THE POLYPETALOUS ORDERS. 401 



tate or palmate leaves. Flowers irregular. Calyx of five colored, 

 united sepals, the lower one spurred. Petals five ; the two upper 

 arising from the throat of the calyx, remote from the three lower, 

 which are stalked. Stamens eight, unequal, distinct. Ovary three- 

 lobed, composed of three united carpels; which separate from the 

 common axis when ripe, are indehiscent, and one-seeded. Seed 

 filling the cell, without albumen : cotyledons large, thick, and con- 

 solidated. Ex. Tropaeolum, the Garden Nasturtium, from South 

 America, where there are a few other species, one of which bears 

 edible tubers. They possess the same acrid principle and anti- 

 scorbutic properties as the Cruciferse. The unripe fruit of Tropse- 

 olum ma jus is pickled, and used as a substitute for capers. 



753. Ord, Limnanthaceae differs from the last only in its regular 

 and symmetrical blossoms, and the erect instead of suspended 

 seeds ; the calyx valvate in aestivation. Ex. Limnanthes of Cal- 

 ifornia, and Floerkea of the Northern United States. 



754. Ord, Rutaceffi (the Rue Family). Herbs, shrubs, or trees ; 

 the leaves dotted and without stipules. Flowers perfect. Calyx 

 of four or five sepals. Petals four or five. Stamens as many or 

 two to three times as many as the petals, inserted on the outside of 

 a hypogynous disk. Ovary three- to five-lobed, three- to five-celled, 

 with the styles united, or distinct only at the base, during ripening 

 usually separating into its component carpels, which fire dehiscent 

 by one or both sutures. Seeds few, mostly with albumen ; and a 

 curved embryo. Ex. Ruta (the Rue), Dictamnus (Fraxinella), 

 of Europe, &c., and Rutosma of Texas. Diosma and its allies, of 

 the Cape of Good Hope and New Holland, form a suborder, or a 

 closely allied order. Remarkable for their strong and usually un- 

 pleasant odor, and their 'bitterness (as in the common Rue of the 

 gardens), owing to a volatile oil and a resinous matter ; the former 

 is so abundantly exhaled by the Fraxinella in a hot, dry day, that it 

 is said the air which surrounds it may be set on fire. Many plants 

 of the Diosma tribe, especially those of Equinoctial America, con- 

 tain a bitter alkaloid principle, and possess valuable febrifugal 

 properties. The most important is the Galipea, which furnishes 

 the Angostura bark. 



755. Ord. Zanthoxylaceas (the Prickly-Ash Family). Trees or 

 shrubs ; the leaves without stipules, and punctate with pellucid dots. 

 Flowers polygamous or dioecious. Calyx of three to nine sepals. 

 Petals as many as the sepals, or wanting. Stamens as many or 



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