184 FLOWERS 



Parts of the Pistil. The enlarged terminal part of the 

 pistil is the stigma. The stigma varies greatly in form, color, 

 size and structure. 



The style is the part of the pistil which extends from the 

 stigma to the ovary. 



The ovary is the hollow part of the pistil which bears the 

 ovules; the ovules are attached to the placenta or ovule- 

 bearing part of the ovary. Morphologically, placentae are 

 the margins of the carpellary leaves which are united and 

 turned inward, forming for each carpel two placenta?. The 

 placenta? are arranged in a number of ways; in syncarpous 

 pistils the chief forms are the parietal, central arid free 

 central placentas. 



In the parietal placentce the margins of the carpels meet 

 and turn inward slightly to form the placentae which bear 

 the ovules. In the central placentae the margins turn inward, 

 meet at the center of the ovary and form as many locules or 

 cavities as there are carpels. If this type of ovary is com- 

 posed of five carpels, there will be ten placentae and ten rows 

 of ovules arranged in five locules and separated by septa or 

 walls. In the central placentae the septa between the locules 

 do not develop. In an ovary of five carpels the ten rows of 

 ovules remain attached to the ten placentae at the center of 

 the ovary. In the free central placenta it is not attached to 

 the top of the ovary. 



Parts of the Ovule. The ovule of the higher plants consists 

 of the following parts : a stem or funiculus, which when it 

 adheres to the body of the ovule, as in the anatropous and 

 campylotropous types, is called a raphe; a chalaza or point 

 of origin of the integuments; two coats or integuments, con- 

 sisting of an outer coat or primine and an inner coat or 

 secundine; the micropyle or opening through the coats; the 

 nucellus or stored food which surrounds the macrospore. 

 The macrospore develops into the female gametophyte. 



