Neotropical Turneraceae

María Mercedes Arbo

Instituto de Botánica del Nordeste (CONICET-UNNE), Corrientes, Argentina. 


Herbs, subshrubs, shrubs, treelets or rarely trees, stems erect or decumbent, frequently with serial axillary buds; hairs generally present, simple, stellate or porrect-stellate; glandular hairs often present. Stipules generally small or wanting, sometimes developed. Leaves alternate, simple, often bearing extrafloral nectaries at apex of petiole or base of blade margin, rarely abaxial; blades entire, margins entire, crenate, or toothed, not often pinnately cleft. Inflorescences axillary or terminal, cymose or racemose, usually of solitary flowers, sometimes epiphyllous by adnation of peduncle and petiole; 2 bracteoles generally subtending flowers. Flowers actinomorphic, bisexual, ephemeral, frequently showy, sometimes fragrant, distylous or homostylous; sepals 5, nearly distinct or united into a 10-veined tube, the lobes quincuncial; corolla commonly yellow, sometimes red, orange, pink, or white, frequently with purple spot or dark convergent lines at base of each petal blade, 5 petals distinct, alternate with sepals, with contorted aestivation, sometimes ligulate, clawed, claw adnate to calyx thus forming floral tube; very rarely with corona, narrow, fringed, inserted at the throat, on bases of petal blades and sepal lobes; androecium with 5 stamens, these alternate with petals, filaments inserted at base of floral tube (then flowers hypogynous), or each filament with basal nectary and margins adnate to floral tube up to throat, forming 5 nectariferous pockets (then flowers perigynous), anthers dehiscing by longitudinal slits, commonly dorsifixed, sometimes nearly basifixed; pollen tricolporate, reticulate, binucleate; gynoecium syncarpous, ovary generally superior, or slightly half-inferior, carpels 3, locule 1, styles 3, distinct, erect or reflexed, glabrous or pilose, stigmas generally brush-like; placentation parietal, ovules 1-numerous per placenta, anatropous, bitegmic, crassinucellate. Fruits loculicidal capsules, the surface smooth, verrucous or tuberculate, 3 valves with a median placenta. Seeds 1-60, curved or straight, sometimes ridged, commonly reticulate, the areoles concave or with 1-2 punctiform pits; with a distinct exostome, chalaza rounded, sometimes prominent, navel-like; aril always present, fleshy, membranous when dry, glabrous to exceptionally hairy, generally inserted around hilum.

Notes on delimitation

  • In Cronquist's system (1981) Turneraceae are located in the order Violales, with Achariaceae, Violaceae, Malesherbiaceae, Passifloraceae, and Lacistemataceae.
  • According to the Angiosperm Phylogeny Group (APG II 2003), Turneraceae is placed in the order Malpighiales. Passiflora L., Turnera L. and Malesherbia Ruiz & Pav. form a clade that corresponds to Passifloraceae sensu lato, where an inclusion of Turneraceae and Malesherbiaceae into Passifloraceae was suggested. This clade shows 100% support in Chase et al. (2002); Davis and Chase (2004), as well as in the three-gene study of Soltis et al. (2000), but it is not clear whether there is paraphyly or not among these families.
  • In a recent study of the Malpighiales, by means of plastid DNA sequences, a clade called Violids comprising Achariaceae, Violaceae, Malesherbiaceae, Turneraceae, Passifloraceae, and a Lacistemataceae-Salicaceae (including Flacourtiaceae) lineage was recovered as monophyletic with significant statistical support (Korotkova et al. 2009).
  • In most of the previous studies, Turneraceae and Malesherbiaceae were sister to Passifloraceae, whereas data from Davis and Chase (2004) and Korotkova et al. (2009) provide evidence that Turneraceae and Passifloraceae are sister groups.
  • Among the 40 or so families in the Malpighiales (APG, 2003), only four (Erythroxylaceae, Hypericaceae, Linaceae and Turneraceae) possess distylous species (Shore et al. 2006), and within the clade Violids, Turneraceae is the only one.
  • Interestingly, the families of the Violid clade are the ones assigned by Cronquist (1981) to the order Violales, except for Salicaceae s. str., which was separated in the order Salicales. However, Cronquist drew attention to the fact that Salicales and Flacourtiaceae share many features (many stamens, parietal placentation, separate styles and the presence of salicin in Salix L., Populus L. and Idesia Maxim.) and pointed out that they could be placed nearby.
  • It is noteworthy that all the molecular phylogenies have been made upon one species of each family, so most probably there will be changes when more species are taken into account. 

