376 THE AMERICAN NATURALIST. [Vol. XXXVII. 



which change from red-purple to bright blue. Symphytum 

 officinale has a yellowish-white corolla, which is rarely purplish. 

 liomgo officinalis has a bright blue corolla, with which the black 

 cone of anthers offers a marked contrast. The last three species 

 are fertilized chiefly by bees. To this family belongs A media 

 comuta. When the flowers open each of the five petals is 

 marked with a dark purple spot, which by the third day has 

 faded entirely away leaving the corolla bright yellow. In the 

 Boraginaceaj, it is evident, that yellow and white are more prim- 

 itive than red, purple, or blue. A change in the cell sap from 

 an acid to an alkaline condition explains the coloration of flowers, 

 which are at first red but afterwards blue. The transition from 

 yellow to blue may be caused by the development of a soluble 



The species of Boraginaceae are very rich in anthocyan. The 

 roots and in some instances the leaves and stems, as in Echium 

 and Lithospermum, stain violet the herbarium paper on which 

 they are mounted. From the roots of L. canescens (puccoon) 

 the Indians derive a red dye. Another species of this family 

 Alkanna tinctoria (alkanet) is extensively cultivated in Kurope 

 for its carmine dye used in coloring silk and cotton fabrics, and 

 also oils, wax and wine. In the sheep pastures of New Mexico 



blood purslane, " when ^he sheep find a patch of it, it colors 

 their heads red clear to the ears." 1 



The flowers of the Yerbenaceae are two-lipped. Of the 12 

 northern species, two are white, two purple and eight blue. The 

 species present various interesting color changes and combina- 

 tions of colors. The native species of Verbena are white, pur- 

 ple, or blue. The cultivated varieties are remarkable for their 

 brilliant scarlet and crimson colors. Lantana mixta from Brazil 

 has flowers, which at first are white changing to yellow, orange 

 1 1 h 11 x t red. According to Fritz Miiller, the flowers when 

 yellow are sought by bees, and when red by butterflies. L. nivea 

 has sweet-scented white flowers, which in the variety L\muta- 



