CHOROLOGY, COLLECTION DATES, AND TAXONOMIC RESPONSIBILITY

Summary Taxonomists generally recognize the value of collection dates in planning biosystematic research but do not always appreciate their usefulness in documenting migrations and introductions. A survey of several journals shows that many taxonomists fail to include collection dates in monographs and other taxonomic treatises. Correlation of collection dates for a particular taxon with dates of general botanical collecting in a particular locality has been used to document an eastward migration of Dyssodia tenuiloba (DC) Rob. in Texas and the introduction of Thelypteris dentata (Forssk.) E. St. John into the New World.