FiCOIDALES.] 



MESEMBRYACE^. 



525 



K^?^fe 



Order CC. MESEMBRYACE^.— Ficoids. 



Flcoideae, Juss. Gen. 315. (1789); Diet. Se. Nat. 16. 528. (1820); DC. Prodr. 3. 415. (1828); Salm Dyck 

 Monogr. Mesemh. (18.34); Meisn. Gen.V2.9. — Mesembryaceae, Ed. pr. xxxviii.— Mesembryanthemeae, 

 EndL Gen. ccv. Fenzl. in Ann. Wien. Mus. 1. 347.— Lewisieae, Hook, in Beechey, p. 345.— Spaeta- 

 lumeae, Nuttall Fl. Rocky Mount, p. 24. 



Diagnosis. — Fkoidal Exogens, with numerous compicuous petals, and several consolidated 



carpels. 



Shrubby or herbaceous succulent plants, \\\i\\ opposite simple leaves. Flowers com- 

 plete, often showy, always terminal, although, from the shortness of the branches on 

 which they grow, apparently lateral ; often opening only under the influence of sunshine, 

 and closing in its absence. Sepals definite, usually 

 5, but varying from 4 to 8, more or less combined 

 at the base, either cohering with the ovary, or dis- 

 tinct from it, equal or unequal, with a quincimcial 

 or valvate aestivation. Petals indefinite, coloured, 

 in many rows. Stamens arising from the calyx, 

 indefinite, distinct ; anthers oblong, incumbent. 

 Ovary inferior, or nearly superior, many-ceUed or 

 one-celled ; stigmas numerous, distinct. Ovules 00, 

 amphitropal, attached by cords to a central pla- 

 centa, which is either whoUy free, or united to the 

 edges of the carpels, or sometimes spread over the 

 back of the ca^^ty of each cell. Capsule surrounded 

 by the fleshy calyx, many-celled or 1 -celled, 

 opening in a stellate manner at the apex, or when 

 free from the calyx splittmg at the base. Seeds 

 definite, or more commonly indefinite, attached to 

 the inner angle of the cells ; embryo lying on the 

 outside of mealy albumen, curved or spiral, with 

 the radicle next the liilmn. 



These are the most perfect of the Ficoidal Al- 

 liance, for the carpels are numerous and consoli- 

 dated, and the apparatus of the corolla abvmdant 

 and richly coloured. In this respect, indeed, 

 Ficoids approach the Torch-thistles, although other- 

 wise so different. They are to Ficoidals what 

 Purslanes or Cloveworts are to Silenals, the princes 



of their race. One of the most singular facts connected with them is the variable 

 nature of their placenta, which sometimes occupies the centre, to which the edges of 

 the carpellary leaves are closely apphed, sometimes nms up the back, altogether avoid- 

 ing the centre, as in Mesembryanthemum acinaciforme (See Ladies' Botany, vol. ii. 

 t. xxxi. 2.), and is sometunes absolutely free, as in Lewisia. This curious genus, how- 

 ever, differs a little from the rest of the Order m its perfectly one-celled free ovary, and 

 barely perigynous stamens. It is however near GUnus, and there does not seem to be 

 any necessity for regarding it as the iy^e of a peculiar Order. The seed-vessels of the 

 Ficoids exhibit remarkable phenomena, closmg when placed in water, opening again 

 when dried, a hygrometrical quality doubtless connected with their manner of life. 

 Inhabitants of the dry places of southern Africa, they only expand and discharge their 

 seeds when rain falls to relax theii' tissue, for then only would the seeds be able to 

 germinate. This is more especially evident m M. Tripolium, which has been sold under 

 the name of Flores Candiae. 



The hottest sandy plains of the Cape of Good Hope nourish the larger part of this 

 Order. A few are found in the south of Europe, north of Africa, Chile, Chma, Peru, 

 and the South Seas. !,• u • 



The succulent leaves of a few are eaten, as of Mesembryanthemum edule, which is 



CCCLVIII. 



Fig. CCCLVIII. — Mesembryanthemum. 

 divided perpendicularly. 



1. its fruit ; 2. the same opened ; 3. a seed : 4. the same 



