66 SCIENCE PRIMERS. [xv. 



White and various shades of yellow and red are found 

 in roses, tulips, and rhododendrons, but never blue. 

 Blue, yellow and white are found in gentians, but 

 very rarely red. Anemones are amongst the few plants 

 in the different kinds of which red, yellow, blue, and 

 white are found. Night-flowering plants have usually 

 large, white, very strong-scented corollas, on purpose 

 to attract moths. Certain lurid red or purple flowers 

 both look and smell like putrid meat, and hence 

 attract flies, which lay their eggs on them and fly away 

 with the pollen. 



98. Honey when secreted on the corolla is usually 

 at its very base (honeysuckle, crown-imperial), and to 

 reach it the insect has to disturb or brush against 

 the stamens, and hence carry away pollen. In the 

 grass of Parnassus, the honey is secreted in the tips 

 of the branches of an elegant comb-like scale opposite 

 each petal. The glands that secrete the honey are 

 called nectaries. 



FIG. 44. Honey glands of, , buttercup ; b y barberry ; both enlarged. 



XV. THE DISK. 



99. Usually at the base of the stamens and around 

 that of the ovary, there is a thickened ring of cellular 

 tissue, or a whorl of swellings, scales, or glands. It 

 very often secretes honey when the corolla does not, 



