384 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
sequence of the discovery of individual phenomena in plants as a 
whole. 
In following the evolution and change in aspect of our problem we 
shall often find it best to keep a few relatively great names prominent. 
This will serve in the first place to make the story more vivid and intel- 
ligible. It will at the same time often come nearer the essential 
truth, for in each great forward step some one worker has usually 
been the dominating leader. 
I.—_THE DISCOVERY THAT POLLINATION IS A PREREQUISITE TO SEED 
FORMATION, 750 B. C. TO A. D. 1849. 
The first discoveries pointing to the existence of sex in plants 
were evidently made very early in human history by peoples culti- 
vating unisexual plants for food. The existence of fertile and sterile 
trees of the date palm was known to the peoples of Egypt and 
Mesopotamia from the earliest times. Records of the cultivation of 
these trees and of artificial pollination have come down to us on bas- 
reliefs from before 700 B. C., found in the palace of Sargon at Khorsa- 
bad (Haupt and Toy, 1899).1. The Assyrians, it is said, commonly 
referred to the two date trees as male and female (Rawlinson, 1866). 
The Greeks, in spite of their peculiarly keen interest in natural 
phenomena, failed to offer any definite interpretation of this well- 
known fact concerning the date palm. Aristotle and Theophrastus 
report the fact, gained apparently from the agriculturists and herb 
gatherers, that some trees of the date, fig, and terebinth bear no 
fruit themselves, but in some way aid the fertile tree in perfecting 
its fruit. But without recording a single crucial experiment on the 
matter Theophrastus concludes that this can not be a real sexuality, 
since this phenomenon is found in so few plants. 
In this uncertain state the knowledge of sexuality in plants was 
destined to rest for 20 centuries, waiting for the experimental 
genius of Camerarius to give a conclusive answer to the question 
raised by the Assyrian and Greek gardeners and answered wrongly 
by Theophrastus. The English physician Grew (1676) did, it is 
true, accept and expand the suggestion of Sir Thomas Millington 
that the stamens serve as the male organs of the plant. Thus Grew 
concludes (p. 173) that when the anther opens, the ‘‘globulets in the 
thecz act as vegetable sperm which falls upon the seed case or womb 
and touches it with prolific virtue.” But this guess, though it 
proved correct in the main point, was still a guess and not supported 
by any critical evidence so far as recorded by Grew. ‘The only 
adequate evidence that could be obtained on this question, while 
microscopes and technique were so imperfect, was experimental 
evidence. This kind of proof was first given some 20 years after 
1 Dates herein indicate publication of discovery. See bibliography appended to present article in 
Science, Feb. 27, 1914. 
