Paläoutolofiie. . 255 



the origin of all tbe groups antedates the beginning of the foßsil record and the latter 

 merely ehows them simultaneously reaching more modern expressions. 



Thus Jsoetcs, once believed an aucestor of Monocotyledons, is now found to be a 

 much reduced Lepidodenilron , and the evolution of the pteridophyte strobilus has been 

 from the complex fossil coues to the simpler living ones. Even tbe seed condition had 

 probably been reached by several groups of paleozoic literidopbytes. These are examples 

 of the changes in phylogenies brought aboiit bj- paleobotanical evidence. 



Our perspective of the group of Gymnosperms has changed greatly in the last de- 

 cade through increase in the knowledge of fossil forms. The whole uew group of Cycado- 

 filicales or Pteridosperms has been discovered, and they are the probable ancestors of 

 the Cordaitales at a time earlier than any known fossil records. The Mesozoic Bennetti- 

 tales, which also developed from this stock, is another group revealed by paleobotany. 

 And the paradox is further revealed, that the primitive Cycads were later in origin than 

 the Conifers and Ginkgos. The study of the anatomy of Mesozoic Coniferales has also 

 shown the relative ages of their various tribes and upset previous conceptions. General 

 conclusions ou phylogeny derived only from living forms, are more apt to be false 

 than true. Gates (London). 



701) Jeflrey, E. C. (Harvard, University), The relations of paleobotany to botany. 

 II. Morphology. In: Amer. Nat., Bd. 46, S. 225—238, 1912. 



Morphology originally concerned itself chiefly with the external form of the repro- 

 ductive structures, and paleobotany with the impressions on the rocks. Since the study 

 of iuteiTial anatomy has become a vital part of both morphology and paleobotany, the 

 two have been drawn more closely together. "Without the background supplied by our 

 increasing knowledge of fossil plants, the picture painted by the morphologist and em- 

 bryologist of the evolution of plants is without depth and entirely without perspective". 

 In the past, therefore, morphology has been largely fanciful in its attempts to construct 

 phylogenies. This has been relieved somewhat by the study of development and com- 

 parative anatomy, but the difficulty has always remained, to determine the direction in 

 which a series of forms should read. Thus the Taxaceae were put lower than the Pi- 

 naceae because of their simpler structure, but the paleobotanical record shows that the 

 Pinaceae are among the most äncient of the Coniferae, while the Taxaceae represent its 

 most modern development. Again, the Monocotyledons were placed by systematists below 

 the Dicotyledons because of their simpler Organization, but anatomical and paleobotanical 

 research shows that they represent a reduction from a dicotyledonous ancestry. The 

 three most important principles of morphology have to do with 1. recapitulation, 2. re- 

 version, and 3. retention. The first law is illustrated by studies of seedlings of Arattcaria 

 (Norfolk pine). It was found that their leaf traces were ephemeral, and that the pitting 

 of the xylem and the presence of wood parenchyma in the seedlings repeated abietinous 

 characters, hence strengthening the fossil evidence of their origin from an abietinous 

 stock. The broad and narrow rays of the Oak are used in further illustration of these 

 principles. The paper coucludes with a protest against the use of Latin diagnoses for 

 fossil plants. Gates (London). 



702) Hollick, A. (New York, Botanical Garden), The relations of paleobotany to 

 botany. III. Ecology. In: Amer. Nat., Bd. 46, S. 239—243, 1912. 



Paleobotany has supplied the explanations of numerous facts of geographic Isola- 

 tion, distribution, endemism, and the relationships of floras. Thus the giant redwood 

 (Sequoia) now confined to California, which was first discovered as a fossil and after- 

 wards recognized in the living form, is known to have had formerly a wide distribu- 

 tion through Siberia, Eastern Asia, Europe, and Greenland to Alaska and thence south- 

 ward to the present place of survival of the two remaining species. Similarly, the 

 Gymnosperm Taxodium is now confined to portions of the United States and Mexico, 

 but up to the close of the Tertiary period it flourished throughout temperate North 

 America and Eurasia. The peculiarities of the distribution of Sassafras, Eucalyptus, 

 Liriodendron and many other forms receive their explanation in the light of the distri- 

 bution of the earlier floras. Gates (London). 



Hierzu: Nr. 758. 



