Development of Teaching Materials for Field Identification of Plants & Analysis of Their Effectiveness in Science Education

THERE exists a variety of methods for identification of plants as described in detail elsewhere (Tilling 1984). Among those methods two major approaches emerge, one utilizing dichotomous keys and the other synoptical keys (Kanai 1962, 1989; Ono & Kojima 1979). In general, the former corresponds to single-access keys, the latter multi-access keys. Traditionally, dichotomous keys have been used for plant identification. Most books on plant taxonomy that have been published so far utilize dichotomous keys. With this type of key readers are asked to select between two choices in a predetermined series of steps. This procedure is repeated until the name of a specimen is unambiguously identified. This approach is quite useful when a specimen is presented with many characters one can use for its identification. Synoptical keys, on the other hand, utilize a set of characters a specimen on hand actually possesses (Kanai 1978a; Pankhurst 1978; Ono & Kojima 1979). One can observe any number of characters among the keys in an arbitrary order for identification; hence this method is easy to adopt even if some of the characters are missing in the specimen and the user’s knowledge cannot make up for the missing information. Still, synoptical keys are not as widely used as dichotomous keys because the space required for all the characters used for synoptical keys is much larger than that for dichotomous keys (Kanai 1962, 1978b). The author believes, however, that the application of computers and electronic data storage would easily solve this space problem. Plant names and their characters are stored in a two-dimensional matrix, a data structure readily created by relatively simple computer programs. The content of the matrix is easily edited, and retrieval of information for a specific plant is straightforward. A large selection of