Distribution in the Neotropics

  • Adenoa Arbo, monotypic, endemic to Cuba.
  • Erblichia Seem., 1 species in Mesoamerica and 4 species in Madagascar.
  • Piriqueta Aubl., 44 species in America and 1 in South Africa.
  • Turnera, 140 species in America and 2 in Africa.

Distinguishing characters (always present)

Other important characters

Key differences from similar families

  • The predominant reproductive system in Turnera and Piriqueta is distyly. About 30% of the species are homostylous, and some species have both distylous and homostylous populations. Distylous species show reciprocal herkogamy, and are usually strongly self-incompatible, while homostylous species are self-compatible. Neither Malesherbiaceae nor Passifloraceae have distylous species.
  • Many species of Turnera and Piriqueta look like Malvaceae or Sterculiaceae: the shape and colour of the flowers are similar, but in the latter families the stamens are not free and the filaments are connate into a tube. Benitez-Vieyra et al. (2007) show that there is floral mimicry between Turnera sidoides Vell. and species of Malvaceae in Argentina.

In Malesherbiaceae and Passifloraceae:

In the flowers of the Malesherbiaceae:

In Passifloraceae:

Number of genera

  • Adenoa
  • Erblichia
  • Piriqueta
  • Turnera

Useful tips for generic identification

Key to Neotropical genera of Turneraceae

1.  Trees 7-30m high, trunk up to 1m wide; showy homostylous flowers 6-8 cm long, with ligulate petals; sepals nearly distinct. Mesoamerica … Erblichia
1.  Herbs, subshrubs, shrubs or treelets up to 4 m high; flowers less than 6 cm long; sepals united into 10-nerved tube … 2

2.  Petals with colleters all along the margin; homostylous flowers; styles divergent at the base … Adenoa (Cuba)
2.  Petals without colleters along the margin; distylous flowers, homostylous in some species; styles converging at the base … 3

3.  Flowers with a membranous laciniate crown, inserted at the floral tube gorge on sepals and petals; peduncle always free; porrect-stellate hairs (central ray longer). Southern USA to Northern Argentina and Uruguay … Piriqueta 3.  Flowers without a crown; peduncle frequently adnate to the petiole (epiphyllous flowers), sometimes free; simple hairs, exceptionally stellate (rays of similar length). Southern USA to 39ºS in Argentina … Turnera

Key to series of genus Turnera

1.  Staminal filaments adnate at the base to the floral tube, rarely free or coherent between them … 2
1.  Staminal filaments adnate along their margins to the petal claws up to the throat, forming nectariferous pockets between each filament and the corresponding sepal … 12

2.  Floral peduncle developed; solitary flowers, sometimes gathered in inflorescences … 3
2.  Floral peduncle not developed or very brief; flowers gathered in terminal or axillary inflorescences, exceptionally axillary and solitary … 10

3.  Floral peduncle totally free or inserted at the petiole base being the remainder free; fruit tuberculate or granulose … 4
3.  Floral peduncle partially or totally adnate to the petiole, at least the apical flowers epiphyllous … 8

4.  Pedicell developed, rarely very brief; solitary flowers, sometimes gathered in axillary cymose inflorescences … Series Salicifoliae
4.  Pedicell absent; flowers solitary or gathered in terminal or axillary racemose inflorecences … 5

5.  Leaves with nectaries at the petiole or at the blade base, on the margin … 6
5.  Leaves without nectaries … 7

6.  Plants without glandular hairs; stipules inserted at both sides of the foliar base; anthers almost basifixed; seed obovoid, rapheal side often straight … Series Stenodictyae
6.  Plants with capitate-sessile or microcapitate glandular hairs; stipules adnate to the foliar base and slightly to the petiole; anthers dorsifixed; seed subglobose, rapheal side convex … Series Annulares

7.  Plants with capitate-sessile or setiform glandular hairs; leaves small (0.4-4.5 cm long.) with stipules well developed … Series Microphyllae
7.  Plants with capitate-stipitate glandular hairs, visible at least at the calyx; leaves small or medium (up to 10cm long.) with stipules reduced or replaced by colleters … Series Papilliferae

8.  Sepals coherent 1/3-1/2 of their length; staminal filaments free; fruit smooth or slightly depressed-reticulate … 9
8.  Sepals united 2/3 of their length; staminal filaments irregularly connate, to different heights; fruit granulose … Series Conciliatae

