CHAPTER X. 



THE STAMENS. 



Androecium The Stamen a foliar organ Filament; Anther and 

 Pollen Transitions of leaves to stamens Metamorphosis of 

 stamens Insertion, structure, &c., of stamen Anther-lobes, 

 Connective and Theca Filament and appendages Anther 

 and appendages, &c. Adnate, versatile, basifixed and dorsifixed 

 anthers Introrse and extrorse anthers Porous, valvular and 

 sutural dehiscence Branched stamens Numbers of stamens 

 Monadelphous, Diadelphous, &c. Syngenesious and Gynandrous 

 Hypogynous, Perigynous and Epigynous stamens Epipetaly 

 and Antipetaly Pollen Structure, shapes and sizes of pollen- 

 grain Pollinia. 



THE technical collective name for the whole of the stamens 

 in a flower is the Androecium, each stamen being itself a 

 specially modified foliar organ, adapted for the develop- 

 ment of pollen. The exceptions to this are rare, but in a 

 few plants with which we are not directly concerned here 

 e.g. Naias, Callitriche, and Casuarina the history of 

 their development shows that the staminal organs are part 

 of the axis. 



A typical stamen consists of two parts, the filament, or 

 stalk, and the anther, a two- or four-chambered stouter 

 portion which opens by slits or pores and discharges the 

 usually yellow dust-like pollen formed in the cavities. 

 The chambers are called pollen-sacs. 



The foliar nature of the stamen can be more or less 



