PLIOCENE; PISLLYPAMPA BOLIVIA 185 



diverge from the midrib at wide angles, averaging about 70 

 degrees, pursue rather straight outward courses, and are 

 camptodrome in the marginal regions they are numerous, 

 parallel, and approximately equally spaced. The tertiaries 

 are obsolete by immersion. 



This fossil species resembles a number of existing forms 

 of Chrysophyllum in fact it is about the same size and shape 

 as the only tropical American species of this genus that 

 reaches Florida namely Chrysophyllum oliviforma La- 

 marck. It differs from this species in the more numerous 

 and more widely divergent secondaries. 



I was at first disposed to compare this fossil form with 

 the genus Clusia of the Guttiferse, which is also abundant in 

 tropical South America and ranges up the eastern Andean 

 slopes to altitudes of 3,100 meters. Clusia leaves are still 

 thicker than those of Chrysophyllum and tend to be larger, 

 widest above the middle, and with blunt or rounded tips. 

 The venation also shows differences. 



The genus Chrysophyllum, with between 50 and 60 exist- 

 ing species, is tropical or sub-tropical, most of its forms 

 being American, although it is represented in tropical Africa, 

 southern Asia, Australia, and the Sandwich Islands, and in all 

 tropical countries by the cultivated star apple, Chrysophyllum 

 cainito Linne, a native of the West Indies. Ten fossil forms 

 have been referred to this genus, all of which come from the 

 European Tertiary except one, a not very convincing form, 

 described by Engelhardt 22 from the Cenomanian of Sax- 

 ony, a species from the Miocene of Colombia described by 

 the same author, 23 and a third species described by the writer 

 from the lower Eocene of the Mississippi embayment 

 region. 24 



22 Engelhardt, H., Naturw. Gesell. Isis in Dresden, Sitz. 1891, abh. 

 7, p. 98, pi. 2, fig. 15. 



23 Engelhardt, H., Abh. Senck. Naturf. Gesell., Bd. 19, p. 31, pi. 

 5, fig. 7, 1895- 



24 Berry, E. W., U. S. Geol. Surv. Prof. Paper 91, p. 335, pi. 100, 

 fig. 7, 1916. 



