Neotropical Connaraceae

Enrique Forero

Universidad Nacional de Colombia, Bogotá, Colombia. 

Description

Small trees, shrubs or lianas. Stipules absent. Leaves alternate, compound, imparipinnate, leaflets usually alternate on the rachis, margin entire or rarely revolute; blades sometimes with papillae present on abaxial surface (Pseudoconnarus Radlk., and some Rourea Aubl.); hairs unicellular (most species), dendroid (many Connarus L.), or sometimes glandular (Connarus). Inflorescences axillary, pseudoterminal or terminal, paniculate, racemose, or spicate. Flowers actinomorphic, bisexual, usually < 1 cm long, dark punctuations sometimes present (most Connarus) on petals, sepals, stamens and styles; sepals 5, distinct or partially fused, imbricate or valvate, often pubescent, persistent in fruit; petals 5 distinct, sometimes appearing fused just above the base, white, light yellow, or light pink, usually glabrous, sometimes pubescent (Connarus), the hairs sometimes glandular; androecium of 10 stamens, 5 long, episepalous, 5 short, epipetalous, the filaments glabrous, sometimes forming a tube at the base, sometimes glandular hairs present (Connarus), the anthers dorsifixed, glandular hairs sometimes present at top of connective (Connarus); gynoecium apocarpous, the ovaries superior, glabrous or pubescent, the carpels 1 (Connarus) or 5 (remaining genera), the styles 1 per carpel, the stigmas capitate or 2-lobed; ovules 2 per carpel but one aborting, nearly basal, collateral, orthotropous. Fruits follicles, 1 (Cnestidium Planch., Connarus, Rourea) to several (Bernardinia Planch., Pseudoconnarus), often red at maturity, the persistent sepals covering the base, usually ascending or reflexed (Bernardinia and some Rourea). Seeds 1, black; aril bright red, yellow, white, or orange; endosperm abundant (Pseudoconnarus), poorly developed (Cnestidium) or absent.

Notes on delimitation

  • The delimitation of the family has not been questioned.

Distribution in the Neotropics

  • Bernardinia: monotypic, Pará to São Paulo, Brazil (endemic to tropical America).
  • Cnestidium: two species, from México through Central America to Colombia, Venezuela, the Guianas, Ecuador and Cuba (endemic to tropical America).
  • Connarus: 54 species, from Mexico to Southern Brazil (pantropical).
  • Pseudoconnarus: five species, Colombia, Venezuela, Guyana, Suriname, Peru, and the states of Acre, Amazonas and Pará in Brazil (endemic to tropical America).
  • Rourea: 48 species, from Mexico to Southern Brazil (pantropical).

Distinguishing characters (always present)

Other important characters

  • Dendroid and glandular hairs (several species of Connarus).
  • Glandular punctuations on flower parts (most Connarus).
  • Papillae on lower surface of leaflets (Pseudoconnarus, some species of Rourea).
  • Two or more carpels maturing in Bernardinia and Pseudoconnarus, sometimes in Cnestidium, very rarely in Rourea.

Key differences from similar families

  • The lack of stipules is a key difference from the Leguminosae in sterile herbarium material.

Number of genera

Five genera:

  • Bernardinia
  • Cnestidium
  • Connarus
  • Pseudoconnarus
  • Rourea

Useful tips for generic identification

Keys to genera of Neotropical Connaraceae

Key based mainly on flowering material

1. Carpel solitary at flowering stage; petals with glandular punctuations … Connarus
1. Carpels 5 at flowering stage; petals without glandular punctuations ... 2

2. Sepals valvate or only narrowly imbricate; inflorescence (and fruit) densely pilose... Cnestidium
2. Sepals imbricate; inflorescence (and fruit) usually glabrous or villous but not densely pilose... 3

3. Ovary slightly stipitate; leaves consistently trifoliolate; leaflets papillose below... Pseudoconnarus
3. Ovary sessile; leaves uni-, tri- or multifoliolate; leaflets usually without papillae (when papillae present,   then leaflets more than five, i.e., Rourea spp.) ... 4

4. Flowers produced before or approximately at the same time as the leaves; fruiting calyx reflexed and more or less caduceus … Bernardinia
4. Flowers produced after the leaves; fruiting calyx ascending, often accrescent, rarely reflexedRourea

Key based mainly on fruiting material

1. Follicle usually solitary at maturity ... 2
1. Follicles several at maturity ... 4

2. Fruiting calyx usually accrescentRourea
2. Fruiting calyx not accrescent... 3

3. Endosperm absent; sepals imbricateConnarus
3. Endosperm present but scanty; sepals valvate or only narrowly imbricateCnestidium

