190 



FAMILIES OF FLOWEEING PLANTS 



Western prickly ^^ax i^Opuntia huinifusa). 

 east U. S. 



After Britt. & Brown 111. Fl. North- 



Indica, which now occurs throughout Southern Europe, is the food plant 

 of the cochineal insect. Our own native Opuntias are highly ornamental 

 in the dry fields and rocky ledges when covered in early summer with a 

 mass of yellow flowers. The genus Echinocactus is noted for its very 

 formidable hooked spines ; while Cactus {Mamillaria), a genus in which 

 the plants are of small size and the flowers of bright colors, is particu- 

 larly desirable in pot cultivation. 



The order Myktiflorae, or Myrtales, may be known by the gamo- 

 sepalous calyx, the sepals being joined together, and by the compound 

 ovary, to which the calyx is usually adnate. There are 16 families, of 

 which the most important are the Thymelaeaceae, Lythraceae, Bhizo- 

 phoraceae, Combretaceae, Myrtaceae, Melastomaceae and Onagraceae. 



Family Geissolomaceae. Geissoloma Family. Consists of a single 

 genus, Geissoloma, confined to the Cape of Good Hope. They are low 

 shrubs of no particular interest. 



Family Penaeaceae. Consists of about 5 genera and 20 species, 

 also natives of South Africa. The parts of the flower are in fours, and 

 the ovary affords an exception to the usual rule in the order, in that it 

 is superior to, or free from, the calyx. 



Family Oliniaceae. Olinia Family. Another family with a single 

 genus, native of the same region. 



Family Thymelaeaceae. Mezereon Family. Shrubs or trees with 

 peculiarly tough inner bark. They have entire leaves, and flowers with 



