ANGIOSPERM.fi. 



417 



extent, to enormous trees, 50 to 100 metres high, and often 

 several or many centuries old. 



524. The flowers of the Angiosperms, while sometimes 

 so reduced as to be quite simple, are in all cases much more 

 complex than those of Gymnosperms. In most cases they 

 are monoclinous (hermaphrodite), i.e., the male and female 

 sexual organs occur in the same flower ; in such case each 

 flower consists essentially of an axis bearing one or more 

 pollen - producing organs 

 (anthers, Fig. 304, a), and 

 one or more ovule-contain- 

 ing organs (ovaries, Fig. 

 304, F). These are, when 

 more than one, generally 

 arranged upon the axis in 

 one or more Avhorls ; the 

 staminal whorls normally 

 arise below the ovaries. Be- 

 sides these essential organs, 

 there are usually secondary 

 or accessory organs, such as 

 the delicate, and frequent- 

 ly Colored floral leaves ( pet- Fig. ,m -Diagrammatic section of an an- 



als or sepals, JT and Ke, $?SZ^& a %^&%^ 

 Fig. 304), the honey glands, S 8 ^ p ^/r ^heovlry fXe' 



pj-p style, and n the stigma of the pistil the 



ovary contains one ovule, which has a single 



525 The axis Of the coa *' * enclosing the ovule body, S; em, the 

 embryo sac ; JS, germ cell or germinal vesi- 



flower (the TorUS or Re- cle .: pi, a pollen-tube penetrating the , style, 

 and reaching the germ-cell through the mi- 



ceptade), usually remains cropyle of the ovule.-After PraisS. 



very short, so that the different organs of the flower are 

 closely approximated, and thus distinctly set off from the 

 other parts of the plant. The axis is, moreover, but very 

 rarely prolonged beyond the flower, all growth ceasing in it 

 when the floral organs are developed. In most cases the re- 

 ceptacle is conical or hemispherical in shape ; in other cases 

 it develops into various shapes, the principal ones of which 

 will be noticed hereafter. 



526. The lower portion of the flower axis generally bears 

 one or moiv whorls of modified leaves (phyllomes), which 



