1913] Goodspeed: Nicotiana Hybrids 179 



peculiarities is possible. A plant that is making seed cannot 

 produce better than stunted, functionless flowers among the 

 maturing seed capsules yet if the young seed capsules are re- 

 moved as they form, the secondary flower buds will produce nor- 

 mal flowers almost indefinitely. It is a repetition of the "top- 

 ping" and "suckering" under different conditions to accomplish 

 the same type of ends and a rather perfect set of cause and 

 effect phenomena. 



With these facts in mind it Avas a surprise to find, in the 

 case of the hybrids between N. sylvestris and N. Tabacum- 

 varieties, that on an inflorescence, and usually with all old flowers 

 fallen and the stems bare, these same late flowers were as thor- 

 oughly stunted as in the case of the parents. Five to eight 

 flowers on these older hybrid 'infloresences, on which no seed has 

 been formed, often stand on the naked branches and are as 

 abnormal, stunted and poorly formed as in the parent plants. 

 In other words though no subtraction takes place from later 

 flowers in favor of maturing seed capsules in these hybrids, still 

 the phenomenon of reduced reproductive parts is apparent in 

 these later flowers. Here Ave have a '"physiological unit-char- 

 acter" dependent upon metabolic activities and one which is 

 seemingly an indivisible unit connected with cause and effect 

 relations common to all plants which, nevertheless, is so split 

 up in crossing that the effect is inherited when the cause is absent. 

 Undoubtedly the real situation here is too obscure to offer more 

 than an interesting field for speculation but the fact seems of 

 sufficient interest to be noted. In the parent plants it is possible 

 to eliminate the effect (reduction in size and vigor of older 

 flowers) by eliminating the cause (removing young seed cap- 

 sules as they form) — in the hybrid individuals the cause is self, 

 automatically, naturally removed but the effect is present un- 

 changed. 



An explanation of this phenomenon, which has hardly more 

 than the minimum of experimental e\adence as its basis, should, 

 however, be mentioned here. It is just conceivable that the 

 factor for the production of abnormally reproductive organs 

 represents a dominant character in these hybrids commonly 

 considered to be completely sterile and wliidi normally are 



