FiCOIDALES.] 



TETRAGONTACEiE. 



527 



Order CCI. TETRAGONIACEiE.— Aizoons. 



Tetragouiaceae, Ed. pr. p. 209. (1836).— Tetragonieae, Aizoidetc, Sesuviese, Endl. Gen. p. 947.— 

 Sesuviaceae, Wight. Illustr. 2. 42. 



Diagnosis. — Ficoidal Exogensj with no petals, and several consolidated carpels. 



Succulent-leaved herbaceous plants, or occasionally small shrubs. Leaves alternate, 

 often covered with watery pustules, without stipules. Flowers small, axillary. Calyx 

 3- 5-cleft, free, or partially adherent to the ovary. Co- 

 rolla 0. Stamens definite, alternate with the sepals, 

 if they bear any relation to them. Ovary 2- 9-celled ; 

 ovules suspended or ascending, solitary or several, ana- 

 tropal, always with a long cord ; foramen superior in 

 the suspended species. Styles as many as the cells of 

 the ovary, distinct. Fruit either an indeliiscent tough- 

 shelled nut, or a capsule splitting all round. Seeds with 

 an aimular embryo, curved round mealy albumen. 



The distinction of Aizoons resides in their want of 

 petals and small number of stamens, otller^\^se they are 

 like Ficoids. They pai'ticipate m the affinity 

 of that Order, but approach nearer to the 

 Chenopods, among which Beta has the ad- 

 herent calyx of a Tetragonia. Cypselea, 

 and the genera near it, also establish a con- 

 nection with Pm'slanes, wliich are positively 

 known by theu* 2-leaved calyx. 



The species, which are plants of no beauty, 

 are found in the South Sea Islands, the 

 residence more especially of Tetragonias, in 

 the Mediterranean, the Cape of Good Hope, 

 or various parts of the tropics. 



They are universally insipid or shghtly saline, whence they are suited for human food. 

 Tetragonia expansa, a New Zealand annual, is a good deal cultivated in Europe under 

 the name of New Zealand Spinage, as a substitute for which herb it is employed. Sesu- 

 vium portulacastrum and repens are used for the same purposes in the tropics of 

 Asia. The ashes of Aizoon canariense and hispanicum abound in soda. 



Fig. CCCLIX. 



GENERA. 



Suborder I. Tktbago- 

 NE«. — Fruit woody, 

 indehiscent. 



Tetragonia, Litm. 

 Demidovia, Pall, 

 Tetragonocarpn.<!, Com. 



Tetragonella, Miq. 

 Aizoon, Linn. 



Veslingia, Fabric. 



Ficoidece, Dillen. 

 Galenia, Linn. 



Kolleria, Presl. 



Sialodes, Eckl. et Zeyh. 

 Plinthus, Fenzl. 



Suborder II. Sesuve^. 

 — Capsule circumscis- 



sile. 



Trianthema, Sauv. 



Rocama, Forsk. 



Paptilaria, Forsk. 



Zaleya, Burm. 

 Diplochonium, Fenzl. 



Sesuvium, Linn. 



Aizoon, Andr. 



Halimus, Loffl. 

 Pyxipoma, Fenzl. 

 Ancistrostigma, Fenzl. 

 Cypselea, Turp. 



Radiana, Raf. 



Millegrana, Surian. 



Numbers. Gen. 11. Sp. 65. 



ChenopodiacecB. 

 Position. — Mesembryacese. — Tetragoniace.e. — Scleranthacese. 



PortulacecB. 



Fig. CCCLIX.— Tetragonia. 1. a flower; 2. the calyx opened out; X ripe fruit; 

 section of it ; 5. an ovule ; fi. a section of a seed. 



4. a transverse 



