182 FLOWERS 



Parts of the Stamen. The slender stem-like part of the 

 stamen is the filament; the enlarged apical part is the anther; 

 each anther has two anther sacs separated by a connective. 

 The anther sacs are sporangia bearing the pollen grains or 

 microspores, which upon germination develop into the male 

 gametophyte. 



The dehiscence or opening of the anther sacs to discharge 

 the spores is accomplished by sutures or splits in the surface, 

 as in yellow field lily; by pores, as in potato; or by valves, as 

 in sassafras. 



FIG. 112. Monadelphous stamens of marshmallow (Althaea officinalis). 



In members of the Composite there are usually five 

 stamens and they are syngenesious or united by their anthers 

 to form a tube. In mallow the stamens are united to form 

 a monadelphous or single group of stamens. In sweet pea 

 there are ten stamens of which nine are connate and form 

 one group, leaving a solitary stamen; stamens so grouped 

 are diadelphous. 



Number of Stamens. The number of stamens occurring 

 in the flowers of representative genera of plants is extremely 

 variable. A flower with one stamen is monandrcus; one with 

 two stamens is diandrous; one with three, triandrous, one 

 with four, tetrandrous; and one with five stamens is pentan- 

 drous. If the stamens are very numerous they are said to 

 be indefinite. 



