ZANTHOXYLACEiE. 149 



Plate 157. 



PTELEA, L. 



Flores polygami, 4-5-andri. Ovarium 2-loculare, stylo 

 brevi superatum : stigma 2-lobum. Friictiis samaroideus, 

 2-locularis ; loculis abortu monospermis. — Fmtices inermes ; 

 foliis plerumque 3-foliolatis ; floribus cymosis. 



Ptelea, Linn. Gen. 152. Mill. Ic. t. 211. Lam. 111. t. 84. Gserln. Fr. 



t. 49. DC. Prodr. 2. p. 84. Adr. Juss. in Mem. Mus. 1. c. p. 



510. t. 26. Torr.»fcGray,Fl.N.Am.l.p.2]4. Endl. Gen. 5977. 

 Bellucia, Adans, Fam. 2. p. 344. 



Shrub Trefoil. 



Flowers by abortion polygamous. Calyx of four or five 

 small and nearly distinct sepals, at first imbricated in aesti- 

 vation, deciduous. Petals 4 or 5, hypogynous, much longer 

 than the calyx, imbricated in aestivation, widely spreading, 

 deciduous. Stamens as many as the petals and alternate 

 with them, hypogynous, in the sterile flowers as long as the 

 corolla, in the fertile shorter and with smaller or imperfect 

 anthers : filaments subulate, thickened below, hairy on the 

 inside : anthers ovate or cordate, introrse, two-celled ; the 

 cells opening longitudinally. Pistil abortive in the sterile 

 flowers, in the fertile raised on a short and thick gynophore : 

 OVARY compressed, two-celled : style short : stigma two- 

 lobed. Ovules 2 in each cell, inserted one above the other, 

 but close together, on the middle of their inner angle, ampiiit- 

 ropous ; the upper one of each cell only becoming fertilized, 

 with the micropyle superior ; the lower pushed downwards 

 by the other, so that its micropyle becomes centrifugal. 



Fruit a two-celled samara, surrounded by a broad and 

 reticulated wing, orbicular, indehisccnt : the cells one-seeded. 

 Seed oblong, amphitropous, the short raphe ventral and basi- 

 lar, with a smooth or somewhat wrinkled coriaceous testa. 

 Embryo straight in the axis of fleshy albumen (nearly of its 



