CLASSIFICATION OF ANGIOSPERMS. 267 



ing principle is found in the berries of Phytolacca decandra and 

 Rivinia tinctoria of Venezuela. The leaves of some species of 

 Phytolacca are used as greens. 



e. AIZOACE^. This is a group of mostly tropical plants, 

 very many of them having fleshy leaves and adapted to arid 

 regions. Many of the plants, particularly those belonging to 

 the genus Mcscuibryanthcinuin, are much prized on account of 

 their beautiful flowers, which expand only in the sunshine. The 

 common ice-plant of the gardens, so called because of the numer- 

 ous glistening globules of water which cover the leaves, is .1/. 

 crystalliiiimi. This plant as well as other species of Mesembryan- 

 themum are used in medicine. The ashes yielded bv the plants 

 of this family also contain soda. The seeds of some species of 

 Mesembryanthemum as well as other m.embers of this family 

 are edible, and the leaves of some species are used as vegetables 

 like lettuce. 



f. PORTULACACE^. The plants are fleshy or succu- 

 lent herbs mostly indigenous to America. The two common 

 representatives are the spring beauty {Claytonia virginica), 

 the tubers of which are rich in starch, and purslane {Portn- 

 laca oleracea) sometimes used as a green vegetable. The 

 seeds of the latter plant as well as of other species of Portulaca 

 are used in medicine. 



g. CARYOPHYLLACE^. The plants are annual or 

 perennial herbs often swollen at the nodes, with opposite, entire 

 leaves, and usually perfect regular flowers. The perianth has a 

 distinct corolla of 4 or 5 petals. The fruit is a capsule and the 

 seeds are half anatropous. The plants are most abundant in tlie 

 northern hemisphere ; and some of them are quite showy, as the 

 CARNATION (Diaiitlius caryophyllus) and pinks {Dianthns spe- 

 cies) and the cultivated pink or Sweet William {D. barbatus). 

 A number of the members of this group contain saponin, as 

 bouncing bet (Saponaria officinalis), which is naturalized in the 

 United States from Europe, Gypsophila Strnthium of Spain and 

 other species of this genus, as well as species of Lychnis and 

 Herniaria. The leaves of Paronychia argcntca are used in Mo- 

 rocco as a substitute for tea. The roots of Scleranthiis perennis of 

 Eastern Europe are inhabited by an insect {Coccus polonica) 



