FAMILIES OF FLOWEEING PLANTS 



207 



4-5-parted corolla. Tlie stamens are equal to, or a multiple of the lobes 

 of the latter, and are hypogynous. The anthers are 2-celled, often 

 tipped mth a horn or appendage as in the blueberries. The ovary is 

 2-5-celled, becoming in fruit a locuhcidal 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 E. cinerxa and E. TetraUxhave 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. 



Fig. 179. An Americau Heath {Cassiope tetragona). 



111. Fl. Northeast U. S. 



After Britton and Brown, 



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 



