Ch. VI, 2] 



STRUCTURE OP FLOWERS 



275 



like, as in Iris (Fig. 199). The stigma, while frequently flat, 

 or rounded, is elongated variously, and even branched, some- 

 times to almost a feather-like degree, as in some trees (Fig. 

 197). The ovules, while typically few, are sometimes but one 

 to a carpel, though often they are many, as with Poppies, in 

 which case they stand in regular 

 masses or rows upon supporting 

 ridges, usually prominent, called 

 PLACENTiE. Unlike the other 

 parts, the pistils are not fleeting 

 but persistent structures, for, 

 after fertilization, the pistils 

 grow normally into fruits, and 

 the ovules into seeds ; at least 

 this is true of the ovaries, though 

 commonly the styles and stigmas 

 fall with the petals. While typ- 

 ically the pistil or pistils stand 

 on the receptacle separate from 

 the other parts, frequently the 

 other parts stand upon the ovary, 

 bringing the latter below and 

 outside of the showy part of 

 the flower, as with Apple and 

 Fuchsia ; and in this case the 

 ovary is described as inferior, 

 as contrasted with the ordinary 

 superior condition. 



Three other less prominent 

 parts appertain to flowers : the receptacle, nectaries, and 

 bracts. 



The receptacle is the tip of the floral stem, usually en- 

 larged to a club-shape where it bears the floral parts, though 

 sometimes it develops specialized forms, as will later be 

 noted in the section on morphology. Nectaries excrete, 

 often in shining drops, the nectar upon which insects feed. 



Fig. 188. — The structure of 

 a pollen grain, and germination 

 of the pollen tube, in Lilium 

 Martagon; X 200. 



A, ripe grain with its own vege- 

 tative nucleus, k, and a generative 

 cell, m, which produces the two 

 sperm nuclei ; B, the same grain, 

 in another view, about to germi- 

 nate ; C, the germinated grain 

 with its tube, the growth of which 

 is controlled by the nucleus k ; 

 D, end of the tube, with its two 

 sperm nuclei, formed from the cell 

 m, as it nears the egg cell. (From 

 Strasburger.) 



