COLORS OF NORTH AMERICAN FLOWERS 



of families, as the mustard and saxifrage families. The pur- 

 ple trillium and Dutchman's-pipe have brown or lurid-purple 

 hues. The custard-apple (Asinima triloba) is at first greenish 

 yellow, changing to dull purple. In most instances the brown 

 colors of flowers are due to a mixture of chlorophyll or carrotin 

 with anthocyanin. Among the brown flowers containing two 

 pigments are Carolina allspice (Calycanthus), the gooseberry, 

 wild ginger (Asarum), Adonis vernalis, and various orchids. 

 The black spots on the wings, or alae, of the bean (Vicia Faba) 

 contain an olive-brown pigment dissolved in the cell-sap. 

 The spots appear black because of the flat epidermal cells. 

 (Fig. 101.) 



THE COLORS OF NORTHERN APETALOUS FLOWERS 



257 



