Russell, R.B., C.R. White, C.K. McMullen. 2004. Meiotic chromosome counts of Alternanthera (Amaranthaceae) species from the Galápagos Islands.

Poster Abstract: Fourteen species of Alternanthera Forssk. (Amaranthaceae) inhabit the Galápagos Islands. Six species are endemic, with one of these, A. filifolia comprising seven subspecies. Of the remaining eight species, five are native and three are introduced. The majority of these species are thought to have originated in the Andean region of South America and arrived in Galápagos via long-distance dispersal by birds. Members range in habit from low-growing subshrubs to small trees, and occupy both the arid lowlands and the moist uplands. The endemic members of this genus are significant because they demonstrate one of the better examples of adaptive radiation among Galápagos plants. This study is attempting to document haploid chromosome numbers for these plants by observing pollen mother cells during meiosis. Such information may prove useful in defining and identifying members of Alternanthera. It may also be helpful in determining the mainland origin of the genus and determining its evolutionary history (phylogeny). Bud material for chromosome counts were obtained from plants growing in the JMU greenhouse. Standard techniques for staining and studying plant chromosomes are being employed.