TWENTY-THIBD ANNUAL MEETING. 79 



10 p. M Phyllocactus phyllanthns; closes before daylight to reopen for one 



or two times. 



10 to 11 P.M.. .Cereus grandiflorus; closes before morning. 



11 p. M Cereus speciosissimus ; wilts at 2 a. m. 



The above clock is the result of many years' observation; yet it is still subject 

 to some correction. Most of the plants in the above list are native in Kansas; a 

 few are introduced or cultivated, as Taraxacum dens-leonis, Portulaca grandiflora, 

 the mesembryanthemums, Mirabilis Jalapa, Datura metel, Ipomcea bona-nox, and 

 the last three cacti. 



In cases where a flower reopens for several successive days, it will be seen that 

 the stigmas and stamens are ready for action on different days. 



An idea has already been touched upon that is foreign to the subject of this 

 paper, namely, that night-blooming plants are always white or yellow; and on the 

 other hand, all blue, purple, and red flowers are day-blooming — not that all yellow 

 or white flowers are night-blooming, or that all day-blooming flowers are blue, pur- 

 ple, or red. 



Why are night-blooming flowers white or yellow? Isn't the reason for this very 

 clear? They can be distinctly seen for long distances by night-flying insects. 



It may be seen that many plants have preferences among the insects. For in- 

 stance: CEnothera missouriensis admits the cecropia moth only; no other moth has 

 a sucker long enough to reach the nectar, which is at a depth of nearly six inches; 

 and no other moth is so well adapted to perform the important office of fertiliza- 

 tion. CEnorthera grandiflora admits both cecropia and polyphemus moths; other 

 species of Oenothera are not so particular. Again, the red clover, with its large stores 

 of honey, does not admit the common honey-bee; so that that insect must confine 

 its labors to white clover or elsewhere. The red clover prefers the bumble-bee; and 

 the form of that insect is found to be best adapted to fertilization of that plant. 



So it may be found that every kind of flower has one or more particular kinds of 

 insect best adapted to it, and opens at the time of day only when such insects are 

 on the wing. 



One curious feature in this connection may be mentioned: The common prickly 

 pear (Opuntia missouriensis) conceals no nectar; but its stamens are not merely 

 sensitive — they are irritable to a high degree; and when an insect, attracted by the 

 sight and odor, alights upon the flower, the stamens immediately spring in upon 

 him from all around and cover him with pollen. Taken by surprise, he immediately 

 flies away, perhaps to another flower of the same kind, to be treated in the same 

 manner; but, in all probability, the prominent style of the prickly pear is ready to 

 receive the pollen, and quickly catches some of that which the insect has brought 

 with him from a neighbor. 



III. 



I now come to the third part of my paper, a certain series of motions in leaves, 

 tendrils, suckers, etc., depending upon the time of day or the requirements of the 

 plant. It goes without saying that the roots of a plant shoot downward and the 

 stem turns upward. That is, they do that as far as circumstances will admit. If a 

 plant start in a perpendicular bank the roots run into the bank and downward; the 

 stem outward and upward. 



If the plant be a twining vine, as soon as it has attained sufficient length, the 

 terminal bud commences to move around in a circle, the hop around to the right, 

 looking outward from the center, the morning glory to the left. As the vine grows 

 it increases gradually the circle in which it moves, until finally it touches something 



