Eve Lucas & Laura Jennings
Royal Botanic Gardens, Kew, UK.
Trees or woody shrubs; hairs simple or occasionally dibrachiate. Leaves opposite or sometimes sub-opposite. Inflorescences very variable, can be terminal or usually axillary, solitary, dichasial, racemose, glomerulous or sometimes paniculate; perianth free in 4 to 5 parts or calyx calyptrate; stamens free, numerous; anthers versatile, dehiscing by longitudinal slits. Ovary generally inferior, occasionally semi-inferior, mostly 2, 3 or 4 (-10) locular; placentas axile, ovules radiating, sometimes pendulous; vascular supply to ovary trans-septal. Fruit indehiscent, fleshy; seeds usually numerous; embryo variable with cotyledons small and straight or elongate and curved, well developed and leafy or homogenous.
Distribution in the Neotropics
- Acca O. Berg: Brazil to Peru and Uruguay.
- Accara Landrum: Brazil.
- Amomyrtella Kausel: Bolivia and Northern Argentina.
- Amomyrtus (Burret) Legrand & Kausel: Chile, just into W. Argentina.
- Blepharocalyx O. Berg: Brazil, Bolivia and Paraguay, Chile and Argentina.
- Calycolpus O. Berg: Panama and Colombia, Venezuela to Peru and Trinidad, Guyana and Northern Brazil.
- Calycorectes O. Berg: Cuba, Mexico south to Northern Argentina.
- Calyptranthes Sw.: Florida and Caribbean, Mexico south to Northern Argentina.
- Campomanesia Ruíz & Pavón: Brazil north to Venezuela and Trinidad, west to Colombia and Peru and south to Northern Argentina.
- Chamguava Landrum: Mexico (Guerrero, Chiapas) to Honduras and Panama.
- Eugenia L. Pantropical - in the Neotropics: Southern Florida and Caribbean and from Mexico to Argentina.
- Gomidesia O. Berg: Brazil north to Venezuela, Guyana and the Caribbean to Hispaniola, south into Paraguay and Argentina.
- Hexachlamys O. Berg: Southern Brazil and Paraguay to Bolivia and Northern Argentina.
- Legrandia Kausel: Chile.
- Luma A. Gray: Peru: Chile and Argentina.
- Marlierea Cambess.: Trinidad-Tobago and Windward Is., Costa Rica to Colombia, Venezuela and the Guianas and Northern Brazil.
- Mosiera Small: Southern Florida and Caribbean.
- Myrceugenia O. Berg: Brazil to Argentina, Chile and Juan Fernandez Is.
- Myrcia DC. ex Guillemin: Mexico and Caribbean south to Argentina.
- Myrcianthes O. Berg: Florida and Caribbean, Mexico south to Chile, Argentina and Uruguay.
- Myrciaria O. Berg: Guatemala and Belize south to Paraguay and Northern Argentina.
- Myrrhinium Schott: Ecuador and Peru to Southern Brazil and Northern Argentina.
- Myrteola O. Berg: From the Andes of Colombia south to Tierra del Fuego and Falkland Is.
- Neomitranthes Legrand: SE. and Southern Brazil.
- Pimenta Lindl.: Caribbean from Cuba to Trinidad, Mexico (Veracruz, Oaxaca) to Panama, Southern Bolivia, Southern and SE. Brazil.
- Plinia L.: Caribbean: Costa Rica south through tropical South America to Argentina.
- Psidium L.: Southern Mexico and Caribbean through tropical South America to Northern Argentina.
- Siphoneugena O. Berg: Brazil north to Venezuela, the Guianas and Caribbean to Puerto Rico, south into Argentina.
- Tepualia Griseb.: Chile.
- Ugni Turcz.: Guatemala to Guyana (Mt. Roraima) and Chile, Juan Fernandez Is.
Distinguishing characters (always present)
- No characters are ALWAYS present.
Other important characters
- Opposite, simple leaves.
- Pellucid gland dots on leaves and often other parts.
- Leaves aromatic when crushed.
- Intramarginal collecting vein present.
- Inferior ovary.
- No evident stipules.
- Many (>100) stamens.
Key differences from similar families
The families listed below differ from Myrtaceae in the following characters:
- Clusiaceae: plants usually with latex; leaves sometimes with dark resin-filled dots; flowers often unisexual; ovary superior.
- Malpighiaceae: leaves without translucent dots, an interpetiolar scar often present; flowers with clawed petals, few stamens; calyx with prominent glands at the base on the outer surface.
- Oleaceae: leaves sometimes serrate; no part of plant bearing pellucid gland dots; stamens 2; ovary superior.
- Melastomataceae (especially Mouriri): plants without translucent dots; no part of plant bearing pellucid gland dots; stamens <20, anthers sickle shaped and isomerous; inflorescences often cymose.
- Rubiaceae (especially in fruit): plants without translucent dots; interpetiolar stipules distinct in most specimens; corolla tubular; stamens 4-5.
- Rutaceae (species with simple leaves): leaves alternate; flowers with few stamens; prominent intrastaminal nectary-disc; ovary superior.
Number of genera
- 29 genera: Acca, Accara, Amomyrtella, Amomyrtus, Blepharocalyx, Calycolpus, Calycorectes, Calyptranthes, Campomanesia, Chamguava, Eugenia, Hexachlamys, Legrandia, Luma, Marlierea, Mosiera, Myrceugenia, Myrcia, Myrcianthes, Myrciaria, Myrrhinium, Myrteola, Neomitranthes, Pimenta, Plinia, Psidium, Siphoneugena, Tepualia, Ugni.
