ORGANS AND SYSTEMS OF ORGANS. 165 



It would be useless as well as nearlj^ impossible to change our 

 present terminology; for example, the expressions stamen-leaf, pis- 

 til-leaf, etc. It is, however, necessary to call attention to what I 

 believe to be erroneous tendencies. 



Palaeontology cannot produce any evidence to show that phan- 

 erogams did not always possess vegetative as well as reproductive 

 organs. There is no scientific basis for the assumption that our 

 present phanerogams were preceded by ancestral forms with only 

 vegetative organs.' 



C. The Complex Organ : Shoot. 



The relation between caulome and phyllome leads to the follow- 

 ing discussion. The leaf-bearing caulome is called a shoot, the 

 young shoot is called a l)ud. The stem-portion between two suc- 

 cessive leaves, or, in case more that one leaf occurs in the same hori- 

 zontal plane, between two successive whorls of leaves, is called the 

 internode. The ^io^Z^ ("joint " or "knot") is that portion of the 

 caulome on which the leaf is borne or inserted ; it is often somewhat 

 enlarged and differently colored. The entire habit of a plant de- 

 pends in a high degree upon the length and thickness of the inter- 

 nodes. In the youngest stage the leaves are very closely crowded 



' These observations by the author may be of value iu cicatiug criiical thought, 

 but they cannot be considered as arguments against the theory of descent (evolu- 

 tion). To those transition-forms occurring among tlie GompositcB might be added 

 numerous other examples'; especially interesting is the case of Nymphcm tuberosa, 

 in which the transition from green leaf through jietal to perfect stamen is some- 

 times almost complete. It must, however, be borne in mind that such transitions 

 are themselves the products oi phylogenesis, and not of ontogenesis. To bring about 

 permanent states of transition, as, for example, the conversion of a formative cell- 

 gidup into a stamen rather than a leaf, requires at least millions of years, as the 

 geologic record shows. In comparing a leaf with a stamen or with awy other 

 organ it must be remembered that both are the products of evolution, and that the 

 present dissimilarities did not exist originally. 



To my knowledge no scientist has ever denied that phanerogams as sr.ch did 

 not always possess both vegetative and reproductive organs ; they would not be 

 phanerogams if they did not. The problem is to trace the evolution of the various 

 organs, and to show how they are connected throughout the various groups of the 

 vegetable kingdom. 



The pal aeon tologic record as far as it goes bears out the facts of evolution. 

 Every scientist admits that the geologic record is of necessity broken, but even 

 these gaps are becoming gradually less apparent. — Tbans. 



