Am. J. Bot.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (5)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Marazzi, B.
Right arrow Articles by Conti, E.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Marazzi, B.
Right arrow Articles by Conti, E.
Agricola
Right arrow Articles by Marazzi, B.
Right arrow Articles by Conti, E.
(American Journal of Botany. 2006;93:288-303.)
© 2006 Botanical Society of America, Inc.

Systematics and Phytogeography

Phylogenetic relationships within Senna (Leguminosae, Cassiinae) based on three chloroplast DNA regions: patterns in the evolution of floral symmetry and extrafloral nectaries1

Brigitte Marazzi4, Peter K Endress, Luciano Paganucci de Queiroz and Elena Conti

2Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland; 3Depto de Ciências Biológicas, Universidade Estadual de Feira de Santana, Km 03, BR 116, Campus, 44031–460, Feira de Santana, Bahia, Brazil

ABSTRACT

Senna (Leguminosae) is a large, widespread genus that includes species with enantiostylous, asymmetric flowers and species with extrafloral nectaries. Clarification of phylogenetic relationships within Senna based on parsimony analyses of three chloroplast regions (rpS16, rpL16, and matK) provides new insights on the evolution of floral symmetry and extrafloral nectaries. Our results support the monophyly of only one (Psilorhegma) of the six currently recognized sections, while Chamaefistula, Peiranisia, and Senna are paraphyletic, and monotypic Astroites and Paradictyon are nested within two of the seven major clades identified by our molecular phylogeny. Two clades (I, VII) include only species with monosymmetric flowers, while the remaining clades (II–VI) contain species with asymmetric, enantiostylous flowers, in which either the gynoecium alone or, in addition, corolla and androecium variously contribute to the asymmetry. Our results further suggest that flowers were ancestrally monosymmetric with seven fertile stamens and three adaxial staminodes, switched to asymmetry later, and reverted to monosymmetry in clade VII. Fertility of all 10 stamens is a derived state, characterizing the Psilorhegma subclade. Extrafloral nectaries evolved once and constitute a synapomorphy for clades IV–VII ("EFN clade"). These nectaries may represent a key innovation in plant defense strategies that enabled Senna to undergo large-scale diversification.

Key Words: Cassiinae • extrafloral nectaries • floral asymmetry • key innovation • matK gene • rpL16 intron • rpS16 intron • Senna




This article has been cited by other articles:


Home page
 Am. J. Bot.Home page
B. Marazzi and P. K. Endress
Patterns and development of floral asymmetry in Senna (Leguminosae, Cassiinae)
Am. J. Botany, January 1, 2008; 95(1): 22 - 40.
[Abstract] [Full Text] [PDF]

Home page
 J Exp BotHome page
Flowering Newsletter bibliography for 2006
J. Exp. Bot., April 20, 2007; (2007) erm028v2.
[Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2006 by the Botanical Society of America, Inc.