Sex Determination 195 



examples. The dioecious Thalictrum, however, behaves 

 differently in cases of parthenogenesis. The progeny 

 are sometimes female, but just as often they are male. 

 This situation deserves further investigation. There 

 is no question but that STRASBURGER'S theory is in- 

 genious, reasonable, and promising. 



A striking bit of work on sex determination was done 

 by CIESIELSKY (14) of Lemberg, who worked with 

 Cannabis saliva, the Indian hemp. When he used pollen 

 fresh from the anthers the progeny were 85 per cent 

 males. When he took pollen from the anthers and 

 allowed it to stand for twelve hours or more before 

 using it the resulting progeny were 92 per cent females. 

 The conclusion is obvious that fresh pollen results in 

 males and stale pollen results in females. This can be 

 combined with STRASBURGER'S idea, for one might 

 expect fresh pollen to show stronger male tendencies 

 than stale pollen. CIESIELSKY'S work deserves to be 

 repeated upon a more extensive scale. 



Probably the most unorthodox behavior of sex is 

 that which was rather recently described in the Papaya 

 (6). A few cases were described in which male Papaya 

 trees had been cut back. The whole head of the tree 

 had been cut off, eliminating all of the male flowers. 

 When new branches put up from the cut trunk they 

 bore in some cases hermaphrodite and in other cases 

 prevailingly female flowers. That sex could be so com- 

 pletely changed by such an operation was incredible. 

 Further examination showed that this result was not 

 always obtained and that in fact there were only a few 

 such cases on record. Most botanists today doubt the 

 validity of this reported behavior. 



