MOEPHOLOGY OF EEPRODUCTIVE OEGANS 191 



necessarily lead to corresponding alterations in the mutual 

 relation of the different whorls of carpels which compose an 

 apocarpous pistil, and modify very materially the appearance 

 of different flowers. 



2. Syncarpous Pistil. — We have already seen, in speaking 

 of the floral envelopes and androeoium, that the different parts 

 of which these whorls are respectively composed may be distinct 

 from each other, or more or less united. From the position of 

 the carpels with respect to one another, and from their nature, 

 the latter are more frequently united tlian any other parts of the 

 flower. This union may take place either partially, or entirefy, 

 and it may commence at the summit, or at the base of the 



Fig. 407. 



FiGf. 408. 



¥ie. 40'J. 



/'ig'. 407. Central part of the flower of the Tiilip-tree {Liriodendrontulipiferd). 

 The thalamus, a, is more or less cylindrical, c, c. Carpels, c, e. Stamens. 

 Fig. 408. Section of the flower of the Strawberry. The thalamus is 

 nearly hemispherical, and bears a number of separate carpels on its upper 



portion. Fig. 409. Section of the ripe pistil of the RaspbeiTy, showing 



the conical thalamus, I. 



carpels. In the former case, as in Xamthoxylon fraxineiim 

 {fig. 411), the carpels are united bj' their stigmas only ; in Dic- 

 tamnus Fraxinella {fig. 427) the upper parts of their styles are 

 united ; while in the Labiatse {fig. 412, s), and most BoraginacejE 

 {fig. 413, d), the whole of the styles are united. In all these 

 oases the ovaries are distinct, and in many Boraginacese the 

 stigmas also ; but in all Labiatte the stigmas are distinct. 



It is far more common to find the carpels united by their 

 lower portions or ovaries, and this union may also take place to 

 various extents. Thus, in the Eue {fig. 414, ov), the union only 

 takes place at the base of the ovaries, the upper parts remaining 

 distinct, in which case the ovary is commonly described as 

 lobi'd. In Diantlius {fig. 405) the ovaries are completely 



