THE AMERICAN NATUR A LIST. [Vol. XXXVII. 



near each other in the same flower, or the epidermis may con- 

 tain blue cells beneath which in the mesophyll is a layer of red 

 cells, as in Viola odorata} Yellow chromoplasts and anthocyan 

 occurring together give scarlet hues. The shades of flowers 

 depend upon the density of the chromoplasts, and the number of 

 layers of pigment cells, and the character <»t" the epidermis. 



Green Flowers.— Qi the 223 green flowers classed as ento- 

 mophilous many have no petals, as fifteen spec ies of the Poly- 

 gonaceae and eight species belonging to the CarynphyHacea-. 

 also in several Rosacea, in Acer saccharinum and "Didiplis dian- 

 dm. Many are self-fertilized, as Triglochin and Scheuchzeria, 

 and the orchids llabcnarca hyberborca and Epipactis riridiflom, 

 and the small green flowers of Lechea and Pcnthoruui sedoides. 

 Some have the petals caduceous and depend upon their scent to 

 attract insects, as the Vitaceae. Many are visited by flies and 

 the smaller bees, as various Melanthaceas, the Smilaceae, the 

 Anacardiacea?, and the green flowers of the Asclepiad'acece. But 

 the green flowers of Asparagus are visited by the honeybee. As 



insects. & A transition stage is represented by the genus Rjbes. 

 which contains species with greenish, white, reddish, and yellow 

 flowers. As is well known many flowers pass through a green 

 stage before their bright colors appear. Large green flowers, 

 which are chiefly fragrant and nocturnal, are found in exotic 



