686 POPULAR SCIENCE MONTHLY. 



His book, now a botanical classic, attracted but little attention ; his 

 publisher did not even send him a copy of it, and in disgust he turned 

 from the study of plants to that of languages. The title of the 

 work, The Secret of Nature in the Form and Fertilization of Flow- 

 ers Discovered, affords us the pleasure of knowing that he rightly 

 estimated the importance of his observations, Sprengel clearly 

 states that the bright hues of flowers, as is now well established, 

 serve as signals to attract the attention of nectar-loving insects flying 

 near by. He was led to this conclusion very fitly by the study of 

 Myosotis, the " forget-me-not." He has not been forgotten. His 

 name and theory were rescued from obscurity by Darwin; his book 

 a few years ago was reprinted at Leipsic, and is now universally rec- 

 ognized, says H. Miiller, as having " struck out a new path in botan- 

 ical science." 



A day's stroll through the fields and woodlands is sufficient to 

 show that yellow and white blossoms are in Nature more common 

 than red or blue. From an examination of 741 New England and 

 Eastern species belonging to 48 families (see table) it appears that 

 164 are yellow, 283 white, Tl red, 136 blue and purple, and 87 

 green. Greenish flowers occur in 25 families, yellow in 29, white 

 in 32, red in 16, purple and blue in 22. 



Yellow appears to have been the first color developed, and 

 flowers with this coloration are usually simple and regular in struc- 

 ture, as the buttercups and five-fingers. But why, it will be asked, 

 should yellow have been the primitive color? The spores and spore- 

 cases of the club mosses, and the pollen of all cone-bearing trees, 

 and, in fact, of most plants, are yellow, and the yellow coloration 

 of the first petals is doubtless correlated Avith this fact. Flowers 

 of this tint are peculiarly attractive to yellow-banded flies, and 

 when dull are avoided by beetles. Yellow flowers vary greatly in 

 size, but pale yellow flowers are usually small, and bright or orange- 

 yellow are large. Ranunculus ahortivus and R. sceleratus, which 

 grow in wet places, are small and pale, while R. bulhosus and R. acris, 

 the familiar buttercups of our meadows, are an inch broad. An 

 apparent exception to the above rule is offered by the globe-flower 

 {Trollius laxus), found in dense swamps, which has solitary, very 

 large, pale greenish-yellow flowers. As the cultivated European 

 and Asiatic species have bright yellow flowers, the coloring of the 

 sepals of T. laxus, for the petals are wanting, has probably retro- 

 graded from growing in dense shade. 



Yellow flowers in their natural state exhibit but little variation 

 of color. They change most readily to white, and less often to red 

 or blue. Under cultivation sudden variations from yellow to white 

 have been observed. A double yellow hollyhock, according to Dar- 



