You can manage bookmarks using lists, please log in to your user account for this.
Media type:
E-Article
Title:
Floral Development and Anatomy ofAextoxicon punctatum(Aextoxicaceae‐Berberidopsidales): An Enigmatic Tree at the Base of Core Eudicots
Contributor:
Ronse De Craene, Louis P.;
Stuppy, Wolfgang
imprint:
The University of Chicago Press, 2010
Published in:International Journal of Plant Sciences
Language:
English
DOI:
10.1086/650161
ISSN:
1058-5893;
1537-5315
Origination:
Footnote:
Description:
<p>Floral development and anatomy were investigated in the monotypic Aextoxicaceae (one species:<italic>Aextoxicon punctatum</italic>), one of two families of Berberidopsidales, to understand its putative relationship with Berberidopsidaceae and clarify floral evolution in basal core eudicots.<italic>Aextoxicon</italic>is dioecious, with unisexual flowers that display a late abortion of male and female organs in the respective genders. Flowers are pentamerous or hexamerous and are enclosed by a calyptra derived from the congenital fusion of two bracteoles. Initiation sequence and number of sepals, petals, and stamens are variable and mostly spiral, without clear transition between organ categories, and a single carpel initiates without evidence of a second carpel. The ovary contains two apical‐marginal ovules. Floral anatomical data suggest that the nectaries are receptacular in nature.<italic>Aextoxicon</italic>displays floral characters found in basal angiosperms, such as a unicarpellate gynoecium, an interrupted hoodlike outer integument, little differentiation between sepals and petals, and a transition of a decussate to spiral phyllotaxis at the level of sepals. These data indicate that<italic>Aextoxicon</italic>, together with Berberidopsidaceae, might represent a basal transitional lineage of basal to core eudicots and evidence that pentamerous flowers with a biseriate perianth evolved from progenitors with a comparable floral structure.</p>