382 RHIZOBOLACE^:. 



mus forming a fleshy or glandular disk, into which the stamens are 

 often inserted. Ovary trilocular, rarely bi- or quadri-locular; ovules 

 anatropal, definite; style either undivided or 2 -3 -cleft. Fruit either 

 fleshy and indehiscent, or samaroid, or capsular, and 2-3-valved. Seeds 

 solitary, often arillate, exalbuminous ; embryo straight, curved, or 

 spiral; cotyledons incumbent; radicle next the hilum. Trees or 

 shrubs, sometimes climbing herbaceous plants, Avith alternate, some- 

 times opposite, compound (fig. 176), rarely simple leaves, often marked 

 with lines or pellucid dots. They are natives principally of South 

 America and India. In this order are included the Hippocastaneae or 

 Horse-chestnuts, which are distinguished by their opposite leaves, and 

 their two ovules in each cell, one ascending, the other suspended (fig. 

 428). Lindley gives 50 genera, including 380 species. Examples 

 Sapindus, Paullinia, Nephelium, ^Esculus, Pavia, Dodonasa, Mehosma. 



807. In this order are included many plants which yield edible 

 fruits, and others which are poisonous. A saponaceous principle exists 

 in certain species. The fruit of Sapindus Saponaria, under the name 

 of Soap-berries, is used as a substitute for soap in the West Indies. 

 The Longan and Litchi are excellent Chinese fruits, the produce of 

 Nephelium Longan and N. Litchi. The kernel of the Longan powdered, 

 is sometimes made into paper. Blighia or Cupania sapida yields the 

 Akee fruit, the succulent arillus of which is used as food. Many of the 

 Paullinias are poisonous. From the seeds of Paullinia sorbilis, how- 

 ever, the Guarana bread is prepared in Brazil. This Guarana contains 

 a bitter principle, identical with Caffeine. The bark of jEsculus 

 Hippocastanum, Horse-chestnut, has been recommended as a febrifuge, 

 and its seeds have been used as a substitute for coffee. The fruit 

 and leaves of JEsculus ohiotensis, the Buck-eye or American Horse- 

 chestnut, are said to be poisonous. Paullinia pinnata, and some other 

 Sapindaceas of Brazil, exhibit anomalous exogenous stems (fig. 106). 

 Ophiocaryon paradoxum, is the Snake-nut-tree of Demerara, and is 

 so caUed on account of the embryo resembling a coiled-up snake. 



808. Order 44. Rhizoboiaceae, the Souari-nut Family. (Polypet. 

 Hypog.} Sepals 5, more or less combined; sestivation imbricated. 

 Petals usually 5, unequal, thickish. Stamens indefinite, slightly 

 monadelphous, arising from a hypogynous disk, in a double row, 

 of which the inner is often abortive; anthers roundish, with longitu- 

 dinal dehiscence. Ovary 4-5-celled; ovules solitary, semi-anatropal ; 

 styles as many as the cells of the ovary; stigmas simple. Fruit formed 

 of several indehiscent, 1-celled, 1-seeded nuts, with a thick double 

 endocarp. Seed reniform, exalbuminous, with the funiculus dilated 

 into a spongy excrescence ; embryo with a very large radicle, which 

 constitutes nearly the whole of the kernel ; cotyledons small, lying in 

 a furrow of the radicle (fig. 503). Trees with opposite, pahnately 

 compound, coriaceous, exstipulate leaves. They grow in the warm 



