STAMENS. 



91 



fig. 214 ='). There are forms allied to this last-named plant in which the anthers 

 how very complicated convolutions— like those of the human brain. 



When the time draws near for the pollen to leave its place of origin, its cells 

 -whether in a loose powder or sticking one to another— become free from the 

 Qclosing wall of the anther, and lie embedded in the cavity of the pollen-sac, 

 .s it were in a purse or pocket, awaiting their release. The pollen-sac, hitherto 



Fig. 216.— Stamens. 



Calandrinia compressa. a Solanum Lycopersicum. » Oalantkus nivalis. * Cyclamen eur&poBum. 6 Ramondia pyrenaiea. 

 ', 1 Cassia lenitiva. » Pyrola rotundifolia. ' Arctostaphylos Uva-ursi. i» Arctostaphylos alpina. n Vamniwm 

 uliginosum. " Pyrola unifima. " Medinilla (after Baillon). " Vacdnium oxycoccus. " Calceolaria Pavonii. 

 i« Tozzia alpina. ^'^, 18 Sibbaldia procumbens. i* Galeopsis angusti/olia. 20^ 21 Erythrcea Centaurium. 22^ 28 Melissa 

 officinalis. 21 is Calla palustris. " Nyctandra (after Baillon). 27, aa Qlobularia cardifolia. 3», 80 Theobroma Cacao. 

 M Pinguicula vulgaris. »2 Qarcinia. (All somewhat enlarged.) 



osed, now opens, and the pollen is liberated. This opening or dehiscence of the 

 alien-sacs is accomplished in various ways. It has been already explained that 

 lost young anthers contain four sacs which rarely all remain distinct, but, by 

 le breaking down of the parti-walls between each pair, become merged into 

 v^o cavities. 

 These two cavities may be spoken of as anther-halves. In cases where the 



