skip to main content


The NSF Public Access Repository (NSF-PAR) system and access will be unavailable from 11:00 PM ET on Friday, April 12 until 2:00 AM ET on Saturday, April 13 due to maintenance. We apologize for the inconvenience.

Search for: All records

Creators/Authors contains: "Porter, J. Mark"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Abstract Background and Aims

    Few studies of angiosperms have focused on androecial evolution in conjunction with evolutionary shifts in corolla morphology and pollinator relationships. The Western Hemisphere clade of Justiciinae (Acanthaceae) presents the rare opportunity to examine remarkable diversity in staminal morphology. We took a phylogenetically informed approach to examine staminal diversity in this hypervariable group and asked whether differences in anther thecae separation is associated with phylogenetically informed patterns of variation in corolla morphology. We further discuss evidence for associations between anther diversity and pollinators in this lineage.


    For the Dianthera/Sarotheca/Plagiacanthus (DSP) clade of Western Hemisphere Justiciinae, we characterized floral diversity based on a series of corolla measurements and using a model-based clustering approach. We then tested for correlations between anther thecae separation and corolla traits, and for shifts in trait evolution, including evidence for convergence.

    Key Results

    There is evolutionary vagility in corolla and anther traits across the DSP clade with little signal of phylogenetic constraint. Floral morphology clusters into four distinct groups that are, in turn, strongly associated with anther thecae separation, a novel result in Acanthaceae and, to our knowledge, across flowering plants. These cluster groups are marked by floral traits that strongly point to associations with pollinating animals. Specifically, species that are known or likely to be hummingbird pollinated have stamens with parallel thecae, whereas those that are likely bee or fly pollinated have stamens with offset, divergent thecae.


    Our results suggest that anther thecae separation is likely under selection in concert with other corolla characters. Significant morphological shifts detected by our analyses corresponded to putative shifts from insect to hummingbird pollination. Results from this study support the hypothesis that floral structures function in an integrated manner and are likely subject to selection as a suite. Further, these changes can be hypothesized to represent adaptive evolution.

    more » « less