Mestre

Disponível somente no TrabalhosFeitos
  • Páginas : 50 (12297 palavras )
  • Download(s) : 0
  • Publicado : 6 de fevereiro de 2013
Ler documento completo
Amostra do texto
American Journal of Botany 92(9): 1520–1534. 2005.

MOLECULAR PHYLOGENETICS OF THE GIANT GENUS
CROTON AND TRIBE CROTONEAE (EUPHORBIACEAE
SENSU STRICTO) USING ITS AND TRNL-TRNF DNA
SEQUENCE DATA1

PAUL E. BERRY,2,5 ANDREW L. HIPP,3 KENNETH J. WURDACK,4
BENJAMIN VAN EE,2 AND RICARDA RIINA2
2
Department of Botany, University of Wisconsin–Madison, 430 Lincoln Drive, Madison, Wisconsin 53706USA; 3The Morton
Arboretum, 4100 Illinois Route 53, Lisle, Illinois 60532-1293 USA; and 4Department of Botany and Laboratories of Analytical
Biology, Smithsonian Institution, P.O. Box 37012, NMNH MRC-166, Washington, D.C. 20013-7012 USA

Parsimony, likelihood, and Bayesian analyses of nuclear ITS and plastid trnL-F DNA sequence data are presented for the giant
genus Croton (Euphorbiaceaes.s.) and related taxa. Sampling comprises 88 taxa, including 78 of the estimated 1223 species and 29
of the 40 sections previously recognized of Croton. It also includes the satellite genus Moacroton and genera formerly placed in tribe
Crotoneae. Croton and all sampled segregate genera form a monophyletic group sister to Brasiliocroton, with the exception of Croton
sect. Astraea, which isreinstated to the genus Astraea. A small clade including Moacroton, Croton alabamensis, and C. olivaceus is
sister to all other Croton species sampled. The remaining Croton species fall into three major clades. One of these is entirely New
World, corresponding to sections Cyclostigma, Cascarilla, and Velamea sensu Webster. The second is entirely Old World and is sister
to a third, also entirely NewWorld clade, which is composed of at least 13 of Webster’s sections of Croton. This study establishes a
phylogenetic framework for future studies in the hyper-diverse genus Croton, indicates a New World origin for the genus, and will
soon be used to evaluate wood anatomical, cytological, and morphological data in the Crotoneae tribe.
Key words:

Astraea; Croton; Crotoneae; Euphorbiaceae; giantgenus; ITS; molecular phylogenetics; trnL-F.

Croton (Euphorbiaceae s.s.) is one of the largest genera of
flowering plants, with between 1200 and 1300 species of
herbs, shrubs, trees, and occasionally lianas that are ecologically prominent and important elements of secondary vegetation in the tropics and subtropics worldwide (Webster, 1993;
Govaerts et al., 2000; Fig. 1). There ishorticultural confusion
with Codiaeum, a small and distantly related Malesian genus
of Euphorbiaceae whose common name ‘‘croton’’ refers to the
worldwide cultivated ornamental varieties of Codiaeum variegatum (L.) A. Juss. In the field, Croton is usually readily
recognizable by a suite of characters that includes conspicuous
stellate or scalelike trichomes, narrow or condensed inflorescences of unisexualflowers, watery to colored sap, frequent
petiolar glands, and senescent leaves that turn orange before
dehiscing. The diverse array of extrafloral nectaries in Croton
plays an important role in ant–plant interactions (viz., DeVries
and Baker, 1989). Pollination of the slender inflorescences
with clusters of unisexual flowers shifts between insects and
wind, and breeding systems vary from monoecy todioecy
(Domınguez and Bullock, 1989; Bullock, 1994; Decker and
´
Manuscript received 11 December 2004; revision accepted 2 May 2005.
The authors thank the following individuals who have provided plant material: Hans-Joachim Esser (M), Paul Forster (BRI), Dylan Hannon (RSA),
and Victor Steinmann (IEB). We also thank the curators of BRIT, DAV, MO,
NY, RSA, and US for allowing us to sampleherbarium and/or living material.
This work was funded in part by the National Science Foundation under Grant
No. DEB-0212481. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. Additional funding
came from the University of Wisconsin–Madison Graduate School....
tracking img