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SCIENCE. 



[N. S. Vol. XXIII. No. 582. 



or apparatus of the function, it by no 

 means follows, as is too often assumed, that 

 moi'phology disappears as such and be- 

 comes merged with physiology. The 

 methods of nature are economical in the 

 extreme, and when she needs a ploughshare, 

 she fashions it from a no longer useful 

 sword, or if a pruning hook be required, 

 she straightway makes it from a spear, 

 without in either case too carefully obliter- 

 ating the signs of former use. By reason 

 of this fact, with changing conditions, the 

 apparatus of obsolete functions is not cast 

 aside and replaced by other apparatus con- 

 structed anew to suit the new functional 

 demand, but is merely modified more or 

 less profoundly for the new duty. This 

 makeshift character of organs is the solid 

 basis of morphology. Morphology thus 

 takes cognizance of the conservative tend- 

 encies which inhere in form and structure, 

 and is clearly separated from physiology 

 which deals with the actual functions alone 

 and their apparatus. 



Since the conservatism which inheres in 

 the form and structure of plants is the 

 peculiar province of plant morphology, it 

 can not afford to neglect the earlier and ex- 

 tinct vegetation which once peopled the 

 earth. Almost until the present moment 

 botanical morphology has labored, how- 

 ever, under a peculiar disadvantage in this 

 respect. In the case of fossil vertebrated 

 animals, which may be appropriately com- 

 pared with vascular plants, the processes 

 of decay, which accompany fossilization, 

 only serve to make the skeletal tissues, mor- 

 phologically the most important, stand out 

 the more clearly, so that they thrust them- 

 selves, as it were, on the gaze of the be- 

 holder and thus at once suggest comparison 

 with the similar structures of animals still 

 living. You are all aware of the extremely 

 important advances made in the earliest 

 third of the last century by the great 

 French anatomist Ci;vier in the study. 



particularly of the vertebrate skeleton. 

 Since the publication of his ' Ossemens Fos- 

 siles' and his 'Regno Animal,' there has 

 aways been on the part of the zoologists a 

 sufficient attention to the morphological 

 and phylogenetic significance of the hard 

 parts of animals, which are fortunately not 

 only morphologically constant, but also ex- 

 traordinarily resistent to decay. In the 

 case of plant fossils the conditions have 

 unhappily not been so favorable. Al- 

 though it has been realized, especially in 

 recent years, that the adaptations to en- 

 vironment, which so quickly affect the out- 

 ward form of plants, act with extreme 

 slowness on their fibrovascular skeleton, 

 comparatively little advantage to mor- 

 phology has resulted. Vegetable fossils, 

 during the process of fossilization, are 

 more subject to the ravages of decay than 

 are those of animals, and the decay is gen- 

 erally not of such a character as to set their 

 skeletal and morphologically important 

 parts in strong relief. Indeed it is very 

 frequently these parts which suffer first, 

 owing to the fact that they do not often 

 contain the antiseptic substances which are 

 generally present in the softer tissues. 

 Thus, for example, if it were not for the 

 remains of the leaves of dicotyledonous 

 plants in the Cretaceous, we should have 

 little evidence for the occurrence of the 

 Angiosperms at so early a geological epoch. 

 The only relics of dicotyledonous woods 

 which have come down to us are those 

 somewhat rare ones of the upper Cre- 

 taceous which have been carbonized by 

 fire. Thus in the Raritan beds there are 

 quantities of dicotyledonous charcoals, but 

 no remains of wood in the lignitic or other 

 ordinary conditions of fossilization. Even 

 when plant remains do show the very 

 significant hard tissues preserved, the 

 microscope is generally necessary for their 

 diagnosis. Plant fossils then, if we ex- 

 cept fossil leaves, do not ordinarily pre- 



