236 THE AMERICAN NATURALIST [Vol. XLVI 



large leaf or foliar rays below the level of their fellows 

 presents another interesting problem in evolution, into 

 which there is not time to enter at present. It is enough 

 to say that the so-called primary or large rays of dico- 

 tyledonous stems are not primary or primitive struc- 

 tures at all, but are of secondary origin and formed from 

 what was originally wood, in order that the assimilates 

 from the leaves may more readily and conveniently be 

 stored for future use. We have thus an explanation of 

 the relation of the woody to the herbaceous stem, which 

 is at once in harmony with the general principles of plant 

 evolution and at the same time with physiological neces- 

 sities. The fallacy of considering the herbaceous as the 

 primitive type is further made clear. There is in fact 

 every reason to believe that the early Dicotyledones were 

 entirely woody perennials, just as the forbears of the 

 existing herbaceous Pteridophyta have been shown by 

 paleobotanical and anatomical investigations to have 

 been derived from arboreal ancestors of the Paleozoic. 



The clear realization of the universal validity of the 

 primary laws of plant evolution depends almost entirely 

 on our increased knowledge of the organization of fossil 

 plants. There has come to morphology as a consequence 

 of the study of ancient forms a new birth, quite compar- 

 able to the remarkable intellectual awakening in Europe, 

 at the beginning of the modern period, resulting from 

 the rediscovery of the ancient classics of the Greeks and 

 Romans. This awakening, known as the renaissance, has 

 its exact counterpart in plant morphology and our en- 

 thusiasm over the discovery of new fossil remains which 

 throw a light on the origin of existing plants is not dif- 

 ferent from that experienced by the enlightened citizens 

 of the Italian cities at the end of the middle ages, over 

 the unearthing of a new manuscript of Virgil or of 

 Horace. As a result of this impetus the morphologist 

 has already in the past decade revolutionized the system- 

 atic arrangement of the Gymnosperms and the work in 

 this special field has scarcely begun. In the case of the 



