622 SYSTEMATIC BOTANY. 



acetosa is sometimes used medicinally for its refrigerant, diuretic, and anti- 

 Fcorbotic properties. In times of scarcity, it has been employed in Scan- 

 dinavia as a substitute for bread. The root of /'. Ilydrolapathiim, Great 

 Water Dock, is astringent and antiscorbutic. The roots of R. alpinus are 

 purgative, and were formerly employed instead of Rhubarb under the name 

 of Monk's Rhubarb. 



Natural Order 181. Nyctagixace.'e. — The ]^Tarvel of Peru 

 Order. — Character. — Herbs, shrubs, or trees, with the stems 

 usually tumid at the joints. Leaves generally opposite. Flowers 

 with an involucre. Calyx tubular or funnel-shaped, often co- 

 loured, plaited in sestivation, contracted towards tlie middle, its 

 base persistent and ultimately becoming indurated and forming 

 a spurious pericarp. Stamens 1 or many, hypogynous. Ovary 

 superior, 1 -celled, with a single ovule ; style 1 ; stigma 1. Fruit 

 a utricle, enclosed by the hardened persistent base of the calyx, 

 which forms a spurious pericarp. Seed solitary {fig. 762) ; em- 

 bryo coiled round mealy albumen {fig. 762), with foliaceous 

 cotyledons, and an inferior radicle. 



Distribution, cfc. — Natives exclusively of warm regions. Ex- 

 ampks of the Genera: — Mirabilis, Pisonia. There are about 

 100 species. 



Properties and Uses. — Chiefly remarkable for the presence of 

 a purgative property in their roots ; this is especially the case 

 with Mirabilis Jalajm and M. longiflora. M. Jalapa was long 

 erroneously regarded as the source of our officinal Jalap. M. 

 dichotoma is commonly known under the name of the Pour- 

 o'clock plant, from opening its flowers in the afternoon. Boer- 

 havia diffusa is said to possess expectorant properties. 



Natural Order 182. Amaranthace^e. — The Amaranth Order. 

 — Character. — Herbs or shrubs. Leaves simple, exstipulate, 

 opposite or alternate. Flowers crowded, spiked or capitate, 

 bracteated, perfect or occasionally unisexual. Ccdyx of 3 — o 

 sepals, dry and scarious, persistent, often coloured. Stametis 5, 

 hypogynous and opposite to the sepals, or a multiple of that 

 number; anthers 2 or 1-celled. Ovary free, 1-celled, with 1 or 

 more ovules ; style 1 or none ; stigma simple or compound. Fruit 

 a utricle, a caryopsis, or a berry. Seeds 1 or more, pendulous ; 

 embryo curved round mealy albumen ; radicle next the hiluni. 



Distribution, cf-c. — The plants of this order are most abundant 

 in tropical regions, and are altogether unknown in the coldest 

 climates. Examples of the Genera: — Celosia, Amaranthus. 

 There are nearly 500 species. 



Properties and Uses. — Unimportant. Anmraoithus spinosus 

 and other Indian species possess mucilaginous properties. 

 Another Indian species, Achyranthcs aspera, is also reputed to be 

 astringent and diuretic. Gomphrena officincdis and G. macroce- 

 phcda are used in Brazil in intermittent fevers, diarrhoea, and 

 some other diseases. Some of the species have bright-coloured 

 persistent flowers, and are hence cultivated in our gardens, as 



