PALEOBOTANY BEERY. 367 



has numerous extinct species and goes back to the Lower Cretaceous 

 (Pinites or Abietites), Cedrus goes back to the Lower Cretaceous, 

 Picea and Abies to the dawn of the Upper Cretaceous, while Tsuga, 

 Pseudotsuga, and Larix are exclusively Tertiary and Recent. The 

 family is especially varied and widespread in the relatively short 

 period from the Oligocene to the Recent. 



PHYLUM ANGIOSPERMOPHYTA. 



The taxonomy of the angiosperms is still in a most unsatisfactory 

 state. The chief steps in their classification have been taken by 

 Ray (1703), Jussieu (1789), De Candolle (1819), Endlicher (1836- 

 1840),Brongniart (1843),Braun (1864), Bentham and Hooker (1862- 

 1883 ) , Eichler ( 1883 ) , and Engler ( 1892 ) . While very imperfect and 

 founded to a too great degree upon floral morphology the classifica- 

 tion proposed by Engler and derived largely from Eichler's work is 

 the most satisfactory, and it has the additional advantage of having 

 been elaborated in a general systematic treatise. 



In contrasting the angiosperms with the coniferophytes or with any 

 of the other great groups of seed plants, one is impressed with the lack 

 of knowledge of both recent and fossil forms. Making their appear- 

 ance in the geological record during the Lower Cretaceous, they soon 

 outdistanced all competitors and from the Eocene to the present they 

 have been the dominant plant group. Over 100,000 existing species 

 are known, and the fossil forms, even in the relatively short period of 

 their dominance, probably outnumber the recent, so that vast numbers 

 of species and very imperfect knowledge render a generalized presen- 

 tation well nigh impossible. 



The angiosperms undoubtedly show the most perfect adjustment 

 of the plant organism to a strictly terrestrial existence. Adaptable 

 to a degree unequaled in other phyla they inhabit the most diversified 

 environments, and some have secondarily invaded the sea margins as 

 well as the lakes and streams, while others have become parasites, 

 saprophytes, or epiphytes. The modification of their flowers for se- 

 curing cross-pollination through the agencies of insects or birds is well 

 known, as are the various modifications of fruits and seeds for dis- 

 persal by wind, mechanical ejection, floating, passing unharmed 

 through the alimentary tract of birds or mammals, sticking or cling- 

 ing to fur or feathers, etc. Ranging in size from tiny aquatics to 

 giant trees several hundred feet tall, and ranging in their life span 

 from that of a single season to several thousand years, they are the 

 most impressive members of the vegetable kingdom. Fruits are con- 

 fined almost exclusively to angiosperms and are apparently one of 

 the effects of fertilization, as specializations for protection and dis- 

 persal of the seeds. 



