STAMENS. 



91 



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

 show 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 

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

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



Fig. 216.— Stamens. 



1 Caiandrinia compressa. s Solanum Lycopersicum. ' Galanthua nivalis. < Cyclamen eiirepmum. ' Ramondia pyrenaica. 

 «,1 Cassia leiiitiva. s Pyrola rotundi/olia. ^ Arctostaphylos Uva-ursi. w Arctoslaphi.los aljnna. ti Vaceiiiium 

 uliginosum. 12 Pyrola unifiora. " Medinilla (after Baillon). » Vaccinium oxycoccus. i' Calceolaria Pamnii. 

 i« Tozzia alpina. ", " Sibbaldia procmnhens. » Galeopsis anyusti/olia. '-», " Erylhraea Centaurium. 2;, 28 Melissa 

 officinalis. ->, 25 Calla palustris. « Nyclandra (after Baillon). «', 2« Glol/ularia cordi/olia. 29, 8» Theobroma Cacao. 

 31 PiiKjuicula vulgaris. '- Garcinia. (All somewhat enlarged.) 



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

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

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

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

 two cavities. 



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



