CONIFERALES (PINACEAE) 303 



but the history of the Pinaceae is not in a condition as yet to supply 

 such definite information. 



6. History 



The Coniferales are certainly very ancient, for remains of 

 undoubted conifers occur from the later Paleozoic (Permian) on, 

 and the total amount of material is enormous. Efforts have been 

 made to determine the material upon the basis of anatomical structure, 

 and the literature of paleobotany is full of names suggestive of affinities 

 with modern genera, but the results have been disappointing. Beau- 

 tifully preserved coniferous wood is common in Mesozoic deposits, 

 but no means have been found to determine, without peradventure, 

 even the tribes to which it belongs. Even the strong superficial 

 resemblances of leaf-bearing twigs and cones cannot be relied upon 

 to determine afiinities. For example, Hollick and Jeffrey (155) 

 have found that cretaceous coniferous remains referred with consider- 

 able confidence to Cupressineae, Podocarpineae, and Sequoia really 

 belong to Araucarineae. 



It would be a matter of very great interest if the affinities of the 

 permian conifers could be determined, for it would go far toward 

 determining the genetic relationships of the modern tribes. Recently 

 new methods have been introduced, in connection with the study of 

 mesozoic material, which promise to bring much nearer the knowledge 

 of affinities, and with it some knowledge of the evolution of this most 

 important group of gymnosperms. 



In 1900 Scott concluded (61) that there was no sure evidence 

 of Abietineae below the Cretaceous. In the Wealden (lowest Cre- 

 taceous) there. are dwarf shoots bearing fascicles of needle leaves, 

 which are so characteristic of Pinus as to leave no doubt that forms 

 allied at least to that genus existed; and at the same horizon abie- 

 tineous wood occurs. Later Zeiller and Fliche (82, 88) reported 

 the discovery of pine cones in the Jurassic of France. The discovery 

 was interesting not only because it brought to" light the oldest known 

 pines, but also because the cones represented the two main series of 

 existing pines (Strobus and Pinaster), and therefore the pines were 

 already well differentiated in the Jurassic. Recently Nathorst 

 (148) announced the discovery of numerous winged pollen grains 



