Abstract Detail

Systematics Section/ASPT

Kiel, Carrie A. [1], McDade, Lucinda [2].

The evolution of androecial form in the 'justicioid' lineage (Acanthaceae).

The monophyletic ‘justicioid’ lineage includes members of pantropical Justicia, the largest genus in Acanthaceae (ca. 600 spp). In this lineage, floral morphology, including size and color, as well as inflorescence structure are remarkably diverse, mirroring that of the entire family. In addition, Justicia is particularly intriguing because it is the only group among Acanthaceae that demonstrates remarkable variability in anther morphology: the two stamens may have thecae that are parallel, equal and unappendaged or that have expanded connective tissue and are unequal and/or displaced, and appendaged in various ways. In this study, we sampled ca. 150 taxa from the ‘justicioid’ lineage chosen to represent morphological diversity and geographical distribution, as well as all recognized sections of Justicia from both the Old World (OW) and New World (NW). Using maximum likelihood criteria and a Bayesian framework, we confirm earlier results that Justicia is highly polyphyletic. However, all sampled NWJusticia are together monophyletic with strong support. Both floral and anther morphological diversity are centered in the NW Justicia lineage. Our results strongly suggests that this morphological disparity is correlated with pollination syndromes. NW Justicia with hummingbird-pollinated flowers often have thecae that are parallel or nearly so whereas Justicia from the OW, where hummingbirds do not occur, lack this arrangement. Insect pollinated Justicia from both hemispheres tend to have highly modified anthers with expanded connective tissue, often with spur-like structures and varying degrees of super-positioning of the thecae. This hypothesis will be tested using morphometric analyses on androecial traits and ancestral states will be reconstructed to elucidate evolutionary transitions in characters likely important in pollination syndrome transitions.

1 - Rancho Santa Ana Botanic Garden, 1500 North College Ave., Claremont, CA, 91711, USA
2 - Rancho Santa Ana Botanic Garden, Department Of Botany, 1500 N. College Avenue, Claremont, CA, 91711, USA

Keywords:
Acanthaceae
Justicia
anther 
plant-pollinator interactions.

Presentation Type: Oral Paper:Papers for Sections
Session: 49
Location: Salon 4/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 1:30 PM
Number: 49001
Abstract ID:1326
Candidate for Awards:George R. Cooley Award