Myrtaceae

Read about Myrtaceae in the Standard Cyclopedia of Horticulture

Myrtaceae (from the genus Myrtus derived from the classical name myrtle, which probably meant perfume). Myrtle Family. Fig. 43. Usually shrubby or arborescent aromatically fragrant plants: leaves usually opposite, thick, entire and pellucid-dotted: flowers bisexual, regular, rarely perigynous; sepals mostly 4-5, imbricated; petals 4-5, imbricated; stamens very numerous by splitting, often in fascicles which are opposite the petals; ovary inferior, 1- to many-celled: fruit usually a berry, rarely a drupe or nut; seeds 1- to many. The 72 genera and 2,750 species are confined almost entirely to the tropics, but with two great centers of distribution, one in tropical America and the other in Australia. Eugenia contains 625 species, and Eucalyptus more than 130 species. This is a large family related to the Melastomaceae, Onagraceae, and Lythraceae. The very numerous stamens, derived by the splitting of the few original stamens, and the oil-glands are distinctive. The petals of Eucalyptus remain firmly grown together, and, when the flower opens, they separate along a transverse line and are thrown off as a lid. The Myrtaceae are rich in volatile oils; also in tannin, acids, sugars, mucilage, and fixed oils. Cloves are the flower-buds of Jambosa caryophyllus. The fruit of Pimenta officinalis is thought to combine the flavors of the nutmeg, cinnamon, and clove, and is therefore termed allspice. Psidium Guajava is a tree cultivated in the tropics for the much-prized fruits. Oil of myrica is obtained from the leaves of Pimenta acris of the West Indies, and is used in making bay rum. Oil of cajeput, a fragrant oil used in medicine, is secured from the leaves and twigs of the East Indian Melaleuca Leucadendron. The leaves of the European myrtle (Myrtus communis) yield a distilled preparation known as eau-d'ange, used as a toilet article. Other edible fruits are rose apples (Jambosa malaccensis and J. vulgaris) of the East Indies and Pacific Ocean. Jambos berries are obtained from Jambosa vulgaris, which is extensively cultivated in the tropics. Oil of eucalyptus is an important aromatic oil obtained from the foliage of various species of that genus. The wood of Eucalyptus is hard, firm and elastic, and is much prized in wood-carving. Many other species of this family are in use locally for food, condiments, medicine, timber, and so on. About 20 genera are in cultivation in North America, mostly in the South or Southwest. Among these are the Bottle-brush (Callistemon), Cajaput Tree (Mela-leuca), Eucalyptus or Australian Blue-gum, Rose Apple or Jambos (Jambosa), Cayenne Cherry (Eugenia), Myrtle (Myrtus), Guava (Psidium), Allspice, Pimento (Pimenta), Brisbane Box (Tristania), Turpentine Tree (Syncarpia), and Downy Myrtle (Rhodomyrtus). CH The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.

? Myrtle family
Myrtus communis foliage and flowers
Plant Info
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Myrtales Family: Myrtaceae Juss.
Genera
About 130; see list

The Myrtaceae or Myrtle family are a family of dicotyledon plants, placed within the order Myrtales. Myrtle, clove, guava, feijoa, allspice, and eucalyptus belong here. All species are woody, with essential oils, and flower parts in multiples of four or five. One notable character of the family is that the phloem is located on both sides of the xylem, not just outside as in most other plants. The leaves are evergreen, alternate to mostly opposite, simple, and usually with an entire (not toothed) margin. The flowers have a base number of five petals, though in several genera the petals are minute or absent. The stamens are usually very conspicuous, brightly coloured and numerous.

The family Myrtaceae has at least 3000 species distributed in 130-150 genera. They have a wide distribution in tropical and warm-temperate regions of the world, and are typically common in many of the world's biodiversity hotspots. Genera with capsular fruits such as Eucalyptus, Corymbia, Angophora, Leptospermum, Melaleuca, Metrosideros are absent from the Americas, apart from the monotypic genus Tepualia in Chile. Genera with fleshy fruits have their greatest concentrations in eastern Australia and Malesia (the Australasia ecozone) and the Neotropics. Eucalyptus is a dominant, nearly ubiquitous genus in the more mesic parts of Australia and extends north sporadically to the Philippines. Eucalyptus regnans is the tallest flowering plant in the world. Other important Australian genera are Callistemon (bottlebrushes), Syzygium, and Melaleuca (paperbarks). The genus Osbornia, native to Australasia, are mangroves. Eugenia, Myrcia, and Calyptranthes are among the larger genera in the neotropics.

