150 BOTANY. 
attached to the placentas by long thread-like funiculi ; spermoderm gelatinous _ 
externally ; albumen horny ; embryo straight, minute; radicle pointing to 
the hilum. Shrubs with alternate lobed leaves, having a plicate vernation. 
They are natives of temperate regions, and are found in Europe, Asia, and 
America. Many yield edible fruits, which sometimes contain malic acid. 
The various kinds of Gooseberry (Ribes grossularia), and Currant (Ribes 
rubrum and nigrum) belong to this order. It contains two or three genera, 
and nearly one hundred species. Examples: Ribes, Robsonia. The 
family is represented in North America by the genus Ribes with twenty- 
eight species. 
Orver 131. Cacracraz, the Cactus Family. Sepals numerous, usually 
», and confounded with the petals; adherent to the ovary. Petals numerous. — 
usually indefinite, sometimes irregular, inserted at the orifice of the calyx. 
Stamens indefinite, cohering more or less with the petals and sepals; 
filaments long, filiform; anthers ovate, versatile. Ovary fleshy, inferior, 
unilocular ; style filiform ; stigmas numerous; ovules ~, attached to parietal 
placentas equal in number to the stigmas. Fruit succulent, one-celled. 
Seeds ~, parietal, or, after losing their adhesion to the placenta, nestling in 
pulp, ovate or obovate; albumen 0; embryo straight, curved, or spiral ; 
cotyledons thick, leafy, sometimes nearly obsolete; radicle thick, obtuse, 
next the hilum. Succulent shrubs, with peculiar angular or flattened stems, 
having the woody matter often arranged in wedges. Leaves usually 
absent ; when present, fleshy, smooth, entire, or spinous. Flowers sessile, 
sometimes showy. They grow in hot, dry, and exposed places, and are 
natives chiefly of the tropical parts of America. Some grow rapidly on the 
lava in voleanic countries. There are, sixteen known genera, and about 
eight hundred species. Examples : *Opuntia, *Mammillaria, *Echinocactus, 
*Cereus, &c. These genera, with numerous species, represent the order in 
(extra-Mexican) North America. 
The plants of this order are remarkable for their succulence, for the great 
development of their cellular tissue, and for the anomalous forms of their 
stems, which sometimes are of great size. Opuntia vulgaris or prickly 
pear yields an agreeable fruit. The Night Blooming Cereus (Cereus 
grandiflorus) expands its large fragrant flowers only about ten p.m., which 
become withered before morning. 
Cereus hexagonus (pl. 69, fig. 3); 6, spines magnified. 
Orver 132. Ficoinrz or Mersempryantuace&, the Ficoid or Mesem- 
bryanthemum Family. Sepals definite, usually five, but varying from four to 
eight, more or less combined at the base, adherent to the ovary or distinct 
frem it, equal or unequal; estivation valvate or imbricate. Petals indefinite, 
colored, sometimes 0. Stamens perigynous, distinct, definite, or indefinite ; 
anthers oblong, incumbent. Ovary usually plurilocular; stigmas several, 
distinct; ovules 00, anatropal or amphitropal, attached by cords to the 
placenta, which is either central or parietal. Fruit a many-celled capsule, 
opening in a stellate or circumscissile manner at the apex, or an indehiscent 
nut. Seeds 00, rarely definite or even solitary ; embryo curved or spiral 
‘on the outside of mealy albumen; radicle next the hilum. Herbaceous o1 
150 
