102 JOUENAL OF THE ROYAL HORTICULTURAL SOCIETY. 
THE FERTILISATION OF FLOWERS BY INSECTS AND 
OTHER AGENCIES. 
Lecture delivered at Chiswick. 
By Rev. Prof. G. Henslow, M.A., Y.M.H., &c. 
• [June 28, 1899.] 
Eaely Knowledge of Plant Sexes. — The belief in the sexes of 
plants was held by the ancients. Thus Pliny, writing in the first century 
of our era, quoting from Theophrastus of the fourth century b.c, says : — 
" The more diHgent inquirers into the operations of Nature state that all 
trees, or rather all plants, belong to either one sex or the other ; one 
which manifests itself in no tree more than in the Palm." * 
Besides the Date, here alluded to by Pliny, the Persians fertilised the 
Terebinth tree ; the natives of Chios, the Mastick ; those of Sicily, the 
Pistacia-nut tree, but not the Fig, for " caprification " only ripened it. 
They nevertheless held fanciful notions about plants, frequently calling 
one the male and another the female, with no real reason whatever ; in fact, 
in certain plants now known to be dioecious these terms were actually 
reversed. This practice was carried down all through the middle ages even 
to the eighteenth century, as by Tournefort. The male was sometimes 
noted as having larger leaves and flowers, the female more dissected 
leaves and smaller flowers, f 
Sir Thomas Millington, Savilian Professor at Oxford, is credited with 
being the first re-discoverer of the doctrine of sexes in the seventeenth 
century. Linnaeus, in his " Dissertation on the Sexes of Plants," j: sa;ys : — 
Dr. Grew, in his ' Anatomy of Plants,' relates that in a conversation on 
the nature of the antherse of flowers Sir Thomas Millington hinted to 
him that those parts might probably be analogous to the male organs of 
animals, and serve for the impregnation of the fruit. Grew approved of 
the idea and pursued it. This is all the account of the matter." § 
Though Linnaeus most distinctly proves the basis of his classification 
on the sexual system to be sound, yet the question was by no means 
settled even in the middle of this century. Investigation by the micro- 
scope raised fresh difficulties, for Schleiden maintained that the embryo 
was formed within the pollen-tube, and it was not until Henfrey and others 
proved conclusively that he was wrong, that the matter was thoroughly 
cleared up. Lastly, it may be added that botanists have now known for 
some years that the pollen-tube contains two " antherozoidal " nuclei, and 
that while one fertilised the germ-cell or nucleus in the embryo-sac, it was 
not known what became of the other. M. Guignard has now explained 
what takes place. Both the pollenic nuclei enter the embryo-sac, and 
* Nat. Hist. bk. xiii., ch. 7. 
t TJie Compleat Herbal, a.d. 1719. Such were the so-called male and female 
PiEonies. 
X Translated by Jas. Ed. Smith, F.R.S., 1786, p. 7. 
§ The note which contains this was probably added by the translator, J. E. Smith. 
