Neotropical Myristicaceae

Denise Sasaki

Secretaria do Meio Ambiente do Estado de São Paulo, Brazil. 

Description

Trees, sometimes shrubs, usually evergreen; bark often vertically ridged or peeling in thick plates; branches usually whorled and horizontally spreading. Exudate present, initially watery, red or pinkish or straw-coloured (Osteophloeum). Leaves simple, alternate, often distichous, regularly spaced 2-ranked, entire, pinnately veined, sometimes gland-dotted and aromatic (Ranalean odor), hairs simple, branched or stellate, margins entire, stipules absent. Inflorescences terminal or axillary, sometimes cauliflorous, panicles, racemes, cymes, corymbs or fascicles; bracts mostly caducous, bracteoles present or not. Flowers small, unisexual (plants dioecious, rarely monoecious), actinomorphic, funnel-shaped, campanulate or urceolate; tepals (2-)3(-5) in 1 whorl, partly connate, often fleshy, whitish, greenish to yellow, valvate. Male flowers: stamens  3-12(-20), fused to a column (androphore), anthers adnate to column in different degrees, rarely free, anthers dehiscing by longitudinal slits. Female flowers: ovary superior, sessile or short stipitate, carpel and locule 1; style 1, distinct or absent; stigma 2-lobed; ovule 1, placentation basal or nearly so. Fruits baccate or drupaceous, usually dehiscent into 2-4 valves, rarely indehiscent, fleshy to coriaceous; seed 1, large; covered by fleshy aril, white, pink or red, laciniate or entire; endosperm usually ruminate.

Notes on delimitation

  • The Myristicaceae is placed in the order Magnoliales by Cronquist (1988). Molecular studies support this classification, placing the Myristicaceae as the sister-group of the clade formed by all the other families of the order (Stevens 2008).

Distribution in the Neotropics

In the Neotropics, the Myristicaceae is found mostly in lowland forest in the Amazon.

  • Compsoneura (A. DC.) Warb.: Central America to northern South America.
  • Iryanthera Warb.: Panama and northern South America (from Guianas to Peru and Bolivia).
  • Osteophloeum Warb.: northern South America.
  • Otoba (A. DC.) Karsten: Central America to northern South America.
  • Virola Aubl.: Central and South America.

Distinguishing characters (always present)

Other important characters

Key differences from similar families

  • Myristicaceae differs from Magnoliaceae mainly by: the presence of exudate, the absence of stipules, the inconspicuous flowers with few perianth parts and the flowers aggregated in inflorescences. In Magnoliaceae, the exudate is absent, the stipules are present, the flowers are large, solitary and with numerous perianth parts.
  • Myristicaceae can be mistaken for Annonaceae due to the myristicaceous branching and the alternate, distichous and exstipulate leaves; however the latter differs in lacking the red exudate (with rare exceptions), in having fibrous bark, numerous stamens and an apocarpous gynoecium.
  • Myristicaceae differs from Canellaceae mostly by: the presence of exudate, the unisexual flowers with few perianth parts, basal placentation and the capsular fruits.

Number of genera

  • Compsoneura (c. 12 spp.).
  • Iryanthera (c. 24 spp.).
  • Osteophloeum (1 sp.).
  • Otoba (c. 6 spp.).
  • Virola (c. 46 spp.).

Useful tips for generic identification

  • Compsoneura differs from all the other Neotropical genera by having the tertiary venation close-parallel and perpendicular to the midrib. It is also unique in having its seed-coat black or purple patterned. Indumentum of 2-branched hairs is present or the plant is glabrous. The stamens are few to many (4-10), the anthers adnate to column or free. The fruits are ellipsoid. The aril is red or white and entire (rarely laciniate).
  • Iryanthera has 2-branched hairs, although the leaves appear to be glabrous. The stamens are few (3-4(-6)), the anthers adnate to the column or free. The fruits are broader than wide (transversally ellipsoid) as in Osteophloeum. The aril is red and entire (or apically laciniate).
  • Osteophloeum is a monotypic genus (O. platyspermum) with straw-colored exudate. They are large trees with leaf apex distinctively round and petioles somewhat long. Stellate indumentum is present. The stamens are numerous (12(-20)), the anthers adnate to the column. The fruits are broader than wide (transversally ellipsoid) like Iryanthera, but differ in always having the aril entire.
  • Otoba usually has glaucous leaves on the lower surface. It has 2-branched hairs like Compsoneura and Iryanthera. The stamens are few (3(-4)), the anthers free of the column (or basally adnate). As in Virola, fruits are globose to ellipsoid. The aril is white and laciniate.
  • Virola has stellate indumentum, also present in the Osteophloeum. The leaves are usually oblong. The stamens are few (3(-4-6)), the anthers adnate to the column or apically free. The fruits are globose to ellipsoid. The aril is laciniate (as in Otoba) and red.

