STAMENS. 69 



more numeroiis, this is owing to the development of one or 

 more additional whorls by dedoiiblement^ or unlining. Most 

 Endogenous plants have either three or six stamens, and the 

 number five or ten is most common in Endogenous plants. 

 The stamens arise from the receptacle {tarns) of the flower, be- 

 tween the base of the petals and the pistils. 



7T. Stamens are exterior wdth res23ect to the pistil, and int&- 

 rior with respect to the corolla. They exhibit a variety of 

 positions with respect to the pistil. If the stamens are in- 

 serted ujpon the pistil, as in umbelliferous plants, they are 

 said to be ejpigynoiis (from e])i^ upon, and gynia^ pistil) ; if the 

 stamens are inserted under the germ, as in cruciform plants, 

 they are said to be Tiyjyogynous (from hyjpo^ under, and gynia^ 

 pistil); when the stamens are inserted upon the calyx, and 

 thus stand around the germ, as in the rosaceous plants, they 

 are said to be ijerigynous (from jperi^ around, and gynia^ pis- 

 til). The normal position of stamens is below the pistil. 



When a corolla is monopetalous, the number of the stamens 

 is usually either equal, double, or half that of the divisions 

 of the corolla; the stamens in such flowers never exceed 

 twenty. In polypetalous corollas the number of stamens is 

 often greater. When they equal the divisions of the corolla, 

 they usually alternate with these divisions. When the num- 

 ber of stamens is double the divisions of the corolla, half of 

 the stamens are usually placed in the intervals of the divisions, 

 and the remaining half before each lobe of the corolla, cor- 

 responding to the intervals in the divisions of the calyx. If 

 any of the stamens are barren, or without anthers, they will 

 be found to be those which are placed before the lobes of 

 the corolla. Like the other parts of the flower, the stamens are 

 modified leaves, resembhng them in their structure, and like 

 them consisting of cellular and vascular tissue. They appear 

 at first as cellular projections, and are arranged in a spiral 

 form, unless the normal law be changed by circimistances. 

 They have a greater resemblance to petals than to leaves, and 

 we often see a gradual transition from j^etals to stamens. 



a. In commencing the analysis of flowers according to the Linnaean system, we 

 learned that the number of stamens, their position, relative length, and connectioih, 

 taken eitlier singly or in combination, afford certain and distinctive marks for pur- 

 poses of classification. 



In the first place we find the stamens differing in number, in different plants ; 

 some plants have but one, some two, and so on, till we come to ten ; when they 

 have more than ten, we find the number in the same plant varies, and therefore we 

 cannot depend on this circumstance for further classification. 



77. Position of the (sfamens with respect to the pistil — Divisions of monopetaloua corollas nsnally in 

 proportion to the number of stamens — Situation of the stamens with respect to the divisions of tlie 

 corolla— a. Stamecs used for purposes of classification. 



