DESCRIPTION OF SPECIES— NYCTIAGINE^. 209 



up, cutting across the veins and dividing the areas, as it is seen on tlie riglit 

 side of fig. 7. The veins arc all very black, while the color of the leaves or 

 of the prints upon the stones is yellow. The substance is somewhat thick, 

 not positively coriaceous, but membranaceous. The inflated midrib is not 

 observed upon any specimens of the living species which I had for compari- 

 son ; it is, however, a character of some PoligonecB, a family to which the 

 CrednericB, of the Cretaceous were referred on that account. 

 Habitat. — Carbon, Wyoming. 



NYCTIAGINE^. 



PISONIA, Plum. 



A genus represented, like the former, by arborescent species distributed 

 more generally in the tropical regions of the whole world. The leaves are 

 generally oval or obovate, entire, of a hard consistence, with a strong midrib 

 and delicate, distant, secondary veins. The flowers or fruits are persistent, 

 corymbose, and cymose ; these characters, rather than those of the leaves, are 

 important for the evidence of generic identity. Four fossil species only have 

 been described from the Tertiary of Europe. One only, Pisonia Eocenica, 

 Ett., has been found with the leaves and the organs of fructification. Two 

 living species inhabit Florida: P. aculeata, L., and P. oblusata, Swartz. 



Pisonia racemosa, Lesqz. 



Plate XXXV, Fig. 4. 



Pisonia racemosa, Lesqx., Annual Report, 18; 3, p. 400. 



Leaves small, membranaceous, entire, obovate, rounded, or very obtuse at the point, gradually 

 narrowed downward to a flexuous tbiu petiole, triple-nerved at the base. 



The only leaf which we have of this species is marked by four pairs of thin 

 veins, parallel, inequidistant, in an acute angle of divergence of about 30°, curv- 

 ing quite near the borders; the areolation obsolete. The fruits, or unopened 

 receptacles or buds, are in branched corymbs,or clusters, of six to eight, short- 

 pediceled, either erect or horizontal or pending achenia (?), which are short, 

 narrowly ovate, acute, rounded, or narrowed to the base, borne on filiform 

 pedicels. This species is allied to P. Eocenica, Ett. (Fl. v. Har., p. 43, pi. xi, 

 figs. 1-22), differing especially by its much shorter achenia, in more divided 

 racemes. D'Ettingshausen compares the fruits (?) of his species to the 

 14 T r 



