LESSONS IN BOTANY. 



187 



persistent under the form of doable membranous triangular leaf* 

 liko appendage*. 



Many species of this natural order are cultivated for the beauty 

 of their flowers ; tome, too, are unoful. The succulent loaves 

 contain many salts, especially oxalate of lime; some are sapid 

 and saccharine. The ice-plant (Meaemlryanthcniuin cryital- 

 whirl, in a very common growth in the Canary Inland* 

 rmd the Mediterranean region, ia charged with gelatinous 



below, and thus forming an elongated tube ; stamen* numerous, 

 multi-serial, inserted upon the base of the ccroila; ovary inferior, 

 unilocular ; placentas parietal, mnlti-ovular ; berry pulpy ; seeds 

 numerous, dicotyledonous ; embryo straight or curved ; albumen 

 absent or scarcely visible. 



The Cactaceas are American plant* ; they are ligneous and 

 fleshy ; their stem is branched or simple by the rappreasion of 

 buds ; cylindrical, fluted, flat, or globular (Fig. 219), covered 



220. THE OAKLAND RYKINOA (PHILADELPHUS CORONARIUS). 221. STONECROP (8EDUM). 222. PURPLB MESEMBRYAKTHEMUM (XXSEXBBT4 

 THEMUX FULCIDUM). 223. SICKLE-SHAPED MKSKMIIRYASTHEMUM (MESEMBRYANTHEMUM FALCIFOUME). 221. SCARLET CRASSULA (CRAS- 

 BULA COCCINXA). 225. NEW HOLLAND PITCHER PLANT (CEPHAI.OTUS FOLLICULARIS). 226. BLOSSOM OF NEW HOLLAXD PITCHEB PLANT. 



vesicles, which canso it to appear, whsn shining in the sun's 

 rays, as if covered with a crest of hoar-frost. The inhabitants 

 of the Canary Islands burn ';his plant for the purpose of ex- 

 tracting,- coda from its ashes. The fruit of the Hottentot fig- 

 marigold (Mesembryanthemum edule) is eaten as food by the 

 Hottentots. Mesem&ry inthemum fulgidiim is a favourite object 

 of culture on account of the extreme beauty of its deep purple 

 flowars (Fig. 222). Another species is figured in Fig. 223. 



SECTION LXXI. CACTACE.E, OE INDIAN FIGS. 



Characteristics : Calyx adherent to the ovary ; with pluri-serial, 

 petaloid limb, indistinguishable from the corolla ; petals nume- 

 rous, pluri-serial, imbricated in aestivation, inserted upon the 

 Bummit of the calycinal tube, sometimes free, sometimes coherent 



with teat-like tubercles, the ropreaentativas of abortive branches. 

 The leaves are generally absent, or at most indicated by a small 

 cuhhion-like excrescence lying beneath a bud ; sometimes per- 

 fect, plane and petiolate, as in the case of Pereskia, the Barba- 

 does gooseberry ; the buds situated in the axilUe of the abortive 

 leaves are of two orders, the inferior ones are covered with 

 spines, whilst the superior ones are developed in branches or in 

 flowers. 



The berries of many of the Cactus tribe are employed in medi- 

 cine as a remedy for bilious affections. The Opuntia vulgaris, 

 or prickly pear, has long been naturalised in the Mediterranean 

 regions ; also the Nopal plant, or Opuntia cochinellifera. Upon 

 these plants thrive the valuable cochineal insect, from which 

 carmine and carmine lake are extracted. 



