The Linden family with about 35 genera and over 300 species is chiefly tropical, having more representatives in the southern than in the northern hemisphere. Of the 3 North American genera only one (Tilia) is arborescent. Of the 8 species of Tilia (pp. [197], [199]) found in North America 2 are native to West Virginia. The European Linden (Tilia Europea, L.) is occasionally planted.
ARALIACEAE—THE GINSENG FAMILY
This family having about 50 genera with over 400 species is chiefly tropical, though widely distributed in other parts of the world. The genus Aralia (page [201]) contains the only tree species in North America. This is common in West Virginia.
CORNACEAE—THE DOGWOOD FAMILY
The Dogwood family, with 15 genera, is widely distributed in temperate regions. Cornus (pp. [203], [205]) and Nyssa (page [207]) are the only genera having tree representatives in North America. Of the 40 known species of Cornus 15 are native to North America and 7 to West Virginia. The shrubby species are listed on page [234]. Nyssa comprises 7 known species, 5 of which are found in North America and 1 in this State.
ERICACEAE—THE HEATH FAMILY
The Heath family with its 90 genera and 1,400 species is widely distributed in tropical and temperate regions. Of the 40 genera found in the United States 7 have tree representatives. The flora of West Virginia comprises about 22 genera and 40 species belonging to this family. Many of these are shrubs, the names of which are given in the list of native shrubs beginning on page [232].