4. Endosperm copious; leaves trifoliolate, the leaflets papillose below; flowers produced after the leaves …Pseudoconnarus
4. Endosperm absent; leaves imparipinnate, the leaflets lacking papillae below; flowers produced before or approximately at the same time as the leaves ... Bernardinia

Notable genera and distinguishing features

  • Connarus can be distinguished from the other four American genera by the presence of one carpel only. This is the richest genus in terms of number of species in the Neotropics (54).
  • Rourea is represented by 48 species. The areas of distribution of Rourea and Connarus overlap.
  • Both Rourea (Rourea induta Planch.) and Connarus (Connarus suberosus Planch.) are important components of the Cerrado vegetation of central Brazil.
  • Bernardinia stands out as being a monotypic genus that grows only in the eastern part of Brazil (states of Bahia, Minas Gerais, Rio de Janeiro, extending north to Pará and south to São Paulo).
  • Pseudoconnarus can be easily distinguished by the trifoliolate leaves, always with papillae on the lower surface of the leaflets. Its distribution is restricted to northern South America.
  • Cnestidium includes two species that are mutually exclusive geographically: C. guianensis grows in the Guianas and eastern Venezuela, while C. rufescens Planch. is known from Mexico to Colombia, western Venezuela, Ecuador and Cuba.

Status

  • All five genera are native.
  • Three out of the five native genera are endemic to the Neotropics. Their geographic distribution within the region is given above under "Distribution in the Neotropics".

General notes

  • The Connaraceae were placed in the Rosales by Cronquist (1981) and in the Connarales by Takhtajan (1987).
  • The APG (2003) placed the family in the Oxalidales, next to the Oxalidaceae, Brunelliaceae, Cephalotaceae, Cunoniaceae, and Elaeocarpaceae.
  • The family is pantropical and includes 16 genera and about 300-350 species.
  • Its center of distribution is Western Africa.
  • In the Neotropics there are 5 genera and 110 species.
  • While most species are found mostly within the tropics of Cancer and Capricorn, two taxa extend past 27° S in the state of Santa Catarina, Brazil: Connarus rostratus (Vell.) L.B.Sm. and Rourea gracilis G.Schellenb.

Important literature

Angiosperm Phylogeny Group (A.P.G. II) 2003.  An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APGII.  Botanical Journal of the Linnean Society.

Cronquist, A. 1981. An Integrated System of Classification of Flowering Plants. Columbia University Press, New York.

Forero, E. 1976. A Revision of the American species of Rourea subgenus Rourea (Connaraceae). Mem. New York Bot. Gard. 26 (1): 1-119.

Forero, E., E. Carbonó, C.I. Orozco, E. Ortega, J.E. Ramos R. Ruiz, O. S. de Benavides & L.A. Vidal 1983. Connaraceae. Fl. Colombia 2: 1-83.

Forero, E 2002. Connaraceae. In S.A. Mori, G. Cremers, C. Gracie, J.-J. de Granville, S.V. Heald, M. Hoff & J.D. Mitchell (eds.), Guide to the Vascular Plants of Central French Guiana. Part 2. Dicotyledons. Mem. New York Bot. Gard. 76 (2): 227-230, pl. 45a-c.

Forero, E. 1983. Connaraceae. Fl. Neotropica Monograph 36: 1-207.

Forero, E. 2004. Connaraceae. In Flowering Plants of the Neotropics, N. Smith, S.A. Mori, A. Henderson, D. Wm. Stevenson and S.V. Heald (eds.), 112-113. The New York Botanical Garden, Bronx, New York, U.S.A. and Princeton University Press, Princeton, New Jersey, U.S.A.

Forero, E. & L.H.Y. Kamino 2008. Connaraceae. In Stehmann, J.R., R.C. Forzza & L.H.Y. Kamino (eds.), Lista das especies de plantas da Mata Atlântica. Belo Horizonte. http://www.icb.ufmg.br/bot/mataatlantica/basededados.php

Schellenberg, G. 1938. Connaraceae. In Das Pflanzenreich, A. Engler (ed.), Series 4, 127 (Heft 103): 1-326. Leipzig: Wilhelm Engelmann.

Takhtajan, A. 1987.  Systema Magnoliophytorum.  Academia Scientiarum URSS.  Institutum Botanicum Nomine V. L. Komarov.  Leninopoli, Officina Editoria "Nauka", Sectio Leninopolitana. p. 166, 168-169. (in Russian).

How to cite

Forero, E. (2009). Neotropical Connaraceae. 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/Connaraceae.htm.