EXOGENOUS OK DICOTYLEDONOUS PLANTS. 



421 



veined leaves, usually in fascicles, often sprinkled with resinous dots. 

 Flowers in racemes or small clusters. Calyx-tube adherent to the 

 ■one-celled ovary, and more or less produced beyond it, five-lobed, 

 sometimes colored. Petals (small) and stamens five, inserted on 

 the calyx. Ovary with two parietal placentce : styles more or less 

 united. Fruit a many-seeded berry. Embryo minute, in hard 

 albumen. — Ex. Ribes (Gooseberry and Currant). Never unwhole- 

 some : the fruit usually esculent, containing a mucilaginous and sac- 

 charine pulp, with more or less malic or citric acid. Two or three 

 red-fiowered species of Oregon and California, and the Yellow or 

 Missouri Currant, are ornamental in cultivation. 



824. Ord. CactaCCiC {Cactus Family). Succulent shrubby plants, 

 peculiar in habit, with spinous buds, usually leafless : the stems 

 either globular and many- 

 angled, columnar with several 

 angles, or flattened and joint- 

 ed. Flowers usually large 

 and showy. Calyx of sev- 

 eral or numerous sepals, im- 

 bricated, coherent with and 

 crowning the one-celled ova- 

 ry, or covering its whole sur- 

 face ; the inner usually con- 

 founded with the indetinite 

 petals. Stamens indefinite, 

 with long filaments, cohering 

 with the base of the petals. 

 Styles united : stigmas and parietal placentae several. Fruit a 

 berry. Seeds numerous, with a curved or fleshy and rounded em- 

 bryo, and little or no albumen. — All American, the greater part 

 Mexican or on the borders of Mexico. The common Opuntia 

 (Prickly Pear) extends north to New England : its mucilaginous 

 fruit is eatable. So is the sweet red pulp of the huge Cereus gigan- 

 teus of Sonora and South California, which forms a singular tree, 

 forty or fifty feet high. Cereus grandiflorus is the magnificent 

 Night-blooming Cereus. 



825. Ord. Loasacea;. Herbs usually clothed with rigid or stinging 

 hairs ; leaves opposite or alternate, without stipules ; the flowers 

 showy. Calyx-tube adherent to the one-celled ovary; the limb 



FIG. 1 



Flower of Mamillaria csespitosa, of the Upper Missouri. 



36 



