204 SAPINDACE^. 



noxious, in others furnishes valued articles of the dessert. Among the lat- 

 ter are the delicious Litchi, Longan, and Rambutan of the Indian Archipel- 

 ago, the baccate fruits of as many species of Nephelium ; and the succulent 

 arillus of the Akee-tree (Cupania or Blighia sapida) is a well-known article 

 of food on the western coast of Africa. Even the seeds of Dodonaea and 

 of a i&w other plants of the order are eatable. On the other hand, some 

 yield a narcotic poison of such virulence that the South American Indians 

 use them to envenom their arrows. Several are employed for stupefying 

 fish. The Soapberries, and to some extent the seeds and roots of the North 

 American Buckeyes, abound in a detergent, saponaceous matter, which 

 lathers freely in water ; whence they are used as a substitute for soap. 



The plants of the order are nearly all trees or shrubs, or are shrubby, rare- 

 ly herbaceous vines, climbing by tendrils, which belong to the inflorescence. 



The fourth sepal (in the order of succession in the quincuncial aestivation) 

 is directed to the axis of inflorescence in this family. 



Three tribes are represented in the United States ; which, commencing 

 with the Hippocastaneae, that they may stand next to the Maples, are defined 

 in the following 



Synopsis of the United States Genera. 



Tribe I. HIPPOCAST ANE^. — Ovules 2 in each cell. Cotyledons 

 very thick and fleshy, partly soldered together. — Leaves (except in Ungna- 

 dia) opposite and digitate. 



yEscuLus. (Plates 176, 177.) Calyx 5-lobed. Petals not appendaged. 

 Ovary sessile : the upper ovules ascending, the lower pendulous. — 

 Leaves opposite, digitate. 

 Ungnadia. (Plates 178, 179.) Calyx 5-parted. Petals fimbriate-crested. 

 Ovary stipitate : both ovules ascending. — Leaves alternate, pinnate. 

 Tribe II. SAPINDE^. — Ovules usually solitary. Embryo curved 

 or biplicate, rarely straight. — Leaves (with one exception) alternate. 

 Sapindus. (Plate 180.) Calyx 5-parted. Petals 5, regular. Pistil 

 central. Fruit baccate. Seed not arillate. — Leaves abruptly pinnate. 

 Cardiospermum. (Plate 181.) Calyx 4-parted. Petals 4, irregular; 

 the appendage of two forms. Pistil eccentric in the flower. Cap- 

 sule vesicular-inflated. Seeds marked with a heart-shaped arillus. 

 — Leaves 1 -3-ternate. 

 Tribe III. DODONE^. — Ovules 2 or 3 in each cell. Embryo spi- 

 rally convolute. — Leaves alternate. 



DoDON^A. (Plate 182.) Calyx 4 -5-parted. Petals none. Capsule 

 2-4-winged, septicidal. 



