Would like to cite WO’s case of bees perforating white but not blue monkshood (Aconitum napellus) in his next book [Cross and self-fertilisation, pp. 427–8]. Believes it is probably sterile if insects are excluded.

Recounts his observations on the different ways bees perforate flowers of white and blue varieties of monkshood. [See Cross and self-fertilisation, p 428.]