load themselves with pollen in an ordinary tulip-bed and fly
over to his imperfect flowers. After they were gone, he
observed that they had left on the stigmas a quantity of pollen
sufficient for fertilisation, and these tulips did in fact produce
seed. Miller also kept some female plants of spinach apart
from the male, and found that they bore large seeds without
embryos.
Professor Gleditsch, Director of the Botanic Garden in Berlin, described in the same year ('Histoire de l'Academic royale des sciences et des lettres' for the year 1749, published in 1751 at Berlin), an experiment on the artificial fertilisation of Palma dactylifera folio flabelliformi, which was no doubt our Chamaerops humilis, since he says himself in page 105 that it was Linnaeus' Chamaerops, and Koelreuter speaks of the plant in his report by that name. This treatise, in point of scientific tone and learned handling of the question, is the best that appeared between the time of Camerarius and that of Koelreuter. We learn from the introduction, that in the year 1749 there were few who doubted the existence of sexuality in plants. The author says that he has endeavoured to attain to perfect conviction on the point by many years' experiments with plants of the most various kinds. Of late years he had chiefly selected dioecious plants for investigation, Ceratonia, Terebinthus, Lentiscus, and the species of date-palm which is commonly called Chamaerops. After relating the formation of fertile seeds in Terebinth and the mastic-tree produced by artificial pollination, he turns to Chamaerops, of which species Prince Eugene had repeatedly caused specimens of considerable size to be brought over from Africa; a specimen cost as much as a hundred pistoles; but they died without flowering. 'Our palm in Berlin,' he continues, 'is a female, and may be eighty years old; the gardener asserts that it has never borne fruit, and I have myself never seen fertile seeds on it during fifteen years.' As there was no male tree of the kind in Berlin, Gleditsch procured some pollen from the garden of Caspar Bose
