Lauraceae
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Family
Lauraceae (Magnoliophyta)
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Scientific Name
Lauraceae
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Common Names
Laurel Family
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Description
Number of genera: 30-50
Number of species: 2,000
Description (from PLANTAE): Trees, sometimes shrubs, rarely parasitic vines, mostly evergreen. Bark usually smooth, aromatic. Stems mostly erect, sometimes with small, stilt-root buttresses; glabrous or with simple hairs. Stipules absent. Leaves usually alternate (spiral), sometimes opposite or subopposite, simple, often aromatic, rarely scale-like; blades generally coriaceous, often with translucent gland dots, the margins entire; venation pinnate or rarely palmate. Infloresnence usually axillary, usually compound, sometimes 1-few-flowered or capitate by reduction of axes. Flowers actinomorphic, bisexual, unisexual or functionally unisexual, plants monoecious or dioecious, usually 3-merous, small, yellow, green or whitish, rarely reddish; receptacle generally well developed and fleshy; tepals generally 6, in 2 whorls of 3; androecium generally in 4 whorls of 3 stamens each, the inner-most generally staminodial, the third often with paired, nectariferous glands at the base, the anthers introrse or extrorse, 2- or 4-locular, dehiscing by hinged flaps, opening upwards; receptacle small or enlarged and urceolate; ovary usually superior, often enclosed in receptacle, the carpel 1, the locule 1, the style 1, short, the stigma 1, discoid or inconspicuous. Fruits drupes, subtended or partially to completely enclosed by the enlarged, often reddish receptacle, the exocarp often glossy, black, brown or purple, often contrasting with the receptacle. Seeds large, with large cotyledons and embryos
Taxonomic notes (from PLANTAE): The family is here divided into two groups: the Laureae and Perseae, separable by inflorescence type (Laureae-racemose or umbellate, involucrate; Perseae-thyrsoid, not involucrate), however the Perseae may be artificial. The anomalous Cassytha, with its parasitic, vining habit is unique in the family, but generally regarded as an offshoot of Cryptocarya in the Perseae. An alternate and common subdivision places Cassytha in a group by itself with the remainder of the family in another group, or Cassytha is separated as a distinct family. Specimens are notoriously difficult to assign to genus. The genera are often defined by androecial characters such as the number of staminal whorls, staminodial characters, number of locules in the anther, and the number and orientation of flaps. Certain identification to genus often requires both flowers and fruit-- a condition almost never encountered simultaneously [See Rohwer, J. G. 2000. Toward a phylogenetic classification of the Lauraceae: Evidence from matK sequences. Systematic Botany 25: 60-71.]
Distribution (from PLANTAE): Pantropical with centers of diversity in tropical America and southeast Asia. Some are subtropical, a few species reach the temperate zone in the northern and southern hemispheres.
Economic uses (from PLANTAE): Most species are probably obligate outcrossers. Perfect flowers are protogynous and those of a particular species may be in two classes. One class is functionally female in the morning and functionally male in the afternoon, while the individuals of the other class are functionally female in the afternoon and male the following morning. Insects (often flies) are attracted to the androecial nectar glands and may pick up pollen copiously attached to upturned flaps. The fruits are rich in lipids, minerals and carbohydrates and are important food sources for birds and mammals. Frugiverous birds such as quetzals, toucans and oilbirds are often highly dependent on the fruit, with up to 80% of their diet coming from Lauraceae fruit. Birds migrating between the temperate and tropical zones will find Lauraceae fruit throughout their journey-- particularly between temperate and tropical America. Economically important products include the avocado (Persea americana), cinnamon and camphor (Cinnamomum) and bay leaf (Laurus nobilis). The avocado as we know it is one of the most imporant plant products developed by indigenous Americans. Like cacao (Theobroma cacao), it is believed to have originated in southern Mexico and Guatemala. Grafting technology has improved yields and made plantations possible. A few species are used for timber. Many species are used locally for medicine.
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Floras and Monographs
Lauraceae: [Book] Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.