CALTCIFLOK^;. 269 



PORTULACACE^; are herbs with succulent leaves and regular un- 

 synimetrical flowers (sepals fewer than the petals) ; sepals 2, rarely 3 or 5 ; 

 petals mostly 5 or ; stamens variable. Capsule 1-o-celled, with few or 

 many seeds on long- funiculi from the base, or on a free central placenta; 

 embryo curved ; round floury perisperm. Illustrative Genera : Tetraffoma, 

 L. ; Aizoon, L. ; Portulaca, 1 ournef. ; Talinum, Adans. ; Claytonia, L. ; 

 Montici) Michel. 



Affinities, &c. This Order, as here regarded, has various relations, and 

 is not well defined. It approaches very closely to Caryophyllaceae through 

 Paronychiaceae, but may be distinguished by the 2-parted calyx and the 

 number and position of "the stamens. Like Paronychiaceae, the members 

 of this Order are nearly related to the proper apetalous Orders, Cheno- 

 podiaceae &c. Lindley separates the Tetragoniece, Aizoideee, and Sesuuiece 

 in an Order called Tetragoniaceaa, differing from Portulacaceae in their 

 apetalous flowers, multil ocular ovary, and distinctly perigynous stamens. 

 Portulacaceae would thus be defined chiefly by a 2-sepalous calyx, hypo- 

 gynous or rarely perigynous stamens, and 1-celled ovary. Bentham and 

 Hooker refer the Tetragonieae to Mesembryanthaceae, from which they 

 differ in their apetalous flowers. Portulaca is exceptional in its partially 

 inferior ovary and perigynous stamens ; hence the Order, as a whole, is 

 considered by Bentham and Hooker to belong rather to the Thalamiflorae 

 than to the Calyciflorae. The plants of this Order are generally diffused, 

 in waste, dry places. Portulaca oleracea, Purslane, is an old-fashioned 

 pot-herb ; others are used in the same way. Tetragonia expansa furnishes 

 New-Zealand Spinach. Claytonia tuberosa has an edible tuber. Many 

 have showy but ephemeral flowers. Leivisia rediviva (Oregon) has a 

 starchy root, used as food under the names of spatulum or spsetlum and 

 ratine amere ; it is pungent and aromatic when raw. 



MESEMBRYANTHACEAE on FICOIDE^E are shrubby or succulent 

 herbaceous plants, with opposite simple leaves ; sepals de"finite ; petals 

 very numerous ; stamens indefinite, perigynous; ovary inferior or almost 

 superior, many-celled or ] -celled; ovules numerous, attached by cords 

 to a free central placenta or to axile placentas, or to parietal placentas 

 spreading over the back of each cell ; seeds numerous ; embryo curved or 

 spiral, on the outside of mealy perisperm. Illustrative Genus : Mesem- 

 bi'1/anthemum, L. 



Affinities, &c. These plants are very nearly related to Portulacaceae and 

 Paronychiaceae. From the former they differ in the parietal, not free 

 central placenta, from the latter in the position of the stamens, many- 

 celled _ ovary, and dehiscence of the capsule. The structure of the ovary 

 is curious, presenting very different conditions in different members of 

 the Order ; probably it is somewhat analogous to that of Cucurbitaceae, 

 and the diverse positions of the placentas depend on the degree of involu- 

 tion of the Carpels and the disruption of the septa. The parietal placenta, 

 together with the presence of numerous petals, serve to indicate a rela- 

 tionship to Cactaceae. Bentham and Hooker refer to this Order Tetra- 

 goniece (see Portulacaceae) and Molluginea (see Paronychiaceae). The 

 plants are remarkable for their succulent foliage, accompanied sometimes 

 by water- vesicles or pseudo-glands on the epidermis, whence the name of 

 Ice-plant applied to Mesembryanthenmm crystallinum. The ripe capsuled 



