NYCTAGINACE^. 



561 



Authors notice 19 genera, including 117 species. Examples — Mirabilis 

 (Nyctago), Boerhaavia, Pisonia. 



The plants of the order have in general purgative qualities. Mira- 



Pig. 791, 



Fig. 792. 



Pig. 793. 



i Jalapa was at one time considered the Jalap-plant, in place of 

 Exogonmm Pwga, one of the Oonvolvulaceee. M. dichotoma is the 

 Marvel of Peru, which is commonly cultivated in gardens. It is 



Pig. 796. 



Pig. 797. 



called in the West Indies " four o'clock flower," on account of opening 

 its blossoms at that hour in the afternoon. Some of the species of 

 Pisonia present a peculiar arrangement of the vascular bundles of the 

 woody stem, which resembles in appearance that of Endogens. 



Pigs. 791-797. Organs of fruotiflcation of Mirabilis Jalapa, iUustrating the natural order 

 Nyctaginaoeas. Pig. 791. Diagram of tlie flower, -witli an imbricated involucre, five divi- 

 sions of tbe periantli, five alternate stamens, and a unilocular ovary. Pig. 792. Lower 

 part of the flower cut vertically, i. Involucre, c, Base of the perianth, green and swollen 

 around the ovary, t. Part of its coloured tube, e. Lower part of the filaments, s, Part of 

 the style, o, Ovaiy, with its erect ovule. Pig. 793. Stamens, with convex swelling at the 

 base of the filaments. Pig. 794. Style and stigma. Pig. 795. Fruit enclosed by the 

 persistent and Indurated base of the 'perianth. Fig. 796. The same out vertically, i. 

 Involucre, c. Perianth. /, Pericarp, j), Perisperm. e. Curved peripherical embryo, sur- 

 rounding mealy albumen. Pig. 797. Horizontal section of the fruit, c. Perianth. (, 

 Integument of the seed with the pericarp, j), Perisperm. r, Eadicle. m. Cotyledons. 



2 



