[Illustration: THE COFFEE TREE, SHOWING DETAILS OF FLOWERS AND FRUIT
From a drawing by Ch. Emonts in Jardin's _Le Caféier et Le Café_]
The next step in classification is to place the plant in the proper division under the sub-class, which is the order. Plants are separated into orders according to their varied characteristics. The coffee plant belongs to an order known as _Rubiales_. These orders are again divided into families. Coffee is placed in the family _Rubiaceæ_, or Madder Family, in which we find herbs, shrubs or trees, represented by a few American plants, such as bluets, or Quaker ladies, small blue spring flowers, common to open meadows in northern United States; and partridge berries (_Mitchella repens_).
The Madder Family has more foreign representatives than native genera, among which are _Coffea_, _Cinchona_, and _Ipecacuanha_ (_Uragoga_), all of which are of economic importance. The members of this family are noted for their action on the nervous system. Coffee, as is well known, contains an active principle known as caffein which acts as a stimulant to the nervous system and in small quantities is very beneficial. _Cinchona_ supplies us with quinine, while _Ipecacuanha_ produces ipecac, which is an emetic and purgative.
The families are divided into smaller sections known as genera, and to the genus _Coffea_ belongs the coffee plant. Under this genus _Coffea_ are several sub-genera, and to the sub-genus _Eucoffea_ belongs our common coffee, _Coffea arabica_. _Coffea arabica_ is the original or common Java coffee of commerce. The term "common" coffee may seem unnecessary, but there are many other species of coffee besides _arabica_. These species have not been described very frequently; because their native haunts are the tropics, and the tropics do not always offer favorable conditions for the study of their plants.
All botanists do not agree in their classification of the species and varieties of the _coffea_ genus. M.E. de Wildman, curator of the royal botanical gardens at Brussels, in his _Les Plantes Tropicales de Grande Culture_, says the systematic division of this interesting genus is far from finished; in fact, it may be said hardly to be begun.