50 



ORGANOGRAPHY. 



monadelphous (Gr. monos, one ; adelphos, brotherhood). 

 If they are united into two sets, as in Dicentra, they are 

 diadelphous ; if in three sets, triadel- 

 phous ; and so on. When the anthers are 

 united into a tube, as iu the Composite 

 family (Sunflower, Dandelion, etc.), they 

 ^^^ are said to be syngenesious (Gr. syn, 



with ; genesis, birth). If a transverse section of the anther 

 be made (Fig. 116), two or four cavities, called cells, will 

 be seen, and these are filled with a yellow dust, which, oa 

 examination with the microscope, proves to be small, round 

 bodies, called pollen (Fig. 117). Each pollen grain has 

 two coats: the outer, thicker and often orna- 

 mented ; the inner, more delicate and elastic. 



62. The opening of the anther at maturity, 

 for the discharge of the pollen, is called dehis- 

 cence. This commonly takes place by a line 

 along the whole length of each cell (Fig. 118). 

 Sassafras, Barberry, etc., the opening is by a lid or valve 

 (Fig. 119). In the Azalea, Pyrola, etc., the pollen 

 escapes by a pore at the top of the anther (Fig. 120). As 

 regards the attachment of the anther to the filament, it 

 may be innate, or inserted by its base on the top of the 

 filament (as in Fig. 121) ; or adnate, when attached by 



one face its whole length 

 (Fig. 122). It is ver- 

 satile when inserted 

 near its middle point to 

 the top of the filament, 

 lis 119 120 121 122 123 so that it may swing 



Fig. 116. Transverse section of an anther. Fig. IIT. A pollen grain. Figs. 118- 

 120. Dehiscence of anthers : by splitting longitudinally ; by lids or valves ; bypores. 

 Figs. 121-123. Attachment of anthers: 121. Innate; 122. Adnate; 12a. Versatile. 



