238 .THE AMERICAN NATURALIST. | [Vor. XXXVI. 
coloration. C. florida is provided with an involucre that is 
usually white, but varies to pink or red. The fruit is scarlet 
and the leaves are bright red in autumn. 
SUMMARY. 
I. Throughout the Choripetale, with few exceptions, con- 
spicuousness is correlated with fertilization by insects. In the 
grape family the flowers depend upon their strong scent rather 
than upon bright coloring. In many genera it is possible to 
arrange the species in a progressive series, in which there is an 
advance from inconspicuousness, few. visitors, and self-fertiliza- 
tion, to many visitors, great conspicuousness, and the loss of 
thé power of self-fertilization. Pigments may be developed in 
all the organs of the inflorescence, as bracts, stems, sepals, 
petals, stamens, and pistils. 
2. The green flowers of the Polypetale are small, and the 
petals are frequently wanting. The white and yellow flowers 
vary from small to large, are the most common, and contrast 
more strongly with the foliage than purple or blue. Of the 
seventy-one polypetalous families, forty-three contain white, 
forty-one yellow, and twenty-nine both kinds of flowers. White 
flowers are most common in families or genera containing shrubs 
and trees, small flowers aggregated in a dense inflorescence, and 
nocturnal flowers. Dark nocturnal flowers are strongly scented, 
Yellow flowers are more commonly herbaceous and are most 
abundant in the same families as white flowers, unless the 
species are shrubs or trees. 
3. There is no evidence of the preference of beetles for 
flowers of any particular color. They do not avoid dull yellow. 
They are most common on small, white-clustered flowers with 
easily accessible honey and pollen. Diptera visit most frequently 
white and yellow flowers, but as they become more specialized 
and restrict themselves to flowers the percentage of visits to red 
and blue flowers increases. . They appear to find a parti-colored, 
mottled, or dotted inflorescence, as in the Cruciferae and Saxi- 
fragaceze, attractive. Carrion flies eru malodorous lurid- 
Pepe or r flesh-colored flowers. 
