Neotropical Cunoniaceae

Helen C.F. Hopkins

Royal Botanic Gardens, Kew, U.K. 

Description

Trees or shrubs, or rarely hemi-epiphytes. Indumentum of simple hairs. Leaves opposite and decussate, simple or compound (imparipinnate, trifoliolate or palmately compound); blade margins toothed, crenate or rarely entire; in compound leaves, petiole and/or rachis winged or not; venation semi-craspedodromous (or craspedodromous in Caldcluvia, extra-tropical). Stipules interpetiolar (2 per node) or free-lateral (4 per node). Inflorescences racemose or paniculate/thyrsoid (or flowers solitary, Eucryphia, extra-tropical). Flowers hermaphrodite; perianth of 1 or 2 whorls, polysymmetric; sepals 4-6 (-7), valvate or imbricate in bud; petals absent or 4 (-5 in Caldcluvia), alternating with sepals, free, small, thin (or large and showy, Eucryphia); disc annular, or lobed, or adnate to ovary and inconspicuous; stamens twice as many as sepals or 8; filaments slender, anthers subrotund, longitudinally dehiscent down 2 sutures; gynoecium superior; carpels 2 (-12, Eucryphia), syncarpous at level of ovary; stylodia as many as carpels, free; ovules 8, in 2 rows on axile placentas. Fruits dehiscent, dry; seeds small, winged or hairy.

Notes on delimitation

  • Molecular studies have resolved questions of family delimitation, e.g. Eucryphia is now placed within Cunoniaceae (previously often segregated in its own family) (see Bradford & Barnes 2001).
  • Although historically Cunoniaceae was considered close to Saxifragaceae, it belongs to Oxalidales (APG II), where among neotropical families it is close to Brunelliaceae, Connaraceae, Elaeocarpaceae and Oxalidaceae.

Distribution in the Neotropics

Worldwide the family comprises some 27 genera and 300-350 species. Two genera occur in the Neotropics (Lamanonia, Weinmannia) and together contain ~90 species in the Americas (i.e. including a few extra-tropical ones):

  • Lamanonia (syn. Belangera): (endemic, 5 spp.) Central, E and S Brazil, Paraguay, N Argentina; forest.
  • Weinmannia: (native, 85+ spp.) Andes (S Mexico to Chile and NW Argentina), Caribbean Islands, Venezuela, Guianas and E Brazil with the greatest concentration of species in Colombia, Ecuador and Peru; mostly in forest, especially montane tropical forest and subtropical forest, extending into temperate forest in the south; absent from the lowlands of the Amazon basin.

Two further genera occur in temperate South America:

  • Caldcluvia: (endemic, 1 spp.) central Chile (and Argentina?); forest.
  • Eucryphia: (native, 2 spp.) Chile; forest.

Distinguishing characters (always present)

  • Leaves opposite; stipules present.
  • Flowers dish-shaped; perianth polysymmetric, pale (white, pale pink, yellowish).
  • Gynoecium superior; carpels united at level of ovary, surmounted by free stylodia.
  • Fruits capsular; seeds numerous.

Other important characters

  • Margins of blades usually toothed.

Key differences from similar families

  • Weinmannia resembles Brunellia (Brunelliaceae) and Staphylea (formerly Turpinia p.p., Staphyleaceae) in having opposite, usually toothed leaves (simple or pinnate in Brunellia, imparipinnate in Staphylea) and stipules (interpetiolar in Brunellia, free-lateral in Staphylea), and all three genera occur in montane neotropical forest.

Weinmannia can be distinguished as follows:

  • It has a syncarpous ovary (2 carpels) with free stylodia (vs carpels free, 4-6 [-8] in Brunellia; carpels 2-3, partially free or united at level of ovary, stylodia fused distally in Staphylea);
  • Axillary racemes (vs axillary panicles/thyrses in Brunellia; axillary or terminal panicles in Staphylea);
     stipels absent at base of leaflets in compound leaves (vs stipels present in Brunellia; small glands present in Staphylea);
  • Petals caducous, often falling like a cap (vs absent in Brunellia; present and not caducous in Staphylea);
  • Seeds hairy (vs arillate in Brunellia; without aril or hairs in Staphylea).

