INTRODUCTION TO BOTANY.

Class XVII.—DIA DELPHI A.

The flowers of the plants of this class are all of the same form, fromthe common Pea to the smallest species of Trefoil.

The stamens are in two sets, ill general nine in one set, and oneonly in the other, which in most flowers is easily distinguished: in-deed, the form of the flower is sufficient to show the class. Thecommon Garden Pea {Pimm) is a good example of this class.

Class XV1IL—POLYDELPHIA.The eighteenth class is distinguished by the plants belonging to ithaving flowers with stamens in distinct sets. This class does not con-tain many plants ; and this is, on the whole, a fortunate circumstance,as the division of the stamens into several sets, which is the essentialcharacter, is not always to be distinguished. The Hypericum (St. John'sWort) is an example of this class.

Class XIX—SYNGENESIA.The nineteenth class contains plants bearing flowers which are term-ed compound, and which have many distinct florets on one com-mon receptacle. This is the most difficult class for the student atfirst to understand, as the parts are for the most part small, andthere is a singular coalescence of the stamens, which, with the cir-cumstance of some florets being imperfect, renders it necessary that heshould make himself acquainted with the other classes first, which willdoubtless lead to a more perfect knowledge of this.

Class XX.— GYNANDRIA.The twentieth is also difficult in some flowers, as the characteris formed from the stamens growing on a part of the style.

Class XXL—MONOECIA.The twenty-first class is composed of plants having flowers that bearstamens and pistils in distinct flowers but on the same root, as isseen in the Cucumber, Hazel, Willow, &.c.

Class XXIL—DIOECIA.The twenty-second class has the flowers producing stamens on one