Traditional taxonomic literature can provide a wealth ofdata, but access to that data is limited by its free-text format. Taxonomic treatments such as the Flora of North America (FNA Editorial Committee 1993) consist of terse descriptions of the characters used to identify taxa, such as: “…Leaves usually alternate or opposite, sometimes in basal rosettes, rarely in whorls; rarely stipulate, usually petiolate, sometimes sessile…” Converting taxonomic descriptions to computer-readable format makes them available for automatic retrieval and large-scale analyses. Ontologies such as the Plant Ontology (PO) play a central role in automatic annotation, by providing semantic meaning for the words in a description. We used automated and manual methods to map terms from the Categorical Glossary for the Flora of North America Project (http://128.2.21.109/fmi/xsl/FNA/home.xsl) to the PO.