LEADING FAMILIES OF FLOWERING PLANTS 363 



DICOTYLEDONS; SYMPETALOUS SUB-CLASS 



331. Families discussed. Five sympetalous families will here 

 be treated: the Heath family, the Mint family, the Nightshade 

 family, the Madder family, and the Composite family. Not 

 all of these families are of great 



economic importance (though two 

 of them are so), but they are among 

 the best representatives of sympet- 

 alous plants, the highest group 

 of the vegetable kingdom. 



332. The Heath family (Ericacea). 

 This family numbers over 1300 

 species, mostly of shrubs or under- 

 shrubs, widely distributed from the 

 polar regions to the tropical forests. 

 The flowers are hypogynous (Fig. 

 90) or else perigynous (not always 

 sympetalous) ; the anthers open by 

 pores or short slits. The fruit is a 

 capsule, a berry (often edible), or 

 a drupe with very small seeds. The 

 leaves are generally leathery and 

 evergreen, often small. 



333. Important plants of the 

 Heath family. Cranberries, blue- 

 berries, and huckleberries are highly 

 valued fruits of this family. Cran- 

 berries are borne by a delicate, 

 trailing, woody plant. The upland 



species is little used, but the ordinary large cranberry (Fig. 

 299), found in peat bogs all the way from North Carolina 

 to Minnesota and throughout a large part of Canada, is much 

 valued. The yield from uncultivated bogs is considerable ; 

 in Massachusetts, New Jersey, and Wisconsin cranberries are 

 extensively cultivated. 



FIG. 299. The common cran- 

 berry, not quite half natural size 



