Answering criticism on his proposals for collecting more phenological data in vegetation study, the author argues that 1. Choice of research problems should not be determined by availability of simple methods or measures. 2. Scales for field estimations should be adapted to possibilities for subsequent calculations and use of punch cards. 3. Close cooperation with a mathematician or systems analyst is necessary for a team of ecologists. If this can be achieved, there is a danger of insufficient availability of field data rather than that of stockpiling data that may remain unused. 4. Correct processing of limited data may give misleading results. The most efficient way to check this is the possibility of reference to field notes containing as many observations as possible. 5. Reference is made to various authors recently working on the phenology of plant communities.