Submitted to: Botanical Garden Annals Missouri
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2002
Publication Date: N/A
Interpretive Summary: Analyses of morphological and DNA sequence characters are used to infer the relationships of the genus Hymenocallis, which have been highly changeable over the past two centuries. The genera Leptochiton, Ismene, Elisena and Pseudostenomesson have been included with Hymenocallis, lumped together as the genus Ismene, or maintained as distinct genera. Our analyses show that Leptochiton is the most primitive genus in the group and that Hymenocallis and Ismene (including Elisena and Pseudostenomesson) should be treated as distinct genera. Our data thus bring a stable nomenclature and classification to a group of ornamental flower bulbs that have had a confusing taxonomic history.
Technical Abstract: The generic limits of Hymenocallis Salisb. have been variously proposed by different taxonomic workers, often without discussion or data. The genera Leptochiton, Ismene, Elisena and Pseudostenomesson have been included with Hymenocallis, lumped together as the genus Ismene, or maintained as distinct genera. Recent cladistic analysis of plastid and nrDNA for Amaryllidaceae support a distinct tribe Hymenocallideae. Cladistic analyses of morphology, plastid and nuclear ribosomal DNA are presented alone and in combination for the tribe. Leptochiton is sister to the rest of the genera in the tribe in all analyses. While Hymenocallis is always resolved as monophyletic, Ismene is variably paraphyletic or monophyletic. The combined sequence data produces the most resolved and best supported phylogeny, wherein Hymenocallis and Ismene are monophyletic sister genera. These data support an origin for the tribe in the Andes, with vicariant distribution of the largely Meso-American Hymenocallis.