Lamanonia is unlikely to be confused with Brunelliaceae or Staphyleaceae.

Number of genera

  • see above under Distribution.

Useful tips for generic identification

Key to genera of Neotropical Cunoniaceae (including extra-tropical genera):

1. Flowers small (< 1 cm diameter) with or without petals, several to many per inflorescence … 2
1. Flowers large (3-5 cm diameter) with showy petals, solitary … Eucryphia

2. Inflorescence paniculate/thyrsoid; stipules free-lateral (4 per node); venation craspedodromousCaldcluvia
2. Inflorescence of axillary racemes (panicle in one species of Weinmannia from Colombia); stipules various; venation semi-craspedodromous … 3

3. Leaves palmately compound (leaflets usually 3 or 5); stipules free-lateral (4 per node); corolla absent; stamens 8 (> 2x number of calyx lobes) … Lamanonia
3. Leaves simple or imparipinnately compound (including 3-foliolate); stipules interpetiolar (2 per node); corolla present but caducous; stamens 2x number of calyx lobes … Weinmannia

Notable genera and distinguishing features

  • Weinmannia - Often a significant component of cloud forests in the Andes where several species can co-occur at one locality or in a single altitudinal zone. Species-level identification often depends on vegetative characters and can be problematic; interspecific hybridization is probably common (Harling 1999).

Status

  • See above under Distribution.

General notes

  • Cunoniaceae is a largely southern hemisphere family with its centre of generic diversity in the SW Pacific and E Australia. Few genera and a limited range of morphological characters are seen in the Neotropics.
  • Weinmannia is the only widely distributed genus. Besides the Americas, it is also found in the Indian Ocean [Madagascar, Comores, Mauritius, Reunion], and in Malesia, the W and Central Pacific and New Zealand. All species in the Americas belong to sect. Weinmannia, which also contains 2 species from the Mascarene Islands (Bradford 1998, 2002).
  • The remaining genera in Latin America have strong amphi-Pacific relationships. Lamanonia and Caldcluvia both have their closest relatives in the SW Pacific and E Australia, and the remaining species of Eucryphia occur in E Australia (including Tasmania).
  • Species in several genera, including Weinmannia and Eucryphia, are sources of nectar for honey.

Important literature

Bausch, J. 1938. A revision of the Eucryphiaceae. Bull. Misc. Inform. Roy. Bot. Gard. Kew 1938: 317-349.

Bradford J.C. 1998. A cladistic analysis of species groups in Weinmannia (Cunoniaceae) based on morphology and inflorescence architecture. Ann. Missouri Bot. Gard. 85: 565-593.

Bradford, J.C. 2002. Molecular phylogenetics and morphological evolution in Cunonieae (Cunoniaceae). Ann. Missouri Bot. Gard. 89: 491-503.

Bradford, J.C. & Barnes, R.W. 2001. Phylogenetics and classification of Cunoniaceae (Oxalidales) using chloroplast DNA sequences and morphology. Syst. Bot. 26: 354-385.

Bradford, J.C., Hopkins, H.C.F. & Barnes, R.W. 2004. Cunoniaceae. In: K. Kubitzki (ed.), The Families and Genera of Vascular Plants 6: 91-111. Springer, Berlin.

Harling, G. 1999. 78. Cunoniaceae, in G. Harling & L. Andersson (eds), Flora of Ecuador no. 61. Council of Nordic Publications in Botany, Copenhagen.

Kubitzki, K. 2004. Brunelliaceae. In: K. Kubitzki (ed.), The Families and Genera of Vascular Plants 6: 26-28. Springer, Berlin.

Simmons, S.I. 2006. Staphyleaceae. In K. Kubitzki (ed.), The Families and Genera of Vascular Plants 9: 91-111. Springer, Berlin.

Zickel, C. S. & Leitão Filho, H. de F. 1993. Revisão taxonômica de Lamanonia Vell. (Cunoniaceae). Revista Brasil. Bot. 16: 73-91.

How to cite

Hopkins, H.C.F. (2009). Neotropical Cunoniaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Cunoniaceae.htm.