Neotropical Myricaceae

Description

Small trees or shrubs. Leaves alternate, simple, with entire or serrate/dentate margins, usually aromatic, containing pellucid punctuations and commonly with an indumentum of simple hairs and peltate, glandular scales; stipules absent.  Inflorescences borne in the leaf axils in catkins.  Flowers unisexual, perianth absent, subtended by bracts. Male flowers with 2-8 (-20) stamens (most commonly 4), anthers basifixed and dehiscing by longitudinal slits. Female flowers with syncarpous gynoecium (2 carpels), 2 (occasionally 3) stigmas, superior 1-locular ovary.  Fruit a one-seeded drupe or nutlet, sometimes enclosed in bracteoles and sometimes covered in a whitish waxy layer.

Notes on delimitation

• According to morphological and molecular analyses, the Myricaceae are closely affiliated to the Juglandaceae and fall within the Fagales (though sometimes considered in an order of their own - Myricales).

Distribution in the Neotropics

• Distributed throughout the Neotropics.
• Mainly in montane and submontane forests and páramo grasslands.
• Commonly on boggy ground.
• Sometimes in disturbed habitats.

Distinguishing characters (always present)

• Alternate, variably serrate leaves with pellucid punctuations and peltate scales (giving characteristic yellow gland -dotted appearance). No stipules.
• Inferior ovary; male and female flowers borne on catkins with no perianth.

Other important characters

• Fruit surface often tuberculate and sometimes coated with a waxy substance.
• Leaves often aromatic.
• Twigs usually strongly ridged.

Key differences from similar families

The Myricaceae could potentially be confused with other members of the Fagales, but differ from them in the following characters:

• From Fagaceae - drupaceous fruits; superior ovary; absence of perianth; glands and punctuations in leaves.
• From Betulaceae - drupaceous fruits; absence of stipules; superior ovary.
• From Juglandaceae - simple leaves; superior ovary.
• From Ticodendraceae - lack of stipules; pellucid punctuations in leaves; superior ovary.
• It is conceivable that in a vegetative state this family could be confused with Theaceae (which may also have serrate, punctuate leaves), but Theaceae punctuations are dark, even in bud, rather than pellucid.

Number of genera

• Traditionally only one genus in the Neotropics (Myrica L.), but taxonomists have recently reassigned the American species to the genus Morella Lour. (Parra-O, 2002)

Useful tips for generic identification

• A key to the South American species of Morella (including all previously assigned to Myrica) is given by Parra-O (2002).

Status

• Native.

General notes

• As in other parts of the world, the wax that coats the fruits of these plants has been exploited in the past for candle manufacture (removed by boiling).
• Nitrogen-fixing nodules are usually present in the roots, apparently helping to provide a competitive advantage in boggy areas.

Important literature

Manos, P. S. & Steele, K. P. 1997. Phylogenetic analyses of 'higher' Hamamelididae based on plastid sequence data. Amer. J. Bot. 84:1407-1419.

Parra-O, C. 2002. New combinations in South American Myrica. Brittonia 54(4): 322-326.

Roberts, A.S. 2004. Myricaceae, pp. 259-261. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. and Heald, S.V. (eds.). Flowering Plants of the Neotropics, p. 316. The New York Botanical Garden, Princeton University Press, Princeton.