340 TEE POPULAR SCIENCE MONTHLY. 



common yellow ragwort, or in the daisy and the sunflower, have been 

 flattened out into long rays, which serve as pennants or banners to 

 catch the insect eye. They are very successful flowers, perhaps the 

 most successful family on the whole earth. But the groundsel, for 

 some reason of its own, has reversed the general family policy. It is 

 rarely visited by insects, and has, therefore, apparently taken once 

 more to self-fertilization ; and a complete alteration has thus been 

 effected in its appearance, when compared with its sister composites. 

 Though it has not yet quite lost its yellow center blossoms, it has no 

 rays, and its bells are almost concealed by its large and ugly green 

 involucre. Altogether, we may say that groundsel is a composite far 

 advanced on its way to a complete loss of the characteristic composite 

 habits. It still receives the visits of a very few stray insects ; but it 

 does not lay itself out to court them, and it is, probably, gradually 

 losing more and more of its winged clients from day to day. Thus 

 we see that any flower which will benefit by insect-fertilization, 

 whether it be a monocotyledon or a dicotyledon, high up or low down 

 in either series, is almost sure to acquire brilliant petals ; while, on 

 the other hand, any flower which gives up the habit of relying upon 

 insects is almost sure to lose or minimize its petals once more, and 

 return to a state resembling in general type the catkins and grasses 

 or the still lowlier self-fertilized types. 



The same sort of conclusion is forced upon us if we look at the 

 various organs in each flower which display the brilliant pigments. 

 The petals are most commonly the seat of the attractive coloration, as 

 in the dog-rose and the marsh-mallow. But in many other flowers, 

 like the fuchsia, the calyx is also beautifully colored, so as to aid in 

 the general display. In the tulips and other lilies, the crocus, the iris, 

 and the daffodil, sepals and petals are all colored alike. In marvel-of- 

 Peru and purple clematis, the petals are wholly wanting. In the com- 

 mon meadow-rue, it is the essential floral organs themselves which act 

 as allurements ; while, in the mesembryanthemums, the outer stamens 

 become flattened and petal-like, so as to resemble the corolla of other 

 flowers. In the composites, like daisies, where many blossoms are 

 crowded on one head, the outer row of blossoms is often similarly 

 flattened into rays which only serve the purpose of attracting insects 

 toward the fertile flowers of the center. Nor does the coloring pro- 

 cess stop at the regular parts of the flower alone: the neighboring 

 bracts and leaves are often even more beautifully tinted than the flow- 

 ers themselves. In the great white arums, grown in windows as 

 Ethiopian lilies, the actual blossoms lie right inside the big sheath or 

 spathe, and cluster round the tall yellow spike or spadix in the center : 

 and this sheath acts the part of petals in the more ordinary flowers. 

 Many euphorbias have very inconspicuous little blossoms, but each 

 small colony is surrounded by a scarlet involucre which makes them 

 some of the gayest among our hot-house plants. The poinsettia, 



