FAMILIES OF FLOWERING PLANTS 207 
4-5-parted corolla. The stamens are equal to, or a multiple of the lobes 
of the latter, and are hypogynous. The anthers are 2-celled, often 
tipped with a horn or appendage as in the blueberries. The ovary is 
2-5-celled, becoming in fruit a loculicidal or septicidal capsule, a berry 
or a drupe. 
In Europe and Africa, the heaths are among the most conspicuous 
plants, whole tracts being often covered with a single species. These 
belong to the genus Erica, which is not represented in the New World ; 
but £. cinerea and E. Tetralix have become sparingly naturalized on the 
island of Nantucket, along with the Scotch heather (Calluna vulgaris). 
Many South African forms of great beauty are seen in cultivation in 
European hot-houses. 
Fic. 179. An American Heath (Cussiope tetragona). After Britton and Brown, 
Ill. Fl. Northeast U. S. 
The azaleas and rhododendrons form another extensive group of 
ornamental plants. They are conspicuous and brilliant along the sum- 
mits of the higher Alleghenies and also in the Himalayas and Alps. The 
flowers exhibit a wide range of color, from the purest white to the deep- 
est crimson, and all shades of yellow and orange. Probably our most 
beautiful azalea is A. lutea, the flame azalea, with flowers of a dazzling 
flame color. In the same class of ornamental shrubs may be ranked the 
mountain-laurel (Kalmia), which often grows with the rhododendron ; its 
flowers are quite different, however, in structure. The ten stamens, when 
the corolla first opens, are bent back like bows, the anther sacs fitting 
in little depressions or pockets on the corolla lobes. The slightest 
touch at the bases of the sensitive filaments by some prowling insect in 
search of honey causes them to spring back, deluging the visitor with a 
shower of pollen and thus ensuring cross-fertilization. 
In the far northern regions and on the highest mountains the heaths 
seem to luxuriate, and many of the genera have their exclusive homes 
