GROSS ANATOMY OF THE ANQI08PEBMB. 309 



The stamens may be in a single wborl (monocyclic), in wticli case, 

 if agreeing in number witli the rest of the flower, the androecium is 

 said to be isostemonous ; they are often in two whorls {bicydie, Fig. 

 203), and when each whorl agrees with the numerical plan of the 

 flower, the androecium is diplostemonous. 



Union of Stamens — The various kinds of union require the use of 

 special terms. When there is a union of the filaments, the androe- 

 cium is 



Monadelphous, when the stamens are united into one set (Fig. S04) ; 



Diadelpfious, when united into two sets (Fig. 205) ; 



Triadelphous, when united into three sets, etc. (Fig. 206). 



When there is a union of the anthers, the androecium is syngenemua 

 or aynantherous. 



Adnation of Stamens — The stamens may be adnate to the petals, 

 when they are epipetalous ; in some cases they are adnate to the 

 style of the pistil, as in the Orchids ; such are said to be gynandrous. 



Structure of Stamens — Bach individual stamen is composed of 

 an anther, containing one or more pollen-sacs, borne upon a stalk 

 known as the yZtemerei. (Fig. 207.) 



The principal terms which designate the structural relation be- 

 tween the anther and the filament are : 



Adnate, applied to anthers which are adherent to the 

 upper or lower surface (anterior or posterior) of the fila- 

 ment ; when on the upper surface, the anthers are introrse ; 

 when on the lower, extrorse. 



Innate, applied to anthers which are attached laterally 

 to the upper end of the filament, one lobe being on one 

 side, the other on the opposite one. The part of the fila- 

 ment between the two anther-lobes is designated the con- 

 neciwe; it is subject to many modifications of form, and 

 often becomes separable by a joint at the base of the anther 



from the rest of the filament. //«■ ^- 



Stamen 

 Versatile is applied to anthers which are lightly attached enlarged. 



to the top of the filament, so as to swing easily ; these may ^en^-'^fc" 



also be introrse or extrorse. anther. 



THE GYNCECIUM. 



Numerical Terms- — The gynoecium is made up of one or more 

 carpels (carpids or carpophylls) — i.e., ovule-bearing phyllomes, and 

 it is said to be mono-, di-, tri-, tetra-,penta-, etc., a.nA poly-carpellary, 

 according as it has one, two, three, four, five, to many carpels. In 

 old books the terms monogynous, digynons, trigynous, etc., meaning 

 of one, two, three, etc., carpels, are used instead of the more desir- 

 able modern ones. When the carpels are more than one, they may 