Useful tips for generic identification
- Observe texture of seed testa.
- Observe embryo shape and size.
- Observe number of perianth parts.
- Observe inflorescence architecture.
- Note collection locality.
Notable genera and distinguishing features
- Blepharocalyx: seed testa soft, embryo c-shaped, perianth 4-merous, parts free, arranged in a distinctive square upon ovary; inflorescences in complex branching dichasia of up to 35 flowers; single very variable and widely distributed species in Brazil, Venezuela and tropical Argentina.
- Eugenia: seed testa soft; embryo homogenous resembling a bean; perianth mostly 4-merous, parts free, flowers often subtended by evident, conspicuous bracts; inflorescences solitary, in fascicles, spikes or racemes; widely distributed throughout the Neotropics, > 1,000 species.
- Myrcia s.l.: seed testa soft; embryo membranous, plicate with long, distinct hypocotyl; perianth mostly 5-merous, calyx lobes free or fused, tearing open irregularly or circumscissile and falling as a calyptra; inflorescences in panicles; widely distributed throughout the Neotropics, > 700 species.
- Myrceugenia: seed testa soft; embryo membranous, plicate with long, distinct hypocotyl; perianth mostly 4-merous, parts free (rarely circumscissile), valvate; inflorescences solitary or in dichasia; common in Brazil to Argentina: Chile and the Juan Fernandez Islands.
- Pimenta: seed testa hard in all but one species, embryo c-shaped, perianth (4-)5-merous, parts free; inflorescences in complex branching dichasia of many flowers; extremely aromatic plant; common in central America, the Caribbean and southern Brazil.
- Psidium: seed testa hard, embryo c-shaped, perianth mostly 4-merous, parts free to fused often tearing open irregualarly; inflorescences solitary or in panicles; common throughout South America.
- Myrciaria, Neomitranthes, Plinia and Siphoneugena: seed testa soft; embryo homogenous resembling a bean; perianth mostly 4-merous, parts free or fused and falling as a circumscissile but open ring or tearing irregularly; inflorescences mostly sessile and in glomerules; central America, the Caribbean and particularly common in southern Brazil.
- All genera listed are native, and all but Eugenia are endemic to the Neotropics.
- Psidium (Guava), Eugenia uniflora (Pitanga) and Myrciaria cauliflora (Jaboticaba) are widely cultivated for fruit, jams and juices.
- Syzygium jambos and various Eucalyptus species are introduced, cultivated (for fruit and timber/shade respectively) and are often naturalized.
Govaerts, R., Sobral, M., Ashton, P., Barrie, F., Holst, B.K., Landrum, L.L., Matsumoto, K., Mazine, F.F., Nic Lughadha, E., Proença, C., Soares-Silva, L.H., Wilson, P.G. and Lucas, E. 2008. World Checklist of Myrtaceae. Kew Publishing: Royal Botanic Gardens, Kew.
Landrum, L.R. and Kawasaki, M.L. 1997. The genera of Myrtaceae in Brazil: an illustrated synoptic treatment and identification keys. Brittonia. 49: 508-536.
Lucas, E.J., Harris, S.A., Mazine, F.F., Belsham, S.R., Nic Lughadha, E.M., Telford, A., Gasson, P.E. and Chase, M.W. 2007. Suprageneric phylogenetics of Myrteae, the generically richest tribe in Myrtaceae (Myrtales). Taxon 56: 1105-1128.
McVaugh, R. 1956. Tropical American Myrtaceae, notes on generic concepts and descriptions of previously unrecognized species. Fieldiana, Bot. 29: 145-228.
McVaugh, R. 1963. Tropical American Myrtaceae, II, notes on generic concepts and descriptions of previously unrecognized species. Fieldiana 29: 393-532.
McVaugh, R. 1968. The genera of American Myrtaceae - an interim report. Taxon 17: 354-418.
How to cite
Lucas, E. & Jennings, L. (2009). Neotropical Myrtaceae. 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/Myrtaceae.htm.
Click images to enlarge
Many stamens of Acca sellowiana © F. Forest, RBG, Kew.
Blepharocalyx sp. © W. Milliken, RBG, Kew.
Calyptranthes sp. © W. Milliken, RBG, Kew.
Eugenia florida © D. Sasaki, RBG, Kew.
Eugenia punicifolia © W. Milliken, RBG, Kew.
Four perianth parts; solitary inflorescence of Eugenia sp. © L. Jennings, RBG, Kew.
Plicate embryo of Myrcia s.l. and Myrceugenia © L. Jennings, RBG, Kew.
Myrciaria dubia © D. Sasaki, RBG, Kew.
Myrcia splendens with paniculate inflorescences © L. Jennings, RBG, Kew.
Myrcia splendens © D. Sasaki, RBG, Kew.
Leaf showing pellucid gland dots of Myrcia reticulosa © E. Lucas, RBG, Kew.
Leaf showing intramarginal vein of Myrcia reticulosa © E. Lucas, RBG, Kew.
Myrcia sp. © W. Milliken, RBG, Kew.
Myrceugenia sp. with valvate calyx lobes © E. Lucas, RBG, Kew.
Fleshy, sessile fruits of Plinia sp.© L. Jennings, RBG, Kew.
Psidium guieense © D. Zappi, RBG, Kew.