738 
DUNCAN S. JOHNSON 
that disturb the normal production or course of movement of 
material in the plant. 
The evidence from this study of Piper betel concerning the dis- 
tinction of sexes in the sporophyte, seems to show that the tis- 
sue of the young spike, and often of the individual flower, must 
be hermaphrodite in character. The differentiation of the sexes, 
by separation or by the suppression of one of them, must take 
place at or after the initiation of the rudiments of the parts of the 
flower. This view is in accord with the conclusion gained from 
experimental work on a number of species of angiosperms, as 
well as on certain lower plants. 
BIBLIOGRAPHY 
Blakeslee, a. F. 1906 The differentiation of sex in thallus, gametophyte and 
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