/^HE casual observer may perhaps 

 have noticed that interesting law 

 of nature which governs the color- 

 ing of flowers, and which confines 

 the hues of a given flower, or per- 

 haps a botanical group of flowers, 

 to two colors and the combination of these col- 

 ors. The three primary colors — red, yellow, and 

 blue — are rarely to be seen in the blossoms of the 

 same botanical group. Thus we observe roses, 

 hollyhocks, chrysanthemums, and tulips in all 

 shades of white, yellow, pink, red, and crimson, 

 even almost approaching black, and numberless 

 combinations of these colors, but never blue. The 

 same is true with dahlias, zinnias, lilies, gladioli, 

 pinks, and portulacas. 



On the other hand, flowers which are notably 

 blue — as in the bellworts, or " Canterbury -bells," 



