Natural History of the United States. 211 



living plants cannot be fully understood without a thorough 

 acquaintance with the fossils and their distribution in the succes- 

 sive geological formations, and that this case exhibits one of the 

 most striking examples of the influence classification may have 

 upon our appreciation of the gradation of organized beings in the 

 course of time. As long as Gymnosperms stand among Dicotyle- 

 dones, no relation can be traced between the relative standing of 

 living plants and the order of succession of their representatives 

 in past ages. On the contrary, let the true affinity of Gymnos- 

 perms with Ferns, Equisetaceaa, and especially with Lycopodiaceae 

 be fully appreciated, and at once we see how the vegetable king- 

 dom has been successively introduced upon earth, in an order 

 which coincides with the relative position its primary divisions 

 bear to one another, in respect to their rank, as determined by 

 the complication of their structure. Truly, the Gymnosperms, 

 with their imperfect flower, their open carpels, supporting their 

 polyembryonic seeds in their axis, are more nearly allied to the 

 anathic Acrophytes, with their innumerable spores, than to either 

 the Monocotyledones or Dicotyledones; and, if the vegetable 

 kingdom constitutes a graduated series beginning with Crypto- 

 gams, followed by Gymnosperms, and ending with Monocotyle- 

 dones and Dicotyledones, have we not in that series the most 

 striking coincidence with the order of succession of Cryptogams, 

 in the oldest geological formations, especially with the Ferns- 

 Equisetaceae, and Lycopodiaceae of the Carboniferous period, fol- 

 lowed by the Gymnosperms of the Trias and Jura and the Mono- 

 cotyledones of the same formation and the late development of 

 Dicotyledones? Here, as everywhere, there is but one order, 

 one plan in nature." 



The discussions to which we have referred, are all regarded by 

 our author as introductions to the classification of animals ;. a 

 most just and noble view, since when classification sinks to be a 

 mere matter of arbitrary naming or even a convenient arrange- 

 ment of structures, it foregoes its highest aims. We now know 

 that there is in nature plan and system, depending upon the 

 arrangements of the Creator, and appreciable to our minds. This 

 plan, in so far as we have yet attained to its comprehension, 

 marks the true relations of animals and plants as products of a 

 thinking mind, and relates not only to structures but to embryonic 

 development, habits, geographical and geological distributions. 

 Classification in nature thus rises from its minute facts and. 

 structures, to a great philosophical system of the universe.. 



