A new computer program for the clustering of ecological data is presented. It is different from the programs which are commonly used in two aspects: Firstly, the program is interactive to a large extent, which implies that a priori decisions are limited. Secondly, the results of the clustering can be evaluated in terms of environmental data for the sites. The program provides several options to construct a species by site table. It is concluded that interactive clustering is preferable when data properties in terms of the (dis)sirailarity measure or clustering algorithm are less familiar to the user of the program.