David Hershey (1999), a leading US authority on teaching about plants, noted that "Nonscientists are often fascinated by studies of unusual plants such as Rafflesia [pricei], the world's largest flower, and carnivorous plants, or germination of thousand-year-old lotus seeds. The value of those [research] studies is not diminished because people make money writing about them in popular books or producing PBS shows about them. Rather, botany gets some much needed publicity." In a follow-up effort to explain scientifically what we have dubbed the 'marquee plant' phenomenon, and to derive some implications for improving public understanding of plants and botanical learning, we analyzed the visual characteristics of several unusual plants commonly found at botanic gardens, using selected vision science metrics. The six plants we studied were Agave americana (century plant), Amorphophallus titanum (titan arum), Araucaria araucana (monkey puzzle tree), Musa sapientum (grocer's banana), Lithops lithops (living stones), and Victoria amazonica (giant Amazon water lily). We also used Krippendorfian content analysis of written accounts of botanic garden visitors' responses to these plants as a cross-check when drawing our conclusions. Results of our study indicate, for example, that the public attention and curiosity aroused by these marquee plants may be explained, at least in part, by using marquee-plant-specific visiometric data and Solso's INFOPRO human visual information processing model. We then used our findings to propose a visual-cognition-based 'Limiting Cases learning strategy' which can be used to anticipate which plants may function as marquee plants, and to explain how they might serve as springboards for botanical learning about findamental plant science concepts and principles--both in informal and academic botanical educational settings.

Key words: botanical education, Limiting Cases learning strategy, marquee plants, public understanding of plants, visual cognition