Myristicaceae R.Br.

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Distribution

A pantropical family with 19 genera and approximately 500 species; in New Guinea six genera are found including the New Guinea endemic genus Paramyristica.

Ecology

Most species are trees of lowland rain forest, but in New Guinea several species reach montane forests with some Horsfieldia and Myristica species reaching c. 2000 m.

Recognition

Members of the family are recognised by the red or orange sap, extipulate and alternate leaves, the unisexual, small flowers with fused inconspicuous tepals and, especially, the fruit dehiscing along a single suture, with a single seed covered with a brightly coloured aril.

Morphology General Habit

Trees, very rarely shrubs/climbers, with branches radiating horizontally from the main vertical axis

Morphology Twigs

Twigs/branchlets often dark with a striate surface or smooth and green, cross-section showing rays in the wood

Morphology General

Sap red or orange from cut surfaces (sometimes blood-like). Hairs, where present, simple or branched (stellate or T-shaped)

Morphology Leaves Stipules

Stipules absent

Morphology Leaves

Leaves simple, alternate (spirally or distichously arranged), margins entire, brittle when dry, often large and oblong, often glaucous (pale) below with inconspicuous tertiary venation

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, occasionally cauliflorous, generally branched (racemose or cymose)

Morphology Reproductive morphology Flowers

Flowers unisexual (plants dioecious or monoecious), very small, yellowish, white, pink or red, 3-merous; tepals inconspicuous, fused, lobes valvate; filaments fused, often into a column (synandrium); ovary superior with a single basal ovule

Morphology Reproductive morphology Fruits

Fruit fleshy to coriaceous, usually dehiscing along a single suture, with the single seed at the base

Morphology Reproductive morphology Seeds

Seed large (‘nutmeg’); covered with brightly coloured, yellow/red/orange, branched or entire aril (‘mace’); endosperm ruminate.

Sasaki, D. (2009). Neotropical Myristicaceae.

Morphology

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 . Maleflowers: 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 .

Distribution

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.

Diagnostic

Distinguishing characters (always present)

• Exudate present in the trunk (watery, usually red).
• Leaves simple and alternate.
• Stipules absent.
• Flowers unisexual, inconspicuous, actinomorphic.
• Stamens fused in a column (sometimes anthers partially or totally free).
• Ovarysuperior, 1-carpelled.
• Seed 1, large, with red or white aril.

Other important characters

• Plants usually aromatic (leaves gland -dotted).
• Branched or stellate hairs often present.
• Inflorescences sometimes cauliflorous (or terminal or axillary).
• Fruits dehiscent (rarely indehiscent).

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 fibrousbark, 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.

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. Stellateindumentum 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 arilentire.
• 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 stellateindumentum, 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.

General Description

Number of genera

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

Status

• Native.

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).

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.

Literature

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 Virolabicuhyba (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/.

Myristicaceae, B.L. Stannard. Flora Zambesiaca 9:2. 1997

Morphology General Habit

Trees or shrubs, rarely lianes, evergreen or rarely deciduous, often aromatic, dioecious or monoecious, sap coloured

Morphology Leaves

Leaves alternate, simple, entire, often gland-dotted; exstipulate

Morphology General Indumentum

Indumentum of stellate-branching, shortly-stalked T-shaped or uniseriate hairs

Morphology Reproductive morphology Inflorescences

Inflorescences paniculate, fasciculate-racemose, or capitate, sometimes apparently cymose; bracts often present, usually deciduous, bracteoles mostly absent

Morphology Reproductive morphology Flowers

Flowers unisexual, small, actinomorphic, whitish-yellow, pink or red; perianth saucer- or funnel-shaped, campanulate or urceolate, (2)3–4(5)-valvately lobed Female flowers 1-carpellate; ovary superior, usually sessile; style small or absent; stigmas ± 2-lobed; ovule 1, usually anatropous Male flowers with 2–30(40) stamens; filaments partially or completely fused into a column; anthers laterally connate, rarely free, 2-thecous, dehiscing by longitudinal slits; rudimentary ovary absent

sex Male

Male flowers with 2–30(40) stamens; filaments partially or completely fused into a column; anthers laterally connate, rarely free, 2-thecous, dehiscing by longitudinal slits; rudimentary ovary absent

sex Female

Female flowers 1-carpellate; ovary superior, usually sessile; style small or absent; stigmas ± 2-lobed; ovule 1, usually anatropous

Morphology Reproductive morphology Fruits

Fruits a drupe with a fleshy or leathery pericarp, mostly dehiscing into 2 valves

Morphology Reproductive morphology Seeds

Seeds partially or completely enveloped by an often brightly coloured laciniate or subentire fleshy aril; testa usually in 3 layers, the outer membranous or fleshy, the middle one woody and the inner one membranous, usually intruding into the folds of the endosperm; endosperm abundant, entire or ruminate, very oily; embryo very small with basal suberect, spreading or connate cotyledons

Myristicaceae, Hutchinson and Dalziel. Flora of West Tropical Africa 1:1. 1954

Morphology General Habit

Trees, often large and frequently aromatic

Morphology Leaves

Leaves alternate, entire, penninerved, often with pellucid dots; stipules absent

Morphology Reproductive morphology Flowers

Flowers small, dioecious, apetalous, fascicled, racemose, umbellate or capitate Male flower: stamens 2–30; filaments united into a column; anthers 2-celled, free or united in a mass, dehiscing longitudinally; rudimentary ovary absent Female flower: staminodes absent; ovary superior, sessile, 1-celled; stigma subsessile; ovule 1, almost basal

Morphology Reproductive morphology Flowers Calyx

Calyx 3- (rarely 2–5–) lobed, funnel-shaped to globose or saucer-shaped, lobes valvate

sex Male

Male flower: stamens 2–30; filaments united into a column; anthers 2-celled, free or united in a mass, dehiscing longitudinally; rudimentary ovary absent

sex Female

Female flower: staminodes absent; ovary superior, sessile, 1-celled; stigma subsessile; ovule 1, almost basal

Morphology Reproductive morphology Fruits

Fruit fleshy, usually dehiscing by two valves

Morphology Reproductive morphology Seeds

Seeds erect, with a thin or fleshy, sometimes laciniate, often coloured aril; endosperm copious, replete with fat and often starch, mostly ruminate; embryo small; cotyledons ascending or spreading, sometimes connate