Occurrence of Domatia as a systematic character

In our Bulletin no 20, pp. 1272-1273, Dr. M. Jacobs made some notes on the nature and occurrence of domatia. His full paper has now appeared (Proc. Kon. Akad. Wet. A’dam C 69, 1966, 275-316, repr. 1-44) and this means to be a great step forward in the study of these peculiar structures, which are diverse in structure, though still obviously homologous, and not due to the action of acari. Their function is obscure and may be nil; it is remarkable that they are restricted to ligneous plants and that though occurring in plants of both cold and hot climates, they have not yet been found in plants growing in permanently dry climates. In ’placing' plants, inadequate material in particular, it was in my experience always a great help to me if domatia were present, as they represent an indicator character. This in turn points to their systematical value in specified cases.