ORDER DIPENTAGYNIA. 
161 
names ; when they are of a round form, they are called Melon-thistles ; when more 
cylindrical and erect, Torch-thistles ; when creeping, with lateral flowers, Cereuses ; 
and when composed of a stem resembling flattened leaves. Prickly-pears. Plants 
of the Cactus tribe are mostly destitute of leaves, but the angular or flattened 
stems often appear like a series of thick, fleshy leaves, one growing from the top of 
another. The beautiful dye called cochineal is obtained from an insect of this name^ 
which feeds upon the Cactus cochinillifer. The Cactus opuntia, or true prickly 
pear, is found native in the United States.* In Brazil, some of the Cactus family have 
been known to attain the hight of thirty feet, with a circumference of three feet. 
226. The family Amygdalm comprehends the peach and 
almond, of the genus Amygdalus, with the plmxi, cherry, and 
pomegranate. Ihese, which were placed by Jussieu in his 
order Rosacese, or rose-like plants, seem very properly sepa- 
rated. The characteristics of this tribe are a calyx five-toothed, 
petals five ; stamens about twenty, situated on the calyx ; ovary 
superior, one-celled. The fruit a drupe. Trees or shrubs. The 
leav^es and kernel contain prussic or hydroGyanio acid. The 
genus Prunus contains the various kinds of the plum, cherry, 
and sloe; according to ancient writers it was brought from 
Syria into Greece, and from thence into Italy. We have sev- 
eral native species. The pomegranate (Punica) is a shrubby 
tree, a native of Spain, Italy, and Barbary ; it flowers from 
June till September. The Greek writers were acquainted with 
it, and we are told by Pliny that its fruit was sold in the 
neighborhood of Carthage. It is cultivated in England and 
the United States ; not for its fruit, which does not come to 
perfection so far north, but on account of its large and beauti- 
tul scarlet flowers, which render it an ornamental j^lant. At 
Fig. 142, is the flower of the pomegranate {Punica gramor 
turn) ; h represents the stamens of the same, as adhering to the 
calyx. The almond is a native of warm countries and seems 
to have been known from the remotest antiquity. 
227. Order Dijyentagynia. — Signifies two and five pistils. 
We find here the Pomacese {from pomum, apple), or apple tribe. 
This is included in Jussieu's Rosacese, or rose-like plants ; but 
although the flowers of the apple genus have a strong resem- 
blance to that of the rose, the difference in the fruit seems to 
render this division proper. In this tribe, the most important 
genus is Pyrus, which contains the apple and pear. The varie- 
ties of these fruits are the eflects of cultivation, not the prod- 
uce of diftert^nt species. By means of grafting, or inoculation, 
good fruit may be produced upon a tree which iDefore prod uced 
a poorer kind. Jussieu divided his natural order Kosacese 
into the following sections : Pomacem^ with fruit fleshy, like 
the apple and pear ; Posce^ having urn-form calyces ; Amygdor 
loB^ having drupe-like fruits. 
* For illustrations of this family, see Plate i., Figures 2, 5, and 7. 
22^3. Family Amygdalae — Prunus — Pomegranate — Amygdalus. — 227. Order Dipentagynia — Pora» 
tea- Varieties b>- grafting— Order Eosaceee divided into sections. 
