This family embraces 100 genera and about 1000 species, chiefly tropical in the Old World. Six genera of trees occur in North America. The genus Aesculus, (pp. 193, 195) comprises 14 species, 10 of which are found in America and 2 in West Virginia. No other genus of this family is represented in the flora of the State. The Horse Chestnut (Aesculus Hippocastanum, L.) is a common introduced species.