398 



TREES AND SHRUBS. 



groups on the axis; each flower (Fig. 166, c) has a deeply 

 5- to 7-lobed " calyx " and from 5 to 12 stamens. The 

 female catkin has fewer flowers (1 to 5) ; each flower has 

 a shallow cup covered with triangular overlapping scales, 

 and inside this, the future acorn-cup, there is a 6-toothed 



BUD-SCALES 



STIGMAS-" 

 BRACT - 



Fig. 166. Oak. 

 A. Male ; B, Female inflorescences ; C, Male flower ; D, Female flower in section. 



"calyx" (Fig. 166, D, perianth) inserted above the small 

 ovary, which has a style with three stigmas. The ovary 

 has three chambers ; the ovules (two in each chamber) are 

 not even developed until after pollination. As a rule only 

 one seed is present in the ripe acorn ; still one often finds 

 three or more, especially in looking for seedlings. The seed 

 is filled up by the embryo, whose thick cotyledons contain 

 starch, together with tannin, oil, sugar, etc. (Art. 79). 



