Nectar spur evolution in the Mexican lobelias (Campanulaceae: Lobelioideae)

Margaret M. Koopman, Tina J. Ayers

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Phylogenetic studies are often hampered by the independent evolution of characters that may potentially obscure relationships. The adaptive significance of the nectar spur and its evolution within the Mexican lobeliads (Campanulaceae) is considered here. The taxonomic delimitations of Heterotoma from the Mexican species within the genera Lobelia and Calcaratolobelia were tested. Independent molecular data were gathered to determine whether the Mexican spurred lobeliads should be treated as distinct genera. The internal transcribed spacer (ITS) region from 18-26S nuclear rDNA and chloroplast DNA from the 3′ trnK intron were sequenced from 14 representative species. Our data suggest that Heterotoma, as originally conceived, is a good evolutionary unit within Lobelia and that the presence of a nectar spur is an important morphological character that can be used in defining phylogenetic position. This study also suggests that morphological changes associated with hummingbird pollination have evolved more than once in the Mexican lobeliads, from small blue-flowered, insect-pollinated relatives.

Original languageEnglish (US)
Pages (from-to)558-562
Number of pages5
JournalAmerican Journal of Botany
Volume92
Issue number3
DOIs
StatePublished - Mar 2005

    Fingerprint

Keywords

  • 3′ trnK intron
  • Heterotoma
  • ITS
  • Lobelia
  • Nectar spur
  • Pollination
  • Systematics

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Plant Science

Cite this