84 



THE FLOWER 



gynfficium are directly concerned in the production of seed, as 



explained hereafter (Chap, xxii.), and are termed the essential 



parts of a flower. 



(i) The Androecium consists of stamens, each of which, as 



previously stated, is a modified form of leaf, although its 



appearance and structure is very different from the petals and 



sepals of the perianth. 



A stamen usually consists of a more or less elongated thread- 



hke portion — the filament — surmounted by a swollen thicker 



part termed the anther (Fig. 36). 



The anther consists of two somewhat elongated halves or 



anther-lobes {a), which are situated usually on opposite sides of the 



upper part of the filament : the 

 part of the filament uniting the 

 anther-lobes is termed the con- 

 nective (c). 



Running lengthwise in the 

 interior of each anther-lobe are 

 two chambers or hollow spaces 

 named pollen-sacs, within which 

 th& pollen is produced usually in 

 the form of loose round or oval 

 pollen-grains. In a young state 

 the latter are completely en- 

 FiG. 36.—^, A common form of stamen, closed in the auther-lobes, but 



y The filament ;« anther-lobe ; c the connec- • ■, . . ^ 



tive. B, View of stamen showing internal m a longer or Shorter time after 



structure. ^Filament ; c connective, on each .i • c ^^ n i 



side of which are the anther-lobes ; fs pollen tHe Opening Ot the HOWer the 



sacs, between which is a partition rf, when the „ ,i-,.; u t ii n 



anther is young ; on the right the anther-lobe PartltlOn between the pollcn- 



has dehisced, setting free the pollen-grains _„„„ ;_ ^,,„,,„„j „ j iU iv 



P ; e empty poiien-sac. sacs IS ruptured and the anther- 



lobes open by longitudinal slits 

 along the line of union of the two pollen-sacs {B, Fig. 36), the 

 pollen-grains being then set free in the form of dust-like powder. 

 In some cases the pollen-grains escape by pores or valve-like 

 openings situated near the apex of the anther. 



