TOWARD AN IMPROVEDCLASSIFICATION OFLAURACEAE1Henk van der Werff andH. G. Richter3ABSTRACT Published suprageneric classifications of Lauraceae and the characters used in these classifications are brieflyreviewed. It is concluded that androecial characters such as number of stamens and number of anther cells areoften variable even within genera and that these characters should not be used in a classification of Lauraceae.As a first step toward an improved classification, Lauraceae are divided into two subfamilies, one consisting ofCassytha, the other including ail other genera. The latter group is divided into three tribes, the Laureae, Perseeae,and Cryptocaryeae, based on characters of wood and bark anatomy and inflorescence structure. Lauraceae form a large, predominantly tropicalfamily of trees and shrubs, with the exception ofCassytha, an herbaceous parasite. The family isbest represented in the American and Asian trop-ics, and has also a rather large number of speciesin Australia and Madagascar, but is poorly rep-resented in Africa. About 50 genera are currentlyrecognized, with 2500-3000 species. Economically, Lauraceae are an importantgroup. Many species yield high-quality timber,others spices or aromatic oils, and Persea amer-icana Miller is cultivated worldwide for its ediblefruits. Ecologically, Lauraceae are, in the New World,a very important group. They are present in wetforest at any elevation (from sea level to pdramos)and are frequently the most common or one ofthe most common tree families, especially in thefoothills and at middle elevations of the Andes. In spite of their importance, Lauraceae are, inrespect to classification and species numbers,poorly known. Our lack of knowledge of speciesnumbers and distribution is no doubt related tothe fact that many species are tall trees withsmall, inconspicuous flowers, difficult to locateand to collect. This is clearly shown by a recentfloristic treatment (Australia: 115 species, ofwhich 46 were new, Hyland, 1989), recent revi-sions (Nectandra: 114 species, of which 33 werenew, Rohwer, 1993a; Pleurothyrium: 40 species,of which 20 were new, van der Werff, 1993), andthe fact that in the most recent monograph of An-iba (Kubitzki, 1982) not a single collection wasrecorded from Ecuador, while currently 11 spe-cies are known from that country. More intensivecollecting will hopefully correct this lack ofknowledge. Lauraceae have, with a few exceptions, trim-erous flowers. Flowers are bisexual or unisexual.There are two whorls of three tepals; the whorlsare usually equal in size and shape, but in somecases the whorls are unequal. If the whorls areunequal, the outer whorl is usually smaller thanthe inner one, although the reverse can also bethe case. Flowers have four whorls of three sta-mens, but in most genera, one, two, or threewhorls are reduced to staminodia. The anthersopen by two or four valves. The ovary is generallysuperior, with one locule and one ovule, and thefruit, a one-seeded berry, sits either free on apedicel, is partially enclosed by persistent tepalsor the receptacle, or is entirely enclosed by thereceptacle.CLASSIFICATION OF LAURACEAE Strictly speaking, there is no lack of suprage-neric classifications of Lauraceae. Ail have incommon one characteristic: they are not widelyaccepted. We will present a brief review of theseclassifications and list the main characters usedin making them. The position of Cassytha in thedifferent classifications will not be discussed; itis always separated from the other Lauraceae be-cause of its herbaceous, parasitic habit, and weplace it in its own subfamily, the Cassythoideae. ' John Myers assisted in the preparation of the figures. We thank Tom Wendt for critical comments on an earlierversion of the manuscript. 2 Missouri Botanical Garden, P.O. Box 299, St. Louis, Missouri 63166-0299, U.S.A. Institut for Holzbiologie und Holzschutz, Bundesforschungsanstalt fur Forst-und Holzwirtschaft, LeuschnerstraBe91, 2050 Hamburg 80, Germany. ANN. MISSOURI BOT. GARD. 83: 409-418. 1996.
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