Class I. MONANDRIA, containing all plants of which the flowers have only one stamen; as the mare's tail. II. DIANDRIA: two stamens; as the jasmine. III. TRIANDRIA: three stamens; as wheat, oats, and grasses in general. IV. TETRANDRIA: four stamens; as woodruff. V. PENTANDRIA: five stamens; as the primrose. VI. HEXANDRIA: six stamens; as the lily and tulip. VII. HEPTANDRIA: seven stamens; as the horse-chestnut. VIII. OCTANDRIA: eight stamens; as the heaths. IX. ENNEANDRIA: nine stamens; as rhubarb. X. DECANDRIA: ten stamens; as the pink. In the next three classes, the stamens exceed ten in number, but differ from each other in certain circumstances. XI. DODECANDRIA: stamens from twelve to twenty; as in agrimony. XII. ICOSANDRIA: twenty or more stamens, inserted upon the inner side of the calyx; as in the rose and apple. XIII. POLYANDRIA: twenty or more stamens, inserted upon the receptacle or point of union of all the parts of the flower; as in the crowfoot and anemone. The relative length of the stamens determines the next two classes. XIV. DIDYNAMIA: four-stamens, of which two are shorter; as in thyme and foxglove. XV. TETRADYNAMIA: six stamens, of which two are shorter; as in cabbage and wallflower. Three classes are indicated by having the stamina connected by their filaments. XVI. MONADELPHIA: stamens united by their filaments into a single body or set; as in mallows. XVII. DIADELPHIA: stamens united into two distinct sets; as in fumitory. XVIII. POLYADELPHIA: stamens united into three or more bundles; as in hypericum and cistus. In the next class, the stamens are united by their anthers. XIX. SYNGENESIA: five stamens united by the anthers; as in the dandelion and violet. In the twentieth, the pistil and stamen are united. XX. GYNANDRIA: stamens united to the pistil; as in orchis. The plants of all the above classes have flowers furnished with both stamens and pistils; but in the next three the flowers are unisexual. XXI. MONOECIA: Flowers bearing stamens only, and flowers bearing pistils only, occurring on the same plant; as in the oak. XXII. DIOECIA: stameniferous flowers on one, and pistilliferous flowers on another individual of the same species; as in willows. XXIII. POLYGAMIA: Flowers bearing stamens and pistils, flowers bearing stamens only, and flowers bearing pistils only, all on the same individual, or on different individuals of the same species; as in the ash and pellitory. The above classes contain all the plants that are _Phoenogamous_, or have distinctly perceptible organs of reproduction; the next and last class is composed of the _cryptogamous_, or those of which the flowers either do not exist, or have not been demonstrated.