Jamesbondia, a new subgenus of Alternanthera (Gomphrenoideae, Amaranthaceae) from Central America and the Caribbean Islands

Jamesbondia is formally proposed here as a new subgenus of Alternanthera, a large Neotropical genus, with four species [A. costaricensis Kuntze, A. geniculata Urb., A. olivacea Urb., and A. serpyllifolia (Poir.) Urb.], mostly found in Central America and the Caribbean Islands. In a recent phylogeny using internal transcribed spacer (ITS), trnL-F, and rpl16 data and samples of three of the four species listed above, an unpublished genus Jamesbondia was embedded within Alternanthera. The other three species (not A. costaricensis) clustered in a clade with 97% jackknife (JK) support. Here, to determine the position of A. costaricensis within Alternanthera and taxonomically revise the species in subgenus Jamesbondia, we analyzed ITS, trnL-F, and rpl16 data from GenBank accessions for 31 species and our new molecular data for A. costaricensis to reconstruct a phylogenetic tree confirming that A. costaricensis belongs to the Jamesbondia clade (88–97% JK; 0.88–1.0 posterior probability). Alternanthera costaricensis, Telanthera olivacea Urb., and Achyranthes serpyllifolia Poir. were lectotypified, and we document the distribution of A. costaricensis in Mexico for the first time. Insight from nomenclatural notes, taxonomic descriptions, morphological illustrations, distribution, and a key for species of Jamesbondia provided here will be used to propose a new subgeneric classification of Alternanthera.