Skip to main content

Taxonomy of Exochaenium and Lagenias: Two Resurrected Genera of Tribe Exaceae (Gentianaceae)

Buy Article:

$15.00 plus tax (Refund Policy)


Morphological and molecular evidence has recently revealed the paraphyly of Sebaea (Gentianaceae: Exaceae), and support the establishment of three genera corresponding to highly supported clades. Consequently, the reinstatement of both Exochaenium and Lagenias as genera segregated from Sebaea is proposed here. Exochaenium consists of 22 species distributed in tropical continental Africa that are characterized by papillate stigmas and cubical seeds with star-shaped testa cells. Lagenias is a monotypic genus endemic to the Western Cape Province of South Africa, which differs from Exochaenium and Sebaea by its medifixed anthers, the insertion of the filaments at the base of the corolla tube, and cubical seeds with polygonal testa cells. The synapomorphies of Sebaea s. s. are the presence of secondary stigmas along the style and seeds with rectangular testa cells arranged in parallel rows. Differences with the other genera of tribe Exaceae (Exacum, Gentianothamnus, Klackenbergia, Ornichia, and Tachiadenus) are discussed. In addition, diagnostic characters as well as keys to the genera of the tribe and species of Exochaenium are provided. To account for the new circumscription of Exochaenium, 12 new combinations are also published here ( Exochaenium alatum, E. caudatum, E. clavatum, E. dimidiatum, E. fernandesianum, E. hockii, E. lineariforme, E. macropterum, E. oliganthum, E. perparvum, E. rotundifolium, and E. wildemanianum ).
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
No Metrics

Keywords: Africa; Belmontia; Parrasia; Sebaea; classification; floral morphology

Document Type: Research Article

Publication date: 01 January 2012

More about this publication?
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more