xiv TERMS USED IN DESCRIBING THE FLOWER 187 



in the pistil will be three. The stigmas will, according to the 

 number present, be 2-fid, 3-fid, 4-fid, &c. They may be round, 

 square, feathery, or petaloid. When the style is absent the 

 stigmas are sessile. 



Placentation. The place where an ovule is fixed to the 

 ovary is known as the placenta, and the way in which they are 

 arranged and connected to the ovary by the placentas is called 

 placentation. The arrangement of the ovules in the ovary can 

 be determined by cutting across the ovary, and if it is small by 

 using a hand-lens to examine the section made. There are 

 several kinds of placentation, which are known as : 



Parietal Placentation, when the ovules are attached to the 

 walls of the ovary, as in the Poppy, Wallflower, and Pea. In 

 such an ovary there is generally one chamber, but in the Wall- 

 flower there are two. (Fig. P, 203). 



Axile Placentation, when the ovary is syncarpous, and the 

 carpels meet in the centre and from this longitudinal axis the 



P F A 



FIG. 203. P, parietal ; F, free-central ; A, axile placentation. (Diagrammatic.) 



ovules grow, as in the Daffodil, Hyacinth and Tulip. The ovary 

 generally possesses as many cells as there are carpels ; the 

 ovules are attached to the axis. (Fig. A, 203). 



Free-Central Placentation, when the ovary is one-chambered, 

 and the carpels form a swelling or column in the centre of the 

 ovary to which the ovules are fixed, as in the Primrose, 

 Stitchwort, and Chickweed. (Fig.F, 203). 



Basal Placentation, when the chamber of the ovary contains 

 only a single ovule and this springs from the base, as in the 

 Buttercup. 



Marginal Placentation, when in an ovary which is formed 

 from a single carpel the ovules are arranged along the ventral 

 margin, as in the Larkspur and Hellebore. 



Perianth. When the two outer whorls of the flower are 

 alike in colour and appearance it is called a perianth. The 



