Abstract Detail

Systematics Section

Tripp, Erin [1], Mcdade, Lucinda [2], Isa, Siti Fatimah [3], Darbyshire, Iain [1].

Physacanthus (Acanthaceae): a heteroplasmic, intergeneric, interlineage hybrid?

Taxonomic affinities of the genus Physacanthus (Acanthaceae) have been in question for well over a century. Different authors have classified the genus into one of two distantly related lineages in the family: tribes Acantheae or Ruellieae. Morphological features (e.g., presence/absence of cystoliths, monothecous vs. bithecous anthers, open or ascending cochlear vs. contort corolla aestivation) support the phylogenetic distinctiveness of Acantheae and Ruellieae, and analyses of molecular data indicate that the two clades are not sister taxa. Thus, it is curious that researchers have struggled to classify this genus based on its phenotype. To ascertain which lineage Physacanthus is allied to, we re-evaluated morphology of the genus and generated nuclear and chloroplast sequence data for 18 accessions representing all three species inthe genus. Unexpectedly, in multiple instances, cloning led to the retrieval of both Acantheae- and Ruellieae-like chloroplast genotypes from single accessions of Physacanthus, indicating that plants are heteroplasmic. Although our limited nuclear data (here, only ITS) do not support the hybrid hypothesis, morphology does: species of Physacanthus possess some traits characteristic of Acantheae, but others characteristic of Ruellieae.

Broader Impacts:

Related Links:
http://www.tolweb.org/acanthaceae
http://www.rsabg.org/acanthaceae
http://www.tolweb.org/acanthaceae
http://www.rsabg.org/acanthaceae

1 - Royal Botanic Gardens, Kew, Herbarium, Tw9 3ab, Richmond, Surrey, UK
2 - Rancho Santa Ana Botanic Garden, Department Of Botany, 1500 N. College Avenue, Claremont, CA, 91711, USA
3 - Rancho Santa Ana Botanic Garden, 1500 N College Ave, Claremont, CA, 91711, USA

Keywords:
hybrid
systematics
intergeneric
heteroplasmy
evolution.

Presentation Type: Oral Paper:Papers for Sections
Session: 36
Location: Lindell B/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 3:00 PM
Number: 36007
Abstract ID:183