty, Rio de Janeiro.
  • Trigonia microcarpa Sagot ex Warm. is used by indigenous people in the Amazon to increase uterine contractions in childbirth (in sched.).
Distribution in the Neotropics

The family contains five genera and c. 31 species of which three genera and c. 29 species are represented in the Neotropics.

  • Isidodendron (monotypic) - Isidodendrontripterocarpum Fern.Alonso, Pérez-Zab. & Idarraga - inhabits the primary as well as secondary tropical moist forests and altered zones of Colombia (Fernández-Alonso, Pérez & Idarraga 2000).
  • Trigoniodendron (monotypic) - Trigoniodendronspiritusanctense E.F.Guim. & MiguelE.F. Guim. & Miguel - is frequent in the coastal rain forests of Brazil (Guimarães & Miguel 1987).
  • Trigonia Aubl. (c. 30 species) - some species inhabit primary forests, while others occur as pioneer species in degraded areas (Guimarães & Miquel 1985) throughout the Neotropics.
Distinguishing characters (always present)
  • Trees, shrubs (erect or scandent) or vines.
  • Opposite or spirally arranged, simple leaves.
  • Zygomorphic, papilionoid, bisexual flowers.
  • Stamens 5-8 and staminodes 3-4 or absent; all connate in one structure.
  • Superiorovary, 3-carpellate.
  • Fruit a capsule or samara.
  • Seeds one to numerous.
Useful tips for generic identification

Key to genera of neotropical Trigoniaceae

1. Trees; leaves alternate — 2
1. Shrubs erect, scandent or vines; leaves opposite — Trigonia .

2. Fruit a globose capsule; flowers in axillary panicles, staminal ring ending in two glands; without staminodes ... Trigoniodendron
2. Fruit a samara; flowers in spikes; staminal ring devoid of glands; with 4 staminodes ...Isidodendron

Important literature

Cronquist, A. 1968.  The Evolution and Classification of Flowering Plants, pp. 274-277. Houghton Miffin, Boston.

Peterson, O.G. 1896.  Trigoniaceae. In: Engler, H.G.A. & Prantl, K.A.E. (eds.). Die Naturlichen Planzenfamilien, vol. 3, abt. 4, pp. 309-311, fig. 165-166. Wilhelm Engelmann, Leipzig .

Endlicher, S.L. 1841. Trigoniaceae. Enchiridion botanicum,  p. 570. W. Engelmann, Leipzig.

Erdtman, G. 1952.  Trigoniaceae. Pollen Morphology and Plant Taxonomy: Angiosperms, pp. 438-439. Almquist & Wiksell, Stockholm.

Fernández-Alonso, J.L., Pérez-Zabala, J.A. & Idarraga-Piedrahita, A. 2000. Isidodendron, un nuevo género neotropical de árboles de la familia Trigoniaceae. Revista da Academia colombiana de Ciencias Exatas, 34(92): 347-357.

Guimarães, E.F. & Miguel, J.R. 1985. Flora do Estado do Rio de Janeiro-família Trigoniaceae. Rodriguésia 37(63): 57-72, est.1-19c.

Guimarães, E.F. & Miguel, J.R. 1987. Contribuição ao conhecimento de Trigoniaceae Brasileiras VI. Trigoniodendron Guimarães & J. Miguel. n. gen. Rio de Janeiro, Brasil. Revista Brasileira de Biologia 47(4): 559-563, fig. 1-14.

Lleras, E. 1978. Trigoniaceae. Flora Neotropica. Monograph vol. 19, pp.1-73. + 19 figs. Organization for Flora Neotropica. New York Botanical Garden.

Miguel, J.R. & Guimarães, E.F. 2000. Trigoniaceae brasileiras XIII - Restabelecimento de um táxon e descrição de uma nova espécie. BRADEA 7(32): 197-200, 1 fig.

Warming, E. 1875. Trigoniaceae. In: Martius, C.F.P. von, Eichler, A.W. & Urban, I. (Eds.). Flora brasiliensis vol. 13, part.2, pp.118-144. t. 22-27. München, Wien, Leipzig.

Trigoniaceae A.Juss. appears in other Kew resources:

First published in Dict. Univ. Hist. Nat. 12: 670. 1849 [7 Jul 1849] (1849)

Accepted by

  • APG IV (2016)

  • Kew Names and Taxonomic Backbone

    The International Plant Names Index and World Checklist of Selected Plant Families 2022. Published on the Internet at and
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families.

  • Neotropikey

    Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.