Abstract Detail

Systematics Section / ASPT

Li, Jianhua [1].

Molecular phylogeny and biogeography of Catalpa (Bignoniaceae), an eastern Asian-eastern North American disjunct genus.

Sequences of internal transcribed spacer region of nuclear ribosomal DNA were used to estimate phylogenetic relationships of Catalpa (Bignoniaceae). Kigelia and Tecoma were included for rooting purposes. Parsimony analyses of the sequences recognized the sister relationship of Chilopsis linearis and Catalpa, and the monophyly of Catalpa and sections Macrocatalpa and Catalpa. Catalpa ovata formed a clade with North American species, C. speciosa and C. bignonioides, while the other eastern Asian species formed a clade where C. duclouxii was sister to the clade of C. bungei and C. fargesii. Section Catalpa diverged from its xerophytic ancestors in response to the shift to mesophytic habitats. The production of the foliar nectar and related insect-plant mutualism, and the increase of inflorescence size are derived features for increasing the fruit set and ultimately the reproduction. The dispersal vicariance analyses suggest that modern distribution of North American species of Catalpa is the result of a recent dispersal of their ancestral populations from eastern Asia. The diversification of tropical species of Catalpa probably occurred in the Late Paleocene.

1 - Harvard University, Arnold Arboretum, 22 Divinity Avenue, Cambridge, Massachusetts, 02138, USA

Keywords:
phylogeny
biogeography
Catalpa
Bignoniaceae
eastern Asian and North American disjunct
West Indies
nrDNA ITS sequences.

Presentation Type: Paper
Session: 28-6
Location: Cottonwood A (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 9:15 AM
Abstract ID:145