The Laurales consist of seven families, 84-88 genera, and about 2850 species. Previous studies on the morphology, anatomy, and palynology of Laurales have failed to satisfactorily resolve family relationships. Sequences from three regions of the plastid genome, the rbcL gene, the trnL-trnF intergenic spacer, and the rpl16 intron (comprising 2614 bp and 350 parsimony-informative characters), have been produced for 24 genera, with 5 of the 7 families represented by all their genera, as well as representatives of the related order Magnoliales. Spacer and intron sequences of Amborellaceae and Chloranthaceae, which have sometimes been placed in Laurales, can not be aligned with the remaining lauralean and magnolialean sequences. A parsimony analysis yields a well-supported tree in which the mostly temperate Calycanthaceae are sister to a clade comprising the remaining predominantly tropical families. The tropical group consists of two subclades, the Lauraceae-Monimiaceae-Hernandiaceae (LAU-MON below) and the Siparunaceae- (Atherospermataceae-Gomortegaceae) (ATH-SIP). The molecular tree is congruent with the following characters: (1) The Calycanthaceae have disulculate columellate pollen while the tropical clade has inaperturate thin-exined pollen; a hard-to-explain return? to columellate but meridionosulcate pollen occurred in Atherospermataceae. (2) The ATH-SIP clade has basal ovules (lost in Gomortega) while the LAU-MON clade has apical ovules. (3) Nectar glands on the filaments are either ancestral in the tropical clade and were lost twice, or else evolved twice and were lost once. Pollinator changes away from nectar-foraging bees in Monimiaceae and Siparunaceae argue for the first scenario. (4) Anther dehiscence by two valves is ancestral in the ATH-SIP clade and evolved independently in Hernandiaceae and within Lauraceae. (5) A chromosome number of n = 11 or 12 appears ancestral in Laurales, with double that number characterizing the ATH-SIP clade and polyploid series the Hernandiaceae and Monimiaceae.

Key words: Laurales, molecular phylogeny, Monimiaceae, rbcL, rpl16, trnL-trnF