In order to name and classify a plant they see, children use their existing mental models to provide the plant with a name and classification. In this study, pupils of a range of ages (4,8,11 and 14 years old) were presented with preserved specimens of six different plants (strictly, five plants and a fungus) and asked a series of questions about them. The results indicated that pupils of all ages mainly recognize and use anatomical features when naming the plants and explaining why they are what they are. However, older pupils are more likely to also use habitat features. For both girls and boys, home and direct observation are more important as sources of knowledge than school, TV, videos, CD-ROMs or books, though, TV, videos, CD-ROMs and books seem more important for boys than for girls. As pupils age, their reasons for grouping plants become more complicated: in addition to relying on shared anatomical and habitat features, they begin to show evidence of a knowledge of taxonomy and use this knowledge to group plants. Contains 11 references and 9 tables. (Author)