112 



PKACTICAL BOTANY 



the same thing, but in flowers with two or more carpels, each 

 carpel is one of the units of which the pistil consists. A one- 

 carpeled pistil is simple (Fig. 14), a several- 

 carpeled pistil is compound (Figs. 102, A, and 

 104, A). The parts usually found in a pistil 

 (Fig. 101) are the ovary, or enlarged ovule- 

 bearing portion, and the style or stalk, on which 

 is borne the stigma, which is usually expanded, 

 knob-like, or ridged, and with a rough moist 

 surface. When there is no style the stigma is 

 said to be sessile, and the stigma is borne on 

 the ovary. 



A compound pistil may consist of many 

 separate carpels, as in the stonecrop (Fig. 92), 

 strawberry, and buttercup. Frequently the 

 carpels are more or less completely united 

 (Figs. 102, A, and 295). The ovary of a com- 

 pound pistil may be formed of the united 

 ovaries of the carpels, or a considerable part 

 of the ovary may consist of a cup-like or 

 tubular growth beneath the carpels. 

 103. Locules of the ovary; placentas. Compound ovaries 

 sometimes have but one ovule-bearing cavity, but more gener- 

 ally they consist of several separate chambers, known as loc- 

 ules (Latin, loculi," little compartments"). They are then said 

 to be unilocular, bi- 

 locular, trilocular, 

 and so on. 



Ovules are not 

 borne by all parts 

 of the interior of 

 the ovary, but are 

 usually produced 

 only along cer- 

 tain regions. The 

 ridge, column, or 



ovary 



FIG. 101. A pistil, 

 with the ovary cut 

 through lengthwise 



stig, the stigma 



B 



FIG. 102. Three modes of bearing ovules 



A, ovary three-loculed, with the ovules borne on the 

 axis (central placenta) formed by the united partitions ; 

 .B, ovary one-loculed, ovules borne on the ovary wall 

 along three placentas; C, ovary one-loculed, ovules 

 borne on a/ree central placenta. After Behrens 



