CHAPTER V 



THE ANDROECIUM 



Review. — It has already been shown, in considering the general 

 nature of the flower, that in at least a large part of the flowering class, 

 the androecium typically consists of two stamen-circles, the stamens 

 of each isomerous with the parts of the other circles, one standing in 

 front of each petal and sepal, that each stamen is entirely free and 

 distinct, and of characteristic form and structure (Figs. 12 and 14). 

 We have also pointed out some of the forms of deviation due to 

 duphcation, suppression, adhesion, and metamorphosis. To these the 

 following general remarks may be added. 



Sterile Filaments and Anthers. — When an anther, still present, has 

 lost its function, it is called a Sterile or Imperfect Anther. When the 

 anther has become suppressed, but the filament remains, the latter is 

 called a Sterile Filament. Either of these is called a Staminodium. 

 One or more complete circles of sterile filaments, changed or not by 

 metamorphosis, may be mistaken for a crown or a disk (Fig. 38). 

 Adhesion of the stamens to the corolla, or even to the ovary, may 

 include only one circle, the other circle being entirely free, or they may 

 be adnate in different degrees (Fig. 44). 



Terms Indicating the Number of Stamens. — Before discussing other 

 and specific points of variation, we shall consider the typical organ 

 more in detail. The number of stamens in the androecium is indicated 

 by joining the appropriate numeral to the suffix "androus;" thus, 

 Monandrous, Diandrous, Triandrous, Tetrandrous, Pentandrous, etc. 

 These terms do not necessarily indicate the numerical plan of the flower. 

 When the number is 20 or more, the term Polyandrous or Stamens 

 Indefinite is commonly employed. 



Color. — In color, the filament is commonly white or whitish, and 

 the anther yellow; but this is not an absolute rule, as the latter is often 

 blue, brown, black, or otherwise coloi'ed. 



Construction of the Anther. — There are several distinct forms of attach- 

 ment of the anther to its filament which are characteristic of larger or 

 smaller groups. Its origin from the leaf assumes that each theca 

 corresponds to a vertical half of the leaf from which it has developed, 



