Systematics/Phytogeography / Taxonomie/ Section
Kiel, Carrie , Daniel, Thomas F. , McDade, Lucinda .
Relationships within the 'justicioid' lineage: Phylogenetic signal amid taxonomic chaos.
The 'justicioid' lineage (Acanthaceae: Justicieae) includes >1000 species and has a range that mirrors that of the entire family, occurring in tropical, subtropical and temperate regions worldwide. With limited taxon sampling, our previous work supported monophyly of the lineage, with a series of clades of Old World (OW) 'justicioids' basal to Diclipterinae + a clade of all sampled members of New World (NW) 'justicioids'. This result is surprising because 'justicioids' share a number of synapomorphic characteristics including a rugula (i.e., channel-like structure in the upper corolla lip that partially encloses the style) and anther 'complexity' (i.e., one or more of the following: thecae inserted at different heights on filaments, not parallel, one or the other sterile, one or both appendaged apically or basally). These results suggest that these traits have been lost in Diclipterinae. The present study expands the taxon sample more than 100%, with species chosen to represent nearly all recognized genera and proposed infrageneric taxa of the largest genus, Justicia. We used sequence data from five regions (nrITS; cp trnG-S, trn-L(uga)-ndhF, trnT-L, rps16) and analyzed these data using parsimony and Bayesian inference. Results confirm the sister relationship between NW 'justicioids' and Diclipterinae, the latter expanded to include a number of OW 'justicioids' that were not sampled previously. OW 'justicioids' form a series of clades basal to NW 'justicioids' + Diclipterinae. Few traditionally recognized genera are monophyletic and most of these are Diclipterinae (e.g., Dicliptera, Peristrophe, Hypoestes, Monechma, Rhinacanthus). Notably, Justicia is grossly polyphyletic with species placed in essentially all resolved clades except 'core' Diclipterinae. However, among OW plants, there is some congruence between phylogenetic results and relationships proposed by earlier workers (e.g., Aulojusticia + OW 'Siphonoglossa', Duvernoia + Adhatoda), as well as some infrageneric taxa of Justicia that correspond to clades.
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Acanthaceae Tree of Life
1 - Rancho Santa Ana Botanic Garden, Research, 1500 North College Avenue, Claremont, CA, 91711, USA
2 - California Academy of Sciences, Department of Botany, 875 Howard Street, San Francisco, California, 94103-3009, USA
3 - Rancho Santa Ana Botanic Garden, 1500 North College Avenue, Claremont, California, 91711, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, July 30th, 2008
Time: 11:30 AM