138 



they are rather allied to Zygophyllea: ; an opinion in which I am inclined to 

 concur, and which their compound leaves appear to confirm. Averrhoa differs 

 from the rest in its arborescent habit. They are generally described with an 

 arillus ; but, according to M. Auguste St. Hilaire, the part so called is nothing 

 but the outer integument of the seed. PI. Us. 43. 



Geography. Natives of all the hotter and temperate parts of the world, 

 most abundantly known in America and the Cape of Good Hope, and most 

 rarely in the East Indies and equinoctial Africa. 



Properties. Averrhoa Bilimbi and the pinnated Oxalis called Biophytum 

 have sensitive leaves. Their foliage is generally acid, so that they are fit to 

 supply the place of sorrel. Some of the species are astringent, and have been 

 employed in spitting of blood. Oxalis acetosella contains pure oxalic acid. 

 Turner, 623. Several species of Oxalis are used in Brazil against malignant 

 fevers. PI. Usuelles, 43. The fruit of Averrhoa is intensely acid. A species 

 of Oxalis found in Columbia bears tubers like a potato, and is one of the plants 

 called Arracacha. 



Examples. Oxalis, Biophytum, Averrhoa. 



CXXIV. TROPiEOLEiE. The Nasturtium Tribe. 



Tbop.eoleje, Juss. Mem. Mus. 3. 447. (1817) ; Dec. Prodr. 1. 683. (1824.) 



Diagnosis. Polypetalous dicotyledons, with definite hypogynous distinct 

 stamens, concrete carpella, an ovarium of 3 cells with the placentae in the axis, 

 an imbricated calyx with 1 of the sepals spurred, unsymmetrical flowers, de- 

 finite pendulous ovules, and indehiscent fruit. 



Anomalies. Magallana has winged fruit, 1-celled and 1-seeded by abor- 

 tion. In Trop. pentaphyllum, according to Aug. St. Hilaire {PI. Us. 41.), the 

 calyx is valvular, and the petals only 2. 



Essential Character. — Sepals 5, the upper one with a long distinct spur; (estivation 

 quincuncial. Petals 5, unequal, irregular, the 2 upper sessile and remote, arising from the 

 throat oi the calyx, the 3 lower stalked and smaller, sometimes abortive. Stamens 8, perigy- 

 nous, distinct; anthers innate, erect, 2-cclled. Ovarium 1, 3-cornered, made up of 3 carpella. 

 style 1 ; stigmas 3, acute ; ovula solitary, pendulous. Fruit indehiscent, separable into 3 pieces 

 from a common elongated axis. Seeds large, without albumen, filling the cavity in which 

 they lie ; embryo large ; cotyledons 2, straight, thick, consolidated together into a single body; 

 radicle lying within projections of the cotyledons.— Smooth herbaceous plants, of tender texture 

 and with an acrid taste, trailing or twining. Leaves alternate, without stipulaj, petiolate, with 

 radiating ribs. Peduncles axillary, 1-ilowcred. 



Affinities. Very near Geraniaceee, with which they agree even in then- 

 spur (which in Pelargonium is often present, but adnate to the pedicel), and 

 also Balsamineae, and Hydrocereae, from which they differ chiefly in the struc- 

 ture of their fruit. 



Geography. All natives of South America, mostly upon high land. 



Properties. The fleshy fruit of Tropa;olum niajus is acrid, and possesses 

 the properties of Cress ; and M. Decandolle remarks, that the caterpillar of 

 the Cabbage butterfly feeds exclusively upon Cruciferse and Tropaeolum. The 

 root of Tr. tuberosum is eaten in Peru. Tropaeolum pentaphyllum is used in 

 Brazil as an antiscorbutic, under the Portuguese name of Chaffas da Miuda. 

 PL Usuelles, 41. 



Example. Tropaeolum. 