9.  Flowers generally small, gathered in terminal or lateral capitate racemes; eaves generally medium (2-12 cm long); stipules developed, 0.5-4.5 mm long; fruit slightly depressed-reticulate; seed striate-reticulate; chalaza prominent and concave … Series Capitatae
9.  Flowers medium or small, solitary or gathered in terminal or axillary racemes; leaves small to medium (0.5-12 cm long), frequently with nectaries at apex of petiole or at blade base margin; stipules generally absent or rudimentary, developed in some species (up to 3 mm long); fruit smooth (warty in T. sidoides and T. melochioides var. rugosa); seed reticulate, sometimes the nodes elevated (tuberculate in T. sidoides); chalaza generally rounded, slightly prominent, rarely conical … Series Leiocarpae

10.  Leaves medium to large (4-34 cm long), petiolate, not revolute; stipules well developed, foliar nectaries present or absent … 11
10.  Leaves very small (up to 16 mm long), sessile, entire, revolute; stipules absent, foliar nectaries absent … Series Sessilifoliae

11.  Fruit tuberculate or warty; seed puberulous … Series Salicifoliae
11.  Fruit slightly depressed-reticulate or smooth; seed generally glabrous... Series Capitatae

12.  Floral peduncle free or absent; leaves with or without nectaries … Series Anomalae
12.  Floral peduncle adnate to the petiole, sometimes the apical portion free; leaves with nectaries at the petiole-blade linkage, with a secretory device that looks like a pore … Series Turnera


  • Hairs simple and unicellular in Erblichia and most Turnera, stellate in Adenoa, porrect-stellate in Piriqueta.
  • Glandular hairs long and micro-capitate with swollen bases in Piriqueta, stipitate-capitate in Turnera series Papilliferae, sessile-capitate in most Turnera series Annulares and Microphyllae, micro-capitate in many Turnera (series Anomalae, Capitatae, Leiocarpae and Turnera).
  • Serial axillary buds frequent in Turnera and Piriqueta.
  • Serial branches often developed in Turnera.
  • Stipules developed in Erblichia, and some species of Turnera (series Annulares, Anomalae, Capitatae, Leiocarpae, Microphyllae and Salicifoliae).
  • Foliar nectaries present in Erblichia, a few species of Piriqueta and many species of Turnera, those of series Turnera with a secretory device that looks like a pore.
  • Cymose or racemose inflorescences in some species of Piriqueta and Turnera (series Salicifoliae, Capitatae, Leiocarpae and Anomalae).
  • Prophylls (bracteoles) rudimentary or absent in species of Piriqueta with solitary flowers.
  • Epiphyllous flowers in Turnera (series Conciliatae, Leiocarpae, Turnera and some species of series Anomalae and Capitatae).
  • Distyly in a number of species of Turnera and Piriqueta.
  • Sepals nearly distinct in Erblichia, joint into 10-veined tube with petal claws adhering in Adenoa, Piriqueta and Turnera.
  • Stamens adnate to the floral tube only at the base in Adenoa, Piriqueta and Turnera (series Annulares, Capitatae, Conciliatae, Leiocarpae, Microphyllae, Papilliferae, Salicifoliae, Sessilifoliae and Stenodictyae).
  • Stamen filaments united to petal claws along the margins up to the throat, forming nectariferous pockets, thus floral tube formed by the adnation of calyx, corolla and androecium, in Turnera (series Anomalae and Turnera).
  • Anthers nearly basifixed in Erblichia and Turnera (series Stenodictyae and Turnera).
  • Ovary slightly half-inferior in Turnera (series Turnera and Anomalae),
  • Fruit usually naked, dressed with the remnants of the floral pieces in Adenoa and a few species of Turnera.
  • Seed somewhat to considerably curved, straight in Turnera series Annulares and a few species of series Leiocarpae; chalaza usually rounded, prominent and navel-like in Turnera series Anomalae, Capitatae, Conciliatae, Salicifoliae, Stenodictyae and Turnera subseries Umbilicatae.
  • Seed coat slightly striate in Adenoa and Erblichia; reticulate in Piriqueta, areoles concave, often with 1 or 2 punctiform pits; usually reticulate, areoles concave sometimes with 1 punctiform pit, occasionally ridged or tuberculate in Turnera.

