PHYLOGENETIC RELATIONSHIPS OF THE LITSEA COMPLEX CORE LAUREAE (LAURACEAE) USING ITS AND ETS SEQUENCES AND MORPHOLOGY

Li, Jie

ANNALS OF THE MISSOURI BOTANICAL GARDEN

2008

95

4

Conran, JG

Nuclear DNA ITS and ETS sequences of 71 representatives from nine genera and 11 section of the core Laureae were combined with a matrix of morphological characters, analyzed using maximum parsimony with both equally and successively weighted characters, and analyzed for Bayesian inference, minimum evolution by neighbor joining, and maximum likelihood inference for molecular data alone. The large genera Actinodaphne Nces, Lindera Thumb, and Listen Lam. were polyphyetic , as were Lindera sect. Aperula (Blume) Benth. and Litsea sections Conodaphne (Blume) Benth & Hook f., Cylicodaphne (Nees) Hook f., and Tomingodaphne (Blume) Hook. f. In contrast, Neolitsea (Benth.) Merr was monophyletic and terminal in a alarger monophyletic lineage above an Actinodaphne grade. A major dispartiy exists between these molecular results and traditional morphology-based classifications within Lauraccac. These results suggest that the use of two- versus four-celled antheers for Laureac generic delimilation has resulted in polyphyletic of paraphyletic genera, and the character of dimerous versus trimerous flowers is of only limited phylogenetic value. Several of the major lineages in Laureae are supported by inflorescence morphology and ontogeny, with Laureae defined by short shoots with a vegetative terminal bud, splitting into thyrsoid (Actinodaphne and Neolistea) versus raccmose (Laurus. Litsea s.slr., and Lindera s. slr. and Lindera seet. Aperula), although there appear to be at least two different pathways to form the Laurcac pseudo-umbel. Similarly, imbricate, early deciduous inflorescence basal involucral bracts defined an Actionodaphne-Neolitsea-Parasasafrus-Sinosassafras clade, although within it, Neolisten was defined in part by decussale, persistent bracts. Accordingly, our study indicates the need for caution in the use of morphology for assessing affinity in Laureae, as virtually all traditional morphological characteristics show high levels of homoplasy and/or reversal, but future research may help to resolve whether this indicates problems of homology or ontogenetic convergence.