370 



SCIENCE 



[N. S., Vol. XL., No. 1028 



evolutionary story of the Angiosperms. I 

 do not anticipate that any great measure 

 of success, beyond what is shown in a very 

 polysyllabic terminology, and an appear- 

 ance of knowing more than the facts can 

 quite justify, will attend such efforts. It 

 would seem to me to be more in accord 

 with the dictates of true science to proceed 

 in a different way, as indeed many workers 

 have already been doing. To start not 

 from preconceptions based upon limited 

 paleontological data, but from an intensive 

 study of the living plants themselves. To 

 widen as far as possible the criteria of 

 comparison, by making, for instance, every 

 possible use of cellular, physiologico- 

 chemical, and especially secretory detail, 

 •and of minor formal features, such as the 

 <dermal appendages, or by initiating a new 

 'developmental morphology of the flower 

 (from the point of view of its function as a 

 whole; and with its physiological end 

 elearly in sight, viz., the maturing, nourish- 

 ing, and placing of new germs. To make 

 on some such basis intraordinal, and in- 

 trageneric comparisons with a view to the 

 phyletic seriation of closely related forms; 

 and so to construct probable short series, 

 which may subsequently be associated into 

 larger phyletic groupings. This should be 

 checked wherever possible by physiological 

 probability. A keen eye should be kept 

 upon such information as geographical 

 distribution and paleontology may afford, 

 and especially upon the fossils of the 

 Mesozoic Period. What is above all needed 

 for success among the Angiosperms is new 

 criteria of comparison, to meet the far- 

 reaching difficulties that follow from 

 parallel development and recent adapta- 

 tion. If some such methods be adopted, 

 and strenuously pressed forward, the task 

 should not appear hopeless, though it can 

 not be anything else than an arduous one. 

 I can not conclude without some remark 



on the bearing of parallel or convergent 

 development, so fully exemplified in the 

 Filicales, upon the question of the genesis 

 of new forms. Any one who examines, 

 from the point of view suggested in this 

 address, the larger and well-represented 

 divisions of the vegetable kingdom must 

 be impressed with the extraordinary dead 

 level of type to which their representatives 

 have attained. In most of these divisions 

 the phyletic history is obscured, partly by 

 the absence of any consecutive paleonto- 

 logical record, but chiefly by the want of 

 recognized criteria for their comparison. 

 This is very prominently the case for the 

 mosses, and the Angiosperms. 



But it may be doubted whether these 

 large groups differ in any essential point, 

 in respect of the genesis of their multi- 

 tudinous similar forms, from the Filicales, 

 in which the lines of descent are becoming 

 clearer through additional knowledge. 

 Suppose that we knew of no fossil ferns; 

 and that none of the early fern-types in- 

 cluded under the term "Simplices" had 

 survived in our living flora: and that the 

 Filicales of our study consisted only of the 

 2.500 living species of the old undivided 

 genera of Polypodium, Asplenium, Aspi- 

 dium and Acrostichum. Then the phyletic 

 problem of the Filicales would appear as 

 obscure as does that of the mosses, or of 

 the Angiosperms of the present day. They 

 would present, as these great groups now 

 do, an apparent dead level of sameness in 

 type, though the phyletic starting-points in 

 each may have been several and distinct. 

 There is every reason to suppose that in 

 the phylesis of the mosses or the Angio- 

 sperms also there has been a parallel, and 

 even a convergent, development of the same 

 nature as that which can be cogently 

 traced in the Filicales: but that it is ob- 

 scured by the obliteration of the early 

 stages. Internal evidence from their com- 