Notable genera and distinguishing features

  • Adenoa - shrub with stellate hairs, coriaceous tomentose leaves, without extrafloral nectaries. Flowers homostylous, solitary, peduncle developed, floral tube with nectariferous inner face, petals with colleters along the margin; corona absent; free staminal filaments, anthers dorsifixed; exerted stigmas. Capsule tomentose, dehiscent down to the middle, dressed at maturity with the remnant parts of the flowerSeed obovoid, striate, chalaza rounded not prominent, aril narrow.
  • Erblichia - tree with simple hairs, large leaves with small marginal nectaries. Flowers large, showy, fragrant, homostylous, solitary; peduncle and pedicel developed; sepals almost distinct; petals ligulate; stamens free, anthers dorsifixed; exerted stigmas. Capsule ellipsoidal, granulose. Seed obovoid, striate, chalaza rounded, not prominent; aril wide, oily, yellow or reddish, membranous when dry.
  • Piriqueta - herbs, subshrubs or shrubs with porrect-stellate hairs, long glandular hairs with swollen base in most species. Leaves rarely with nectaries. Flowers usually distylous, sometimes homostylous, solitary, sometimes gathered in cymose inflorescences, hardly ever in an apical raceme; peduncle and pedicel developed, bracteoles generally wanting; floral tube with a membranous crown at the throat; stamens adnate only at the base to the floral tube; anthers generally dorsifixed; styles sometimes bifurcate, stigmas generally brush-like. Capsule granulose, in a few species smooth. Seeds obovoid, reticulate, areoles slightly concave, in many species with a punctiform cavity, in a few species with 2 punctiform cavities; chalaza generally rounded, not prominent; aril narrow or wide.
  • Turnera - herbs, subshrubs, shrubs or treelets with simple hairs, stellate in a few species, glandular hairs sessile-capitate, stipitate-capitate or microcapitate. Leaves often with nectaries. Flowers usually distylous, sometimes homostylous, solitary or gathered in cymose or racemose inflorescences; peduncle absent or developed, often adnate to the petiole, then flowers epiphyllous; pedicel generally not developed; bracteoles 2, persistent; floral tube formed by calyx and corolla, or by calyx, corolla and androecium; petals ligulate in a few species; anthers dorsifixed, sometimes almost basifixed; stigmas generally brush-like. Capsule granulose or smooth. Seeds obovoid, in a few species almost globose, chalaza rounded or prominent, sometimes concave; seed coat sometimes striate, usually reticulate, areoles sometimes with a punctiform cavity; aril narrow or wide, hardly ever pilose.


  • All genera are native, some species are cultivated (Erblichia odorata Seem. (flor de fuego, butterfly tree), Turnera subulata Sm. (buttercup, chanana, guarujá), Turnera ulmifolia L. (cat bush, ram-goat dash-along, sundrops, yellow alder).
  • Some species are weedy, e.g. Turnera subulata in the North of Brazil and Turnera ulmifolia in the Caribbean Islands. 
  • There is a very high rate of endemism in the family; Adenoa cubensis (Britton & Wilson) Arbo is endemic to Cuba, and there are many endemic and rare species within Turnera and Piriqueta.

General notes

  • The chromosome number is known in some species of Piriqueta and Turnera.  In Piriqueta the basic number is x=7, while in Turnera there are 3 basic numbers: x=7, x=13 and x=5.

Important literature

APG. 2003. An update of the angiosperm phylogeny group classification for the orders and families of flowering plants: APG II. Bot. J. Linn. Soc. 141: 339-436

Arbo M.M. 1977. Adenoa, nuevo genero americano de Turneraceae. Hickenia 1(16): 87-91

Arbo M.M. 1979. Revisión del género Erblichia (Turneraceae). Adansonia, ser. 2, 18(4): 459-482.

Arbo M.M. 1995. Turneraceae Parte I. Piriqueta. Flora Neotropica (Monograph 67, 156 pages, 59 figs.

Arbo, M.M. 1997. Estudios sistemáticos en Turnera (Turneraceae). I. Series Salicifoliae y Stenodictyae. Bonplandia (Argentina) 9(3-4): 151-208

Arbo M.M. 2000. Estudios sistemáticos en Turnera (Turneraceae). II. Series Annulares, Capitatae, Microphyllae y Papilliferae. Bonplandia (Argentina) 10: 1-82.

Arbo M.M. 2004. Turneraceae in Smith N. et al. (eds.) "Flowering Plants of the Neotropics". Princeton University Press.

Arbo M.M. 2005. Estudios sistemáticos en Turnera (Turneraceae). III. Series Anomalae y Turnera. Bonplandia (Argentina) 14(3-4): 115-318.

Arbo M.M. 2007. Turneraceae in Kubitzki K., The families and genera of vascular plants, Springer. Alemania. Vol. IX: 458-466.

Arbo M.M. 2008. Estudios sistemáticos en Turnera (Turneraceae). IV. Series Leiocarpae, Sessilifoliae y Conciliatae. Bonplandia (Argentina) 17(3-4): 107-334.

