THE AMERICA X NATURALIST. [Vol. XXXVI L 



arntlca are blue. The closing of the flower in the afternoon 

 effects fertilization in the absence of insects. The species 

 of Lysimachia and Stejronema are yellow sometimes with a red 

 center, or dark spotted in Lysimack ia qu \ ' 

 tris. Of I. vulgaris there have been described three forms. 

 The smallest, which grows in the shade, has light yellow flowers 

 with greenish yellow filaments and is self-fertilized. The most 

 conspicuous and largest form grows in sunny localities, has dark 

 yellow petals with a red center and is rarely self -fertilized. The 

 third form is an intermediate one. The flowers of Lysimachia 

 are largely fertilized by bees of the genus Macropis. These 

 pollen flowers, which attract few visits, display white, yellow, red, 

 scarlet and blue colors, and the evidence is wholly insufficient 

 to prove that the coloring has been determined by the selective 



The species of Primula, well-known for the laborious investiga- 

 tions of Darwin, are largely dimorphous. The corolla is tubular 

 and the honey is deeply concealed. The flowers are yellow and 

 red. Bumblebees are frequent visitors to the yellow-flowered 

 forms, and Miiller found six red-flowered species in the Alps 

 fertilized by butterflies. On P. farinosa, which is red with a 

 yellow eye, he collected forty-eight Species of Lepidoptera. In 

 Glaux the corolla is wanting and the calyx is pink and petal-like. 



flowers of Primula acaulis. 



The Kbenales contain four families, the Sapotaceae, Ebena- 

 ceae, Symplocaceae, and Styraceae. There are but eight species 

 in the Northern States, two with yellow and six with white 

 flowers. In tropical regions these families are represented by a 

 large number of trees and shrubs of which the most important 

 is the ebony-tree, valued for its black heart wood. 



The characters of the Gentianales and Polemoniales are so sim- 

 ilar that the two orders cannot be readily distinguished. They 

 differ from the preceding families, which are more closely allied 

 to the Chqripetalae, in having but a single whorl of alternate 

 stamens, and in the smaller number of carpels. Up to this 

 point white and red colors have been most common in the Gam- 

 opetalous series, but these two orders are remarkable for con- 

 taining a large number of purple and blue flowers. 



