THE WHITE LILY 



177 



in the spots on Lilium auratum, this is due to the 

 presence of red cell-sap. 



The groove at the base of each sepal or petal is 

 lined by a tissue of thin -walled cells, rich in 

 protoplasm, by which the nectar or honey is 

 secreted. 



The stamens require no detailed description, as 

 they have essentially the same structure as those of 



c.p.- 



FIG. 79. Division of the pollen mother-cell in a Lily. 



A, First division : n, n, daughter-nuclei ; e.p, granular 

 cell-plate, from which the new cell-wall will be formed. 



B, Second division : n, n, the four granddaughter-nuclei ; 

 c.p, c.p, the cell-plates from which the second cell-walls 

 will be formed. The four cells in B become the pollen- 

 grains. (After Strasburger.) Magnified 800. 



the Wallflower, though they are much larger. The 

 development, both of the stamen as a whole, and of 

 the anther with its four pollen-sacs, takes place in 

 the same way as in Dicotyledons. 



In each of the pollen-sacs there is a layer of tissue 

 (archesporium), which gives rise to a great mass of 

 pollen mother-cells. The division of a pollen mother- 

 cell to form its four pollen-grains, which takes place 



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