460 CIX. CACTE^. 



with many-ovuled parietal placentas. Beret pulpy. Seeds numerous. Embeyo 

 straight or curved, albumen or scanty. — Fleshy sheubs. Leaves generally or 

 rudimentary, rarely normal. 



Sheubs with watery or milky juice. Eoot woody, simple or brauching, bark 

 soft. Stem branching, or simple from the arrest of the buds, covered with tubercles 

 which represent the arrested buds, cylindric, angular, channelled, plane, winged, 

 elongate or globose, fleshy, with thick usually green bark, loose cellular tissue, 

 scanty and fragile, or rarely numerous and hard woody fibres, medullary sheath 

 broad. Leaves generally 0, indicated by a cushion under the bud, sometimes rudi- 

 mentary, deciduous, rarely perfect, flat and petiolate {Pereshia) . Buds springing from 

 the axil of the latent rudimentary or normal leaf, solitary or geminate and superim- 

 posed ; the lower arrested in its development, furnished with spines, naked or cottony ; 

 the upper close to it, developing into a flower or branch ; stipules ; spines springing 

 from the abortive buds, fascicled, definite or indefinite, rarely absent. TLOWEns 

 perfect, solitary, terminal or springing from the axil of an abortive branch, 

 ebracteate. Peeianth multiple, calyx hardly distinguishable from the corolla. 

 Caltx generally petaloid, rarely foliaceous, superior. Coeolla epigynous; peiaZs 

 delicate, 2-several-seriate, the inner largest, distinct and rotate {Opuntia, RhipsaJis); 

 or erect and cohering by their bases into an elongated tube (MamUlaria, Melocactus, 

 Echinocactus, Cereus, Epiphyllum). Stamens numerous, many-seriate, inserted at 

 the base of the corolla, the inner generally the smallest ; filaments filiform ; anthers 

 introrse, 2-celled, dehiscence longitudinal. Ovaey inferior, 1-celled ; placentas 

 parietal, 3 or more, bilamellate ; style simple, elongated, cylindric or pyramidal, 

 hollow or solid ; stigmas equal in number to the placentas, linear or loriform, 

 spreading or close ; ovules numerous, horizontal, anatropous. Beeet smooth or 

 furnished with spines or bristles (in the axils of which often spring branches), 

 umbilicate, 1-celled ; placentas parietal, pulpy. Seeds numerous, buried in the 

 pulp, globose or ampuUaceous ; testa nearly bony, black, shining, foveolate ; hilum 

 large, circular, pale ; albumen 0, or nearly so. Embexo sometimes straight, clavate 

 or sub-globose, sometimes curved or semicircular ; cotyledons free or united ; radicle 

 facing the hilum. 



[The following tribes are adopted in the ' Genera Plantarum ' : — 



Tribe I. Echinocacte^. — Oalyx-tnbe produced beyond the ovary. Sfcem covered with 

 elongate tubercles, or ribs whicli are aculeate, rarely leafy. *Melocactus, *Mamillaria, Leucli- 

 tenlergia, *BcMnooactus, *Gereus, *PhyUocactus, *Epiphyttu,m, &o. 



Teibe II. Opuwtie^.— Calyx-tube not produced beyond the ovary. Stem branched, 

 jointed. *BMpsalis, Nopala, *Opimtia, *PeresTcia. — Ed.] 



We tave indicated the afBnities of Caetece with Mesembryanthemea (which see). A. L. de Jussieu 

 placed Cactus and Riles in the same family ; and in fact there is a close affinity between them, founded 

 on the polypetalous and epigynous corolla and its sestivation, the one-celled ovary with parietal placenta- i 

 tion, the berried acid fruit, and the spiny cushion from the axil of which spring the leaves and flowers ; 

 but the habit of Cacti, the fleshy consistency 'of their stem, the indefinite number of their petals and 

 stamens, and their scanty albumen, render the diagnosis easy. 



