CALYCIFLOEiE. 539 



central, or parietal. Fruit capsular, or indehiscent. Seeds with 

 a curved or spiral embryo on the outside of mealy albumen. 



Division of the Order, and Examples of the Genera : — The Me- 

 sembryacese may be divided into three sub-orders as follows : — 



Sub-order 1. Mesemhryecs. — Leaves opposite. Petals numerous, 

 conspicuous. Stamens numerous. Fruit capsular, dehiscent. 

 Examples : — Mesembryanthemum, Lewisia, 



Sub-order 2. TetragonecB. — Leaves alternate. Petals absent. 

 Stamens definite. Fruit woody and indehiscent. Examples : 

 — Tetragonia, Aizoon. 



Sub-order 3. Sesuvece. — Leaves alternate. Petals absent. Sta- 

 mens definite. Fruit capsular, with transverse dehiscence. 

 Examples : — Sesuvium, Cypsela. 



The two last sub-orders are commonly placed in one order 

 called TetragoniacecB, which is then readily distinguished from 

 the Mesembryacese, by its plants having alternate leaves, no 

 petals, and but a small number of stamens. The plants compre- 

 hended in the above three sub-orders are, however, so nearly 

 allied, that I have placed them in one order as above. 



Disfributio7i and Nicmhers. — Natives exclusively of warm and 

 tropical regions. A large number are found at the Cape of 

 Good Hope. There are about 450 species. 



I*roptrties and Uses. — Several are edible; others yield an 

 abundance of soda when burned, but generally the plants of the 

 order are of little importance. 



Leicisia rediviva. — The root is eaten in Oregon. It is sometimps called 

 Tobacco-root from the smell of tobacco which it is said to acquire by cook- 

 ing. According to M. Geyer. it is the Racine am'ere of the Canadian Yoya- 

 geurs ; it forms a verj" agreeable and -wholesome food when cooked. 



Afesembnianthemum. — M.ci'ystaUinum is the Ice-plant. It is so called from 

 its surface being studded with little papiUte (see p. 58), of an ice-like appear- 

 ance. Its juice is reputed to be diuretic. The a.shes of this species, as well 

 as those of M. coptkum, M. nod{floi-um, and others, contain soda. J/. genkuJi- 

 florum is employed as a pot-herb in Africa, and its seeds are edible. J/, edule 

 is called the Hottentot's-Fig ; its leaves are eaten. The fruit of Af. cequila- 

 terale (Pig-faces, or Canagong) is eaten in Australia. 



Tetragonia expansa is used in New Zealand as a substitute for spinage. 

 It has been cultivated in Europe, and employed for the same purpose under 

 the name of New Zealand Spinage. It has been recently highly recommended 

 for cultivation in this country. Its flavom- is very similar to ordinary 

 spinage. 



Natural Order 94, Passifloeace.^. — The Passion-Flower 

 Order. — Character. — Herbs or shrubs, usually climbing by 

 tendrils {fig. 201). Leaves alternate, with foliaceous stipiiles. 

 Flowers perfect, or very rarely unisexual. Sepals 5, united be- 

 low into a tube, the throat of which bears a number of filamen- 

 tous processes : petals 5, inserted in the throat of the calyx on 

 the outside of the filamentous processes, with an imbricated aesti- 

 vation ; sometimes wanting. Stamens usually 5, monadelphous, 

 rarely numerous, surrounding the stalk of the ovarj-. Ovary 



