Perspectives in Plant Ecology, Evolution and Systematics Vol. 1/2, pp. 267–290 © Gustav Fischer Verlag, 1998 Systematics, biogeography and conservation of Lactoridaceae Tod F. Stuessy 1 *, Daniel J. Crawford 2 , Gregory J. Anderson 3 & Richard J. Jensen 4 1 Department of Higher Plant Systematics and Evolution, Institute of Botany, University of Vienna, Rennweg 14, 1030 Wien, Austria; 2 Department of Plant Biology, Ohio State University, 1735 Neil Avenue, Columbus, Ohio 43210, USA; 3 Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut 06269, USA; 4 Department of Biology, Saint Marys College, Notre Dame, Indiana 46556, USA; *corresponding author, email: tod.stuessy@univie.ac.at Abstract Lactoridaceae are a monotypic family confined to the Juan Fernandez (= Robinson Crusoe) Islands, Chile, an archipelago four million years old. Interest in the lone species, Lactoris fernandeziana, has increased in recent years due to its suspected role in early angiosperm evolution, as well as its endangered conservation status. Re- ports of fossil pollen of Lactoris (as Lactoripollenites) from deep sea sediments of Cretaceous age off the western coast of South Africa provide evidence for southern hemisphere occurrence of the family 70–90 million years ago. This age, plus trimer- ous symmetry and simple morphology of the flower with three tepals, six stamens and three nearly free carpels with laminar placentation, involve the family with hypotheses regarding evolution of early angiosperms, especially paleoherb and monocot diver- gences. Based on cladistic analyses with morphological and nucleotide data, recom- mended taxonomic placement of Lactoris is as a monotypic order, Lactoridales, allied most closely to Aristolochiales, and also near Piperales. Approximately 1000 individu- als of Lactoris are believed to exist, and genetic variation within and among popula- tions as measured by isozymes and RAPDs is low. This, in part, could be due to the self-compatibility and geitonogamous breeding system of this wind-pollinated species. More efforts at ex situ conservation should be attempted so that this impor- tant angiosperm family is maintained for future evolutionary studies. Key words: cladistic analyses, early angiosperm evolution, flower morphology, Juan Fernandez Islands, Lactoris fernandeziana Introduction Lactoridaceae (Fig. 1) are the only family of angiosperms confined to a volcanic oceanic island, on Masatierra Island of the Juan Fer- nandez (= Robinson Crusoe) archipelago, 667 km west of continental Chile (Fig. 2). De- generiaceae with two species are also re- stricted to an island archipelago, the Fiji Is- lands (Miller 1988, 1989), but these islands apparently arose from a fragmented island arc rather than being of oceanic volcanic ori- gin (Miller 1989). Because of morphological simplicity of flowers, Lactoridaceae have been placed in a number of different taxonomic groups. Cron- quist (1981) positioned the family in Magno- liales, as did Lammers et al. (1986), but other authors have favoured Laurales (Takhtajan 1980), Piperales (Melchior 1964) or even