INTRODUCTION TO BOTANY. XV 



the slit or opening foces the pistil ; extrorse, when the opening is towards 

 the cii'cumference of the flower. 



101. Very peculiar structxires of the anther and pollen will be descrihed 

 under the Orders AsclepiadecB and Orchidem. 



§ 12. TU Fistil. 



102. The Pistil or female system always occupies the centre of the 

 flower and terminates the growing axis. It consists of one or more carpels^ 

 containing the germs of one or more seeds. The pistil is usually sessile ; 

 if stalked, its stalk is called a podocarp (but this must not be confoiindcd 

 with the gynobasis or (lynophore) (127). 



103. A complete pistil consists of three parts : — 



1, the ovary or enlarged base, which includes a cavity or cell 



(Joculus), containing one or more ovules (117), which are the 

 earliest condition of the future seeds. 



2, the style, a prolongation of the carpel usually proceeding from 



the simimit, sometimes from the side of the ovary, and sup- 

 porting 



3, the stigma. This is various in appearance, sometimes a mere 



point to the style, sometimes a flattish cushion, sometimes a 

 narrow line, sometimes a broad lamina ; but it always consists 

 of loosely cellular substance, destitute of epidermis, and covered 

 with minute protuberances, called pajnllce. It is through the 

 stigniatic tissue that the fertilizing influence of the pollen is 

 conveyed to the ovules. 



104. The style is often wanting, and the stigma is then sessile, but in the 

 perfect pistil there is always at least one ovule in the ovary, and some 

 portion of stigmatic tissue. "Without lilese the pistil is imperfect, and said 

 to be barren, abortive, or rudimentary according to the degree of imper- 

 fection. 



105. The ovary being the essential part of a pistil, most of the terms 

 relating to the number, arrangement, etc., of the carpels apply specially to 

 the ovary. In general, the term ovary is used to designate all the carpels 

 of a flower, especially if they are at all united. 



106. The number of carpels or ovaries in a flower is frequently reduced 

 below that of the parts of the other floral whorls, even in flowers otherwise 

 symmetrical. In a comparatively small number of genera the carpels are 

 more numerous than the petals, or indefinite ; in these cases they are 

 either arranged in a single whorl, or form a head or spike in the centre of 

 the flower, as in the Buttercup and Anemone. 



107. The terms monogynous, digynous, etc., polygynous (1, 2, or many 

 ovaries) are vaguely used, applying sometimes to the whole pistil, some- 

 times to the carpels alone, and sometimes to the styles or stigmas. When 

 a more precise nomenclatm-e is used, the flower is monocarpellary, when the 

 pistil consists of a single, simple carpel ; hi-, tri-, etc., or polycarpellary, 

 when the pistil consists of 2, 3, or many carpels, whether separate or united. 



108. A pistil is syncarpous when the carpels are united into one com- 

 pound ovary ; apocarpous, when the carpels are free or separate. 



109. A compound ovary is, 



tuiilocular, or one-celled, when there are no partitions between the 

 ovtdes, or when the partitions do not meet, so as to divide the 

 cavity into several chambers. 



plurilocular, or several-celled, when completely divided into two or 

 more cells by partitions called dissepiments [septa). These 

 dissepiments are usually vertical, radiating from the centre or 

 axis of the ovary to its circumference. 