Benitez-Vieyra S., Hempel de Ibarra N., Wertlen A.M. & Cocucci A.A.  2007. How to look like a mallow: evidence of floral mimicry between and Malvaceae. Proc. R. Soc. B. 274: 2239-2248.

Chase M.W., Zmartzy S., Lledó M.D., Wurdack K.J., Swensen S.M. & Fay M.F. 2002. When in doubt, put it in Flacourtiaceae: a molecular analysis based on plastid rbcL sequences. Kew Bull.57: 141-181.

Cronquist A. 1981. An integrated system of classification of flowering plants. Columbia University Press, New York.

Davis C.C. & Chase M.W. 2004. Elatinaceae are sister to Malpighiaceae; Peridiscaceae belong to Saxifragales. Amer. J. Bot. 91: 262-273.

Korotkova N., Schneider J.V., Quandt D., Worberg A., Zizka G. & Borsch T. 2009. Phylogeny of the eudicot order Malpighiales: analysis of a recalcitrant clade with sequences of the petD group II intron. Pl. Syst. Evol. 271, on line.

Shore J.S., Arbo M.M. & Fernández A. Breeding system variation, genetics and evolution in the Turneraceae. New Phytologist 171: 539-551.

Soltis D.E., Soltis P.S., Chase M.W., Mort M.E., Albach D.C., Zanis M., Savolainen V., Hahn W.H., Hoot S.B., Fay M.F., Axtell M., Swensen S.M., Prince L.M., Kress W.J., Nixon K.C., Farris J.S. 2000. Angiosperm phylogeny inferred from 18S rDNA, rbcL, and atpB sequences. Bot. J. Linn. Soc. 133: 381-461.

Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 [and more or less continuously updated since].

How to cite

Arbo, M.M. (2009). Neotropical Turneraceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.

Click images to enlarge

Flowering branch of Adenoa cubensis showing extrorse styles © Fernando Zuloaga, Darwinion Institute (SI).

Adenoa cubensis. A, part of the calyx, internal face, petals with colleters along the margin and stamen. B, colleter longisection. C, colleter transection. D, pistil © Instituto de Botánica del Nordeste (CTES).

Flowering plant, Piriqueta morongii © Heather Machado.

Hairs of Piriqueta spp. A, P. viscosa ssp. viscosa, porrect-stellate. B, P. densiflora var. goiasensis, porrect-stellate. C, P. morongii , setiform glandular and porrect-stellate. D, P. sulfurea , porrect-stellate © A, B, D: M.M. Arbo; C: A.M. Gonzalez.

Piriqueta spp. seeds. A, P. caiapoensis. B, P. nanuzae. C, P. cistoides subsp. cistoides. D, P. rosea . A, aril. c, chalaza. e, exostome. r, raphe © M.M. Arbo.

Floral morphology variation in Piriqueta sp. and Turnera sp. A, D, G, H, I: leaf-floral axis relations. B, E, J: internal view of calyx, with adherent petal claws and basal portions or staminal filaments; in B, crown inserted on sepals and petals. C, F, K: transection of flower, showing the relationships among the different whorls. a, fruit. b, pedicel. c, peduncle. e, petiole. f, leaf. g, floral nectary. h, calyx tube. i, calyx lobes. j, base of petal blade. k, crown. l, basal portion of staminal filament, the free part was cut. m, nectariferous pocket. n, ovary. o, style. p, floral tube © M.M. Arbo.

Flowering branch of Turnera grandiflora: a, epiphyllous flower. b, bracteole. t, floral tube © M.M. Arbo.

Turnera orientalis: a, anther. b, style. c, stigma © M.M. Arbo.

Seeds of Turnera piriqueta: a, aril. c, chalaza © M.M. Arbo.

Turnera sp., variation in staminal filaments coherence © Instituto de Botánica del Nordeste (CTES).

Buds and leaves of Turnera sp. © Instituto de Botánica del Nordeste (CTES).

Turnera sp., fruits with persistent bracteoles © Instituto de Botánica del Nordeste (CTES).

Habit, herb and shrub of Turnera sp. © M.M. Arbo.

Tector and glandular hairs of Turnera sp. © A-E,H-I: M.M.Arbo F-G: A.M. Gonzalez.

Ovules and seed of Turnera sp. © M.M. Arbo.

Seeds of Piriqueta spp.: A, P. caiapoensis. B, P. nanuzae. C, P. cistoides subsp. cistoides. D, P. rosea . A, aril. c, chalaza. e, exostome. r, raphe © M.M. Arbo.

Axillary buds of Turnera sp. © Instituto de Botánica del Nordeste (CTES).