The Digital Flora of Texas project is a collaborative research effort that relies on botanical research centers in Texas to create and maintain digital library collections on the flora of Texas. The project focuses on developing web-accessible collections for botanists and botanically-interested nonspecialists. The Herbarium Specimen Browser (HSB) is the main portal to the collections of the Digital Flora of Texas. The HSB allows examination of the collections through several types of interactive information visualizations: a hierarchical taxonomic browser, specimen distribution and density maps, and stackable bar graphs of temporal specimen data. The interactive information visualization tools of the HSB are designed to help users extract as much information from the data as possible while minimizing the associated learning cost and complexity of these tools.