PLANT HYBRIDIZATION BEFORE MENDEL 71 



existence of true sex in plants, "but their number is very small, 

 and their arguments do not appear to merit any response." 



"Leaving all these disputes to one side," he continues, "I have only 

 been interested in acquiring a full proof of this theory ; and to this end, 

 for several years, I have made experiments on plants of every sort, and 

 I have had the pleasure of seeing the truth discover itself to my re- 

 searches, and especially in later years, with perennial plants, trees of the 

 same natural species (the sexualists call them vulgarly dioecious), of 

 which one carries the male flowers, while the other, its companion, which 

 is quite a different one, carries only the female flowers." (5a, p. 103.) 



Of these he mentions, (p. 104) the genera Ceratonia, Pistacia, 

 Terebinthus and Lentiscus, and "cette espece de Palmier dactyli- 

 fere qu'on nomme vulgairement Chamaerops, Chameriphesy 



In the garden of the Academy of Sciences in Berlin, he com- 

 ments, the difference in sex in the flowers of trees had long been 

 noticed, the gardener himself having remarked it for more than 

 twenty years. The latter was, however, unable to discern the cause 

 of sterility in the plants. The simplicity of mind obtaining in re- 

 gard to the matter at the time is evidenced by Gleditsch's remark, 

 that the gardener was greatly surprised at the appearance of the 

 perfect fruits of the terebinth {Pistacia terebinthus), because he 

 had not thought of this, that the simple sprinkling of the powder 

 of the anthers was sufficient to effect its production. His surprise 

 doubled especially, when, from these fruits, either planted of 

 themselves in the ground or planted expressly with care, he saw 

 arise, a little afterwards, the finest plants in the world, (p. 104.) 



The attempt is mentioned of Prince Eugene of Austria, during 

 the last years of his life, to secure the artificial pollination of the 

 palm, a matter of which he had read descriptions. To this end, 

 he had palm trees of the different sexes and of considerable size, 

 sent to his garden at Vienna, but the palms perished in the space 

 of a year, without flowering. 



The palm at Berlin upon which Gleditsch determined for his 

 experiments, was a pistillate tree, which was, as he says, possibly 

 more than eighty years old, "and certainly the largest of all those 

 of its species which are found today in the gardens of Germany." 

 According to the testimony of a man said to be of note, and then 

 in his sixty-sixth year, the tree in question was formerly in the 

 Royal Garden at Berlin, and had been seen by the person referred 

 to in its earliest days. During this entire time the tree had borne 



