THE SEXES OF FLOWERING PLANTS 47 



world as a simple chain or scale. They were also 

 wrong in assuming 1 that all the links or steps still exist. 

 We can now see that vast numbers are irrecoverably 

 gone. It is a safe prophecy that the filiation of species 

 will never be grasped by the intelligence of man except 

 in outline, and even an outline which shall truly express 

 the genetic relations of many chief types is unattainable 



at present. 



The Sexes of Flowering Plants. 



As soon as men began to raise plants in gardens, or 

 even earlier, they must have remarked that plants 

 produce seeds, and that seeds develop into new plants. 

 The Greeks (Empedocles, Aristotle, Theophrastus) 

 recognised that the seed of the plant answers to the 

 egg of the animal, which is substantially though not 

 literally true. None of the three understood that a 

 process of fertilisation always, or almost always, pre- 

 cedes the production of seed. Had the date-palm, 

 whose sexes are separate, and which has been artificially 

 fertilised from time immemorial, been capable of cultiva- 

 tion in Greece, Aristotle would not have said that plants 

 have no sexes, and do not require to be fertilised. His 

 pupil, Theophrastus, knew only by hearsay of the male 

 and female date-palms, and affirmed that both bear 

 fruit. Pliny, three hundred years later, called pollen 

 the fertilising substance, and gave it as the opinion of 

 the most competent observers that all plants are of two 

 sexes. The revivers of botany paid no attention to 

 pollen or the function of the flower ; it is more sur- 

 prising that in the following century Malpighi, who had 

 diligently studied the development of the plant-embryo, 

 should give so superficial an account of the stamen and 

 its pollen. About the same time Grew and Millington 

 expressed their conviction that " the attire " (anthers) 



