WALNUTS AND HICKORIES BERRY. 



327 



in the relatively short time, geologically speaking, that has elapsed 

 since the dawn of the Tertiary. 



The principle has frequently been enunciated that when closely 

 related forms are found in the existing flora of the w^orld, restricted 

 in range and isolated from their nearest relatives, or when other 

 existing genera are monotypic, it is quite safe to predict an inter- 

 estmg and extending geological history. Engelhardtia proves to be 

 another illustration of this principle, for its peculiar three-winged 

 fruits have been known in the fossil state for almost a century. 

 They were long unrecognized, however, and the earlier students who 

 described them compared them with the somewhat similar winged 

 fruits of the genus Carpinus (Betulaceae). With the botanical ex- 

 ploration of distant lands in the early part of the nineteenth cen- 



FiG. 3. — Engelhardtia (Orcomunnea) mississipinensis Berry, from the lower 

 Eocene of Mississippi (natural size). 



tury, specimens of Engelhardtia began to be represented in the larger 

 European herbaria, and Baron Ettingshausen, that most sagacious 

 of paleobotanists, as long ago as 1851 pointed out that certain sup- 

 posed species of Carpinus were really fruits of Engelhardtia. He 

 returned to the subject in 1858 without, however^ actually changing 

 the names of any of the supposed species of Carpinus, nor does he 

 seem to have been aware of the existence of a living species of Engel- 

 hardtia (Oreomumiea) in Central America. 



Since Ettingshausen's announcement a dozen or more fossil species 

 have been described. The oldest known European form occurs in 

 the upper Eocene or lower Oligocene (Ligurien) of France, and the 

 species become increasingly abundant throughout southern Europe 



