208 BERRY— LOWER EOCENE FLORA OF [April 25, 



The genus Ceanothus Linne with about forty existing species 

 confined to North America has included numerous fossil species sub- 

 sequently referred to Paliurus or Zizyphus. There are four re- 

 corded from the Upper Cretaceous of Greenland, New Jersey, Van- 

 couver Island and Westphalia ; two Eocene species recorded from 

 Greenland and British Columbia ; a Miocene species in Prussia, 

 Switzerland and 'Italy ; and a Pleistocene species in Kentucky. 



The next order, the Malvales, includes nine families and about 

 1,800 existing species. The Tiliace?e, Sterculiacese and Bombacacese 

 are the only ones represented in the Wilcox flora. The largest 

 modern family, the Malvaceae with over 800 species, many of which 

 are herbaceous and range from 65° North latitude (Russia) to 45° 

 South latitude (New Zealand), is not represented in the Wilcox. 

 The order displays somewhat uneven or but little understood phylo- 

 genetic characters but is evidently allied to the succeeding order, the 

 Parietales, through the family Elaeocarpacete. These inequalities of 

 evolution are shown among other ways by the complete syncarpy in 

 the Tiliaceae associated with an indefinite number of stamens and by 

 the complex arrangement of the stamens in the Sterculiaceas, associ- 

 ated with more or less incomplete union of the carpels. Both the 

 leaves, flowers and fruits exhibit a wide range of variation through- 

 out the order. 



The family Tiliaceae, represented in the Wilcox flora by a single, 

 not very common form of Grewiopsis, has about 35 genera and 370 

 existing species mostly of tropical lands and showing two centers cf 

 differentiation and distribution — ^one surrounding the Indian Ocean 

 and the other in northern South America. The geological history is 

 confined to the four genera Tilia (or Tilicephyllum) , Greuna, Grezin- 

 opsis and Apeibopsis.^' The genus Tilia Linne with 18 or 20 widely 

 distributed existing species in the north temperate zone (absent in 

 western North America and central Asia) has furnished about 25 

 fossil species based upon both leaves and fruits, the oldest known 

 being from the North American Eocene. There are no conclusive 

 Oligocene records except two French species, but about fifteen Mio- 



^^ The genus Lithca has been described from the Eocene of Sezanne 

 (Langeron) and from the Oligocene of Menat (Laurent), both French 

 localities. 