Notable genera and distinguishing features

  • Virola is the largest genus among Neotropical Myristicaceae. It also has the widest distribution and is especially important in the Amazon.

Status

  • Native.

General notes

  • All species of the family were placed in the single genus Myristica for a long time. Later, the family was divided in many genera, based mainly in the variations of the androecium, and also in inflorescence, aril and pollen.
  • Some authors consider the perianth parts as sepals (petals absent).
  • The exudate of several species of Virola is hallucinogenic.
  • The nutmeg spice is obtained from an Indonesian species of Myristica.

Important literature

Belota Filho, W.L. 1994. As espécies de Iryanthera Warburg ( Myristicaceae) da Reserva Florestal Ducke. Dissertação de Mestrado. INPA/FUA, Manaus. 94 pp.

Cronquist, A. 1988. An integrated system of the classification of flowering plants. Colombia University Press, New York.

Gentry, A.H. 1996. A Field Guide to the Families and Genera of Woody Plants of Northwest South America (Colombia, Ecuador, Peru) with Supplementary Notes on Herbaceous Taxa. Chicago and London, The University of Chicago Press. pp. 638-642.

Heywood, V.H., Brummit, R.K., Culham, A. & Seberg, O. 2007. Flowering Plant Families of the World. Royal Botanic Gardens, Kew. pp. 223-224.

Janovec, J. P. 2002. Compsoneura camilodiazii J. Janovec, an interesting new species from the Rio Cenepa area, Peru. Novon 12(3): 366-369.

Janovec, J.P. & Harrison, J.S. 2002. A morphological analysis of the Compsoneura sprucei complex (Myristicaceae), with a new combination for the Central American species Compsoneura mexicana. Syst. Bot. 27(4): 662-673.

Janovec, J.P. & Neil, A.K. 2002 [2003]. Studies of the Myristicaceae: an overview of the Compsoneura atopa complex, with descriptions of new species from Colombia. Brittonia 54(4): 251-261.

Kühn, U. & Kubitzki, K. 1993. Myristicaceae. In: K. Kubiztki, J.G. Rohwer & V. Bittrich (eds). The Families and Genera of Vascular Plants, Vol. II. Springer, Berlin Heidelberg New York. pp. 457-467.

Pennington, T.D., Reynel, C. & Daza, A. 2004. Illustrated guide to the trees of Peru. Sherborne, David Hunt. pp. 180-184.

Ribeiro, J.E.L.S., Hopkins, M.J.G., Vicentini, A., Sothers, C.A., Costa, M.A.S., Brito, J.M., Souza, M.A.D., Martins, L.H.P., Lohmann, L.G., Assunção, P.A.C.L., Pereira, E.C., Silva, C.F., Mesquita, M.R. & Procópio, L.C. 1999. Flora da Reserva Ducke: Guia de identificação das plantas vasculares de uma floresta de terra firme na Amazônia Central. INPA, Manaus. 816 pp.

Rodrigues, W.A. 1980. Revisão taxonômica das espécies de Virola Aublet (Myristicaceae) do Brasil. Acta Amaz. 10(1 supl.): 1-127.

Rodrigues, W.A. 1981. Nova Iryanthera Warb. (Myristicaceae) da Amazônia. Acta Amaz. 11(4): 852-854.

Rodrigues, W.A. 1989. Two new Neotropical species of Compsoneura (Myristicaceae). Brittonia 41(2):160-163.

Rodrigues, W.A. 1998. Reabilitação nomenclatural e taxonômica de Virola bicuhyba (Schott) Warb. Acta Bot. Brasil. 12(3): 249-252.

Rodrigues, W.A., Jaramillo, T.S., Muriel, P. & Balslev, H. 2001. Myristicaceae novelties from Ecuador. Nordic J. Bot. 20(4): 443-447.

Rodrigues, W.A. 2003. Notas taxonômicas sobre Myristicaceae neotropicais. Acta Biol. Par. Curitiba 31: 71-77.

Smith, A.C. & Woodhouse, R.P. 1937. The American species of Myristicaceae. Brittonia 2: 393-510.

Stevens, P.F. 2008. Angiosperm Phylogeny Website, version 9. http://www.mobot.org/MOBOT/research/APweb/.

Wilson, T.K. 2004. Myristicaceae. In: N. Smith, S.A. Mori, A. Henderson, D.W. Stevenson & S.V. Heald (eds). Flowering Plants of the Neotropics, pp. 261-262. New York Botanical Garden & Princeton University Press, Princeton.

Stevens, P.F. 2008. Angiosperm Phylogeny Website, version 9. http://www.mobot.org/MOBOT/research/APweb/.

How to cite

Sasaki, D. (2009). Neotropical Myristicaceae. 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/Myristicaceae.htm.