Historically, the Myrtaceae were divided into two subfamilies.

• Subfamily Myrtoideae have fleshy fruits and opposite, entire leaves. Most genera in this subfamily have one of three easily recognized types of embryos. The genera of Myrtoideae can be very difficult to distinguish in the absence of mature fruits. The Myrtoideae are found worldwide in subtropical and tropical regions, with centres of diversity in the Neotropics, northeastern Australia, and Malesia.
• Subfamily Leptospermoideae has dry, indehiscent fruits (capsules) and leaves arranged spirally or alternate. The Leptospermoideae are found mostly in Australasia, with a centre of diversity in Australia. Many genera in Western Australia have greatly reduced leaves and flowers typical of more xeric habitats.

The division of the Myrtaceae into the Leptospermoideae and Myrtoideae was challenged by a number of authors, including Johnson and Briggs (1984), who identified 14 tribes or clades within the Myrtaceae, and found the Myrtoideae to be polyphyletic. A molecular analysis by Wilson, O'Brien et al. (2001) found eleven strong groupings within the family, including many of the groupings identified by Johnson and Briggs. Further molecular analysis by Sytsma and Litt (2002) found that the Neotropic Myrtoideae grouping fit within the paraphyletic Leptopermoideae.

The genera Heteropyxis and Psiloxylon, which some authorities include in Myrtaceae, are here placed as separate families by most authors, based on evidence of their divergence before the origin of the common ancestor of the Myrtaceae.

Genera

Accara Acmena Acmenosperma Actinodium Agonis Allosyncarpia Amomyrtella Amomyrtus Angasomyrtus Angophora Archirhodomyrtus Arillastrum Astartea Asteromyrtus Austromyrtus Backhousia Baeckea Balaustion Barongia Basisperma Beaufortia Blepharocalyx Callistemon Calothamnus Calycolpus Calycorectes Calyptranthes Calyptrogenia Calythropsis Calytrix Campomanesia Carpolepis Chamelaucium Chamguava Choricarpia Cleistocalyx Cloezia Conothamnus Corymbia Corynanthera Cupheanthus Darwinia Decaspermum Eremaiea

Eucalyptopsis Eucalyptus Eugenia Feijoa (syn. Acca) Gomidesia Gossia Hexachlamys Homalocalyx Homalospermum Homoranthus Hottea Hypocalymma Kania Kjellbergiodendron Kunzea Lamarchea Legrandia Lenwebbia Leptospermum Lindsayomyrtus Lithomyrtus Lophomyrtus Lophostemon Luma Lysicarpus Mallostemon Marlierea Melaleuca Meteoromyrtus Metrosideros Micromyrtus Mitranthes Mitrantia Monimiastrum Mosiera Myrceugenia Myrcia Myrcianthes Myrciaria Myrrhinium Myrtastrum Myrtella Myrteola

Myrtus Neofabricia Neomitranthes Neomyrtus Ochrosperma Octamyrtus Osbornia Paramyrciaria Pericalymma Phymatocarpus Pileanthus Pilidiostigma Piliocalyx Pimenta Pleurocalyptus Plinia Pseudanamomis Psidium Purpureostemon Regelia Rhodamnia Rhodomyrtus Rinzia Ristantia Scholtzia Siphoneugena Sphaerantia Stereocaryum Stockwellia Syncarpia Syzygium Taxandria Tepualia Thryptomene Tristania Tristaniopsis Ugni Uromyrtus Verticordia Waterhousea Welchiodendron Whiteodendron Xanthomyrtus Xanthostemon

References

• Johnson, L.A.S. and Briggs, B.G. 1984. Myrtales and Myrtaceae – a phylogenetic analysis. Annals of the Missouri Botanic Garden 71: 700-756.
• Wilson, Peter G., O'Brien, Marcelle M., Gadek, Paul A., and Quinn, Christopher J. 2001. "Myrtaceae Revisited: A Reassessment of Infrafamilial Groups". American Journal of Botany 88 (11): 2013–2025. Available online (pdf file).
• Sytsma, Kenneth J. and Amy Litt. 2002. Tropical disjunctions in and among the Myrtaceae clade (Myrtaceae, Heteropyxidaceae, Psiloxylaceae, Vochysiaceae): Gondwanan vicariance or dispersal? (Abstract). Botany 2002 Conference, University of Wisconsin, Madison, Wisconsin, August 4-7 2002.