XIV.—A Comparison of the Minute Structure of Plant Hybrids with that of their Parents, and its Bearing on Biological Problems

Short synopses of my earlier results were given in the Gardeners' Chronicle for April and July 1890. Until after the publication of these I was not aware that some advance had already been made in the direction indicated, and my best thanks are due to Dr Masters for calling my attention to one or two publication's on the subject. In 1831 Professor J. S. Henslow compared a hybrid Digitalis with its parents in a wonderfully minute way, when we consider the degree to which histology had advanced in his time. He demonstrated that in the size and shape of the hairs and other structures, the hybrid was intermediate between its parents. Wichura and Kerner have proved that the same is true of Willows and Pulmonarias respectively.