248 BERRY— LOWER EOCENE FLORA OF [April 25, 



Their fossil history is ahnost entirely unknown. The single Wil- 

 cox representative of the family is a flower described as Solanites, a 

 genus founded on the somewhat younger remains of a similar flower 

 found in the Sannoisian of France, and comparable with the existing 

 South American genus Saracha Ruiz & Pavon, as well as with With- 

 eringia, Solanum, etc. 



The last order of Gamopetalse positively recognized in the Wilcox 

 flora is the Rubiales which includes over 5,000 existing species segre- 

 gated into five families, over four fifths being referred to the family 

 Rubiaceae — the only one represented in the Wilcox. 



The Rubiacese includes about 355 genera and over 4,500 existing 

 species of herbs, shrubs and trees ; with simple, opposite or verticil- 

 late, mostly stipulate, leaves. They are widely distributed and 

 largely tropical. While the Wilcox representation is confined to a 

 single species each of Exostcma, Psychotria and Guettarda, great in- 

 terest must attach to the fossil record of so highly organized a family 

 which is my justification for introducing the following brief sketch 

 of our knowledge of it. 



No less than twenty-five genera have been recognized in the fossil 

 state. With the exception of the very doubtful determination of a 

 species referred to Rubier phyUum from the Turonian of Bohemia and 

 doubtless representing a species of Ericaceae, the family is unknown 

 in the Upper Cretaceous. It is however represented in the early 

 Eocene both in America and Europe. The Wilcox forms represent 

 a species of Exostema Rich., close to the existing Exostema cari- 

 baeum R. & S. which ranges from the Florida keys to Central Amer- 

 ica. The genus comprises about twenty existing species of shrubs 

 and small trees confined to the tropics and subtropics of America. 

 The second Wilcox species is referred to Guettarda Endlicher, a 

 genus of about fifty species mostly confined to the American tropics 

 but including one or two cosmopolitan tropical maritime species. 

 The Wilcox form is very close to the existing Guettarda elliptica 

 Swartz, a small tree of the Florida keys, Bahamas and West Indies. 

 The third Wilcox species is Psychotria grandifolia described origi- 

 nally by Engelhardt from the early Tertiary of Chili. The genus 

 Psychotria Linne comprises about 350 existing species of shrubs and 

 small trees in tropical America. Asia and the East Indies, two thirds 



