8. Ikrno 41 



considered to take place, and then we have to deal with "altemaU*" 

 instead of ** blending inheritance." It will hi* socn howc'Vrr from what 

 was statc<l above that we are unabK* ju* yrt t<» prove the <)ccurrence 

 of either the one or the other kind of inheriUince. We may alm» here 

 remark that so long as any one, wishing to prove the Hegregation of the 

 allelomorphic characters under considenition, takes plants with exstipu- 

 latc leaves for the standanl, or to boiTow the wonl of Nilsson-Khle, for 

 the "analyser*," he would never be able t^o arrive at a definit<^; con- 

 clusion, owing to the j)ossibility that plants which w(»re at first provided 

 with exstipidat-e leaves only might later devel(>p some stipulate ones. 

 If, on the contrary, we could find in t\ even one plant with all its leaves 

 provided with stipules like the one parent S. gracUistyla it would be 

 possible t^ reach sjifer conclusions ;is to the occurrence of segregation 

 of the allelomorphs under consideration. But not even one single such 

 plant has been obtAined till now. Probably the problem will not be 

 definitely sohtnl without breeding exiK'riments conducted on a far larger 

 scale than wjvs possible for the present author. In short, my experiments 

 .have not been able toprovi* the segregation of the characters "stipulate" 

 and " exstipulate." 



{d) Colour of Stigma. 



In S. multinervis the stigma is bright scarlet, while in S. gracilistijla 

 it is green. In F, plants it is scarlet as in the former. In F^ the 

 segregation of the two opposite characters is quite evident. Thus we 

 have 115 and 16 plants with scarlet and green stigmas respectively, 

 while 7 plants have greenish-red stigmas. If we add those with scarlet 

 and greenish-red stigmas together, we have 122 red and 16 gi-een, i.e. 

 almost 8 red : 1 gi-een. The segregation of allelomorphic charactei-s 

 * red" and "green" is thus clear, but as in other characters hitherto 

 enumerated the usual Mendelian ratio cannot be detected. 



(e) Character of Catkins. 



In S. gracilistyla the catkin, either male or female, is long and 

 broadly cylindrical, and very densely covered with long gray hairs 

 (Plate I, fig. 1, J* — J), whereas in S. multinervis it is much shorter 

 and narrower, and very sparingly hairy (Plate I, fig. 2, J" — J). The 

 chief difference between the catkins of these two species lies thus in 

 the degree of hairiness : in the one they are densely hairy, while in the 

 other they are sparingly so. The distinction between the two in this 



. ^ Lund* Universitets Arsskri/t, N.F., Afd. 2, Bd vii. 1911, p. 18. 



