686 SYSTEMATIC BOTANY. 



Natural Order 270. Juncaginace^. — The Arrow-grass 

 Order. — Herbaceous marsh plants. Leaves with parallel 

 veins. Flowers perfect, whitish or greenish. Perianth small, 

 more or less scaly, inferior, in two whorls, each containing 

 three pieces. Stamens 6 ; anthers usually extrorse. Carpels 

 3—6, separate or more or less united ; ovules 1 — 2. Fruit dry, 

 separating into as many parts as there are carpels. Seeds 

 attached to axile or basal placentas, without albumen ; embryo 

 straight, with a lateral cleft {figs. 744 and 745). 



Distribution, ^c. — Found more or less in nearly all parts of 

 the world, but most abundant in temperate and cold regions. 

 Examples : — Triglochlin, Potamogeton, Ouvirandra. There are 

 7 genera, and 44 species. Their properties are unimportant. 



Natural Order 271. Alismace^. — The Alisma Order (figs. 

 1060 and 1061). — Swamp or floating plants. Leaves 



Fig. 1060. Fig. 1061. 



Fig. 1060. Flower of a species of Alisma, with an inferior perianth, arranged 

 in two whorls, each consisting of tliree parts ; six stamens ; and numerous 

 carpels Fig. 1061. Vertical section of the same. 



narrow or with an expanded lamina, parallel-veined. Flowers 

 perfect (figs. 1060 and 1061), or very rarely unisexual. 

 Perianth inferior, arranged in two whorls, each consisting of 

 three parts (fig. 1060) ; the outer Avliorl herbaceous, the inner 

 coloured. Stamens few (fig. 1060), or numerous ; anthers 

 introrse. Ovaries several (fig. 1060), superior, 1 -celled ; ovules 

 solitary, or 2-superposcd : placentas axile or basal (fig. 1061). 

 Fruit dry. Seeds without albumen ; embryo undivided, curved. 



Distribution, Sfc. — They arc principally found in the northern 

 parts of the world. Examples: — Alisma, Sagittaria, Actino- 

 carpus. There are 3 genera, and 50 species. 



Properties and Uses.— Of little importance. Many have fleshy 

 mealy rhizomes, Avhich are edible when cooked. Others possess 

 astringent properties. 



Natural Order 272. Butomace^. — The Butomus or 



