THE MOlll'HOLOGICAL COMPOSITION OF PLANTS. 37 43 



11:16 observation of these and some analogous monstrosities, 

 raising the suspicion that the distinction between foliar 

 organs and axial organs is not absolute, led me to examine 

 into the matter ; and the result has been the deepening o! 

 this suspicion into a conviction. Part of the evidence is given 

 in Appendix A 



Some time after having reached this conviction, I found on 

 looking into the Kterature of the subject, that analogous ir- 

 regularities have suggested to other observers, beliefs similarly 

 at variance with the current morphological creed. Diffi- 

 culties in satisfactorily dehning these two elements, have 

 served to shake this creed in some minds. To others, 

 the strange leaf-like developments which axes undergo in 

 eertain plants, have afforded reasons for doubting the 

 constancy of this distinction which vegetal morphologists 

 , usually draw. And those not otherwise rendered sceptical, 

 have been made to hesitate by such cases as that of the 

 Nepaul-barley ; in which the glume, a foliar organ, becomes 

 developed into an axis, and bears flowers. In his essay — 

 " Vegetable Morphology : its History and Present Condi- 

 tion," * whence I have already quoted, Dr Masters indicates 

 sundry of the grounds for thinking, that there is no impassable 

 demarcation between leaf and stem. Among other difficult- 

 ies which meet us if we assume that the distinction is abso- 

 lute, he asks — " What shall we say to cases such as those 

 afforded by the leaves of Guarea and Trkhilia, where the 

 leaves after a time assume the condition of branches and de- 

 velop young leaflets from their free extremities, a process lesa 

 perfectly seen in some of the pinnate-leaved kinds of Berheris 

 or Mahonia, to be found iu almost every shrubbery ? " 



A class of facts on which it will be desirable for us nere to 

 dwell a moment, before proceeding to deal with the matter 

 deductively, is presented by the Cactaceae. In this remark- 

 able group of plants, deviating in such varied ways from the 

 ordinary phsenogamic type, we find many highly instructive 



• See Brilish and Foreign Medico-Chirurgical Review for .Tanuary, 1864. 



