The UNC Plant Information Center's (PIC) "Ask the Expert" module is a question-answering system that allows PIC web site visitors to communicate with botanical experts at the North Carolina Botanical Garden. The objectives of this study were to test users' interactions with the "Ask the Expert" prototype while they sought answers to plant-specific questions and to measure users' satisfaction with specific aspects of the interface. A usability study was conducted with nine members of the PIC Advisory Panel using a web-based test instrument. The results show that participants' reactions to the "Ask the Expert" prototype were positive, especially with respect to its flexibility, ease of use, and the attractiveness of its interface. However, the study did identify some areas where the usability of the application can be improved, particularly with regard to clarifying the details of the multi-step process for submitting a question.