Remarks on the influence of pollen of one species or variety on the seed and fruit of another while still attached to the female plant. Refers to a remarkable case previously given by D. Beaton and asks whether Beaton will repeat the details.

[CD’s letter is followed by notes by D. Beaton in which he answers CD’s question, dissociating himself from some of his remarks, and in particular denying C. F. v. Gärtner’s claim that colour of one variety of pea can be changed by the direct action of the pollen of a different variety.]

Answers D. Beaton’s criticism of Gärtner’s work, defending his results in crossing experiments and vindicating the memory of "one of the most laborious lovers of truth who ever lived".

Reports the observations of Hermann Crüger and John Scott that fruit is set by orchids whose flowers never open and that pollen-tubes are emitted from pollen-masses still in their proper position. These cases convince CD that in Orchids he underestimated the power of tropical orchids to produce seed without insect aid but he is not shaken in his belief that the structure of the flowers is mainly related to insect agency.