Global advances in phylogeny, taxonomy and biogeography of Lauraceae

Abstract

Over the past two decades, our understanding of Lauraceae, a large family of woody plants, has undergone significant advances in phylogeny, taxonomy, and biogeography. Molecular systematic studies have elucidated the basic relationships within the family with plastid phylogenomic analyses providing robust support for deep-level relationships between Lauraceae lineages, leading to the recognition of nine tribes: Hypodaphnideae, Cryptocaryeae, Cassytheae, Neocinnamomeae, Caryodaphnopsideae, Mezilaureae, Perseeae, Laureae, and Cinnamomeae, with Mezilaureae validated here. Nuclear genomes and comparative genomics studies have also clarified aspects of the family's evolutionary history and metabolic diversity. Taxonomic studies have focused mainly on the most diverse regions, e.g., tropical Asia, tropical America, and Africa (Madagascar), with six new genera described and five reinstated since the last major overview of the family. The extensive fossil record suggests that Lauraceae diversified globally during the Late Cretaceous and Early Cenozoic. Biogeographic studies indicate that different lineages of the family are sorted into Gondwanan and Laurasian lineages, with patterns resulting from the disruption of boreotropical flora and multiple long-distance dispersal events. Phylogeographic studies, predominantly from East Asia, have shown patterns of in situ survival and demographic stability or expansion during the Quaternary. Nevertheless, many systematic relationships within the family remain unresolved and further research is needed into the complex biogeographic history and ecological roles of Lauraceae. A multifaceted approach integrating genomic studies, field work, morphological and ecological investigations is therefore needed to understand the evolution and diversity of this ecologically and economically significant plant family.

Keywords: Biogeography; Lauraceae; Phylogenomics; Phylogeny; Taxonomy.

Fig. 1

Species richness of georeferenced records in Lauraceae, based on data from GBIF (GBIF.org, 2024).

Fig. 2

Phylogenetic relationships among all recognized genera and tribes in Lauraceae. This tree summarizes results from several molecular phylogenetic investigations (Li et al., 2008c, 2011, 2020; Alves and Souza, 2013; Rohwer et al., 2014; Rohde et al., 2017; Song et al., 2020; Liu et al., 2021; Trofimov and Rohwer, 2020; Penagos Zuluaga et al., 2021; Yang et al., 2022, 2023). For those non-monophyletic genera, only one node is displayed, which includes the type species of each genus. Nodes resolved with 90%–100% bootstrap support or Bayesian posterior probabilities of 0.95–1.00 are shown with bold lines. Genera without molecular sampling are temporarily placed in possible positions and represented by dashed lines. Morphological characters are shown as diagrams following each tip, with explanation provided below. Representative photos are shown on the right: A. Cryptocarya; B. Beilschmiedia; C. Cassytha; D. Neocinnamomum; E. Caryodaphnopsis; F. Persea; G. Machilus; H. Laurus; I. Litsea; J. Iteadaphne; K. Neolitsea; L. Camphora; M. Cinnamomum; N. Aiouea; O. Nectandra; P. Ocotea; Q. Aniba. Photos credit: A–E and G–M by B. Liu (刘冰); F and N–Q by J.G. Rohwer.

Fig. 3

Examples of stamens and staminodes. A–C Hypodaphnis zenkeri (Engl.) Stapf; A. Stamen of whorl 1, adaxial side; B. Stamen of whorl 3, adaxial side; C. Gland complex alternating with the stamens of whorl 3, interpreted as staminode of whorl 4 fused to adjacent glands. D. Eusideroxylon zwageri Teijsm. & Binn., stamen of whorl 3, abaxial side; glands hardly discernible. E, F Aspidostemon glandulosus Rohwer; E. Stamen of whorl 1, adaxial side; F. Staminode of whorl 3, abaxial side, with attached glands. G–I Cryptocarya botelhensis P.L.R. Moraes; G. Stamen of whorl 2, with longitudinal septum inside the locules; H. Stamen of whorl 3, with stalked glands, abaxial side; I. Staminode of whorl 4 with cordate glandular head, adaxial side. J–L Ocotea tonduzii Standl.; J. Stamen of whorl 1, adaxial side; K. Stamen of whorl 3, abaxial side, with glands; L. Minute remnant of staminode of whorl 4. M, N Persea alpigena Spreng. var. harrisii (Mez) L.E. Kopp; M. Stamen of whorl 2, adaxial side, upper locules reduced or absent; N. Staminode of whorl 4 (left) and stamen of whorl 3 (right), abaxial side, with stalked glands. O, P Urbanodendron verrucosum (Nees) Mez; O. Stamen of whorl 2, adaxial side, lower locules reduced (or absent), filament with glands; P. Stamen of whorl 3, lateral view, lower locules reduced (or absent), filament with glands. Scale bar = 1 mm. Camera lucida drawings from herbarium material by Jens G. Rohwer [A–C Leeuwenberg 5557 (HBG); D Endert 15E2P680 (L); E, F Service Forestier 16534 (P); G–I Moraes 2329 (HBG); J–L Tonduz 1739 (B); M, N Harris 5335 (NY); O, P Kuhlmann s.n., RB91278 (RB)].

Fig. 4

Generalized inflorescence diagrams. A. Branch with thyrsoid inflorescence, i.e., proximally with one to several order(s) of racemose branching, distally with one to several orders of cymose (dichasial) branching. Inflorescences may be arranged in the axils of cataphylls below the terminal vegetative bud (top), and/or in the axils of foliage leaves (middle, right), and/or on axillary brachyblasts (lower left). Bracts within the inflorescence (blue) may or may not be present in mature inflorescences; B. Dibotryoid inflorescence, i.e., determinate double raceme, cymose part not developed; C. Botryoid inflorescence (determinate raceme); D. Inflorescence consisting of three flower triads; E. Pseudo-umbel, i.e., internodes in the inflorescence not elongating, except peduncle and pedicels; F. Same pseudo-umbel in bud, enclosed by its involucral bracts (externally looking like a flower bud).

Fig. 5

Inflorescence structures in the Laureae. Pseudo-umbels enclosed by their involucra represented by blue circles. A. Basic pattern; B. Brachyblast more elongate, with terminal bud; C. Brachyblast looking like a raceme of umbels; terminal bud aborted during development; D. Peduncles scarcely elongating, pseudo-umbels (sub)sessile. E. Fascicle of stalked pseudo-umbels, brachyblast scarcely elongating; F. Cluster of (sub)sessile pseudo-umbels around a vegetative bud, both brachyblast and peduncles scarcely elongating; G. Cluster of (sub)sessile pseudo-umbels, vegetative bud aborted during development.

Fig. 6

Floral parts of unisexual flowers of Ocotea lancifolia (Schott) Mez. A–C Staminate flower. A. Stamen whorl 1, adaxial side; B. Stamen of whorl 3, abaxial side; C. Pistillode. D–F Pistillate flower. D. Staminode of whorl 1, adaxial side; E. Staminode of whorl 3, abaxial side; F. Pistil. Scale bar = 1 mm. Camera lucida drawings from herbarium material by Jens G. Rohwer [A–C Glaziou 6666 (C); D–F Martius 1112 (M)].

Fig. 7

Major migration and dispersal events of Lauraeae lineages in Cenozoic, summarized from studies of Chanderbali et al. (2001), Li et al. (2011, , Huang et al. (2016), and Song et al. (2023). Green dotted lines: Laurasian lineages; Yellow dotted lines: Gondwanan lineages. Paleogeographic maps were modified based on Scotese (2014a, .