Jan., 1907.] Coloi- of Ohio Flowers. ' 57 



COLOR OF OHIO FLOWERS. 



Clara G. Mark. 



From earliest times the flowering plants have received a 

 great degree of attention, which no doubt is attributable for the 

 most part to their varied and often brilliant colors. There have 

 been manv curious beliefs and theories with regard to the color- 

 ing of flowers, both as to its cause and as to its significance. Of 

 these theories the one that has been most generally accepted in 

 modern times is that the color of flow^ers is a device to attract 

 animals, particularly insects, which may serve to carry pollen 

 from one flower or plant to another. That insects are sometimes 

 attracted by color has been proved ; but it has been demonstrated 

 that a color sense is almost wholly lacking except in the higher 

 insects, and when present has been developed in comparatively 

 recent times. This precludes the idea of color attraction in so far 

 as at least a part of the pollen-carrying insects are concerned, and 

 it gives weight to the probability that a majority of such insects 

 are attracted bv the form and odor of flowers rather than by their 

 color. It follows that while the attraction of pollen-carrying 

 insects may be in some cases one of the incidental results of the 

 coloring of flowers, it can hardly be said to be the primary pur- 

 pose of such coloring. The supposition at the present time is 

 that the purpose of the coloring in the flower is to increase the 

 temperature to a greater or less degree and so stimulate the activ- 

 ity of the protoplasm; also the colored parts of the flower may 

 serve as a screen to protect the more delicate reproductive parts 

 from the action of the direct rays of the sun. 



The two principal classes of pigments occurring in flowers 

 are the lipochromes and the anthocyans. The lipochromes vary 

 through the different tints of yellow, orange and dull red and 

 occur in the flowers as crystalloids. The anthocyans form a 

 series of substances varying from red to blue and violet and are 

 always found in solution in the cell sap. The color of a flower 

 may be due to the presence of one or both of these classes of 

 pigments. It has been found by experiments that flowers of 

 different colors show a marked difference in temperature when 

 exposed to the same conditions of light, moisture, etc. 



In studying the Ohio angiosperms with regard to the color- 

 ing of the flowers, they were first divided into two general groups: 

 First, those without typical floral parts, such as grasses and 

 sedges; second, those with typical floral parts. This second 

 group was again separated into two divisions: First, those in 

 which the flower or flower cluster is so large as to be conspicuous ; 

 second, those in wdiich the flower or flower cluster is incon- 

 spicuous. Record was kept in a general wav of the seasons of 



