TYPICAL FORMS OF PLANT KINGDOM 103 



fertile, and are always arranged in the same order, a whorl 

 of male leaves or stamens, above the corolla, and a whorl of 

 female leaves or carpels, formed at the end of the floral branch. 

 At first sight the mechanism of this transformation is 

 not apparent ; however, in the light of what we already know 

 of the nature of the sexes, it is possible to make a good guess. 

 In the first place sex is not, as we might be tempted to judge 

 from ordinary observation, something absolute. We have seen 

 that the difference between the male and the female cells is 

 essentially a difference of aptitude for nutrition. This difference 

 can be aggravated by an increase or decrease of nutrition in the 

 individuals producing these cells. A simple transplantation 

 often suffices to change Thladianta dubia (Blavet), Trice- 

 nosperma ficifolia, Dioscorea canariensis, and Clematis hilarii 

 (Spegazzini, 1900), from the female to the male sex. The same 

 result has been obtained by cutting off the head of a willow 

 (Salix caprcea, Haacke, 1896). The contrary transformation has 

 been obtained also in willows (Klein, 1896) : Edmond Bordage 

 saw the same thing take place in a papaw on Reunion Island 

 (1898) ; Hariot (1902) and Davaul (1903) announced that this 

 phenomenon is habitually produced in the palms of the oases 

 of Southern Algeria by longitudinally splitting from the centre 

 to the sheath all the leaves of stems two or three years old. 

 Moreover, in a series of the most exact and ingenious 

 experiments, Blaringhem x has obtained the most startling 

 results. Dividing the young female stems of Mercucialis and 

 of Spinach, he saw shoots arise each bearing male and female 

 flowers, and thus he transformed a dioecious plant into a 

 monoecious one. He was able to go even farther, and obtained 

 hermaphrodite flowers by mutilating the stalks of the male 

 hemp. His experiments on Maize also proved the influence of 

 nutrition upon these phenomena. Maize-stalks, as we all know, 

 terminate in a plume of male ears which becomes characterized 

 at an early stage ; later on female ears, enveloped in large 

 bracts, appear at the flower-axil of the stalk, like lateral 

 branches. It may be observed that the male tuft forms at the 

 stage when the young maize-stalk is only growing small roots ; 

 consequently its nutrition is not very active and tachygenesis 

 makes it develop too soon. The female ears, on the contrary, 



1 XXXIX, 124. 



