Both the white and the yellow sweet clover put their leaves to sleep at night in a remarkable manner: the three leaflets of each leaf twist through an angle of 90 degrees, until one edge of each vertical blade is uppermost. The two side leaflets, Darwin found, always tend to face the north with their upper surface, one facing north-northwest and the other north-northeast, while the terminal leaflet escapes the chilling of its sensitive upper surface through radiation by twisting to a vertical also, but bending to either east or west, until it comes in contact with the vertical upper surface of either of the side leaflets. Thus the upper surface of the terminal and of at least one of the side leaflets is sure to be well protected through the night; one is "left out in the cold." The dried branches of sweet clover will fill a room with delightful fragrance; but they will not drive away flies, nor protect woolens from the ravages of moths, as old women once taught us to believe. The ubiquitous WHITE or DUTCH CLOVER (Trifolium repens), whose creeping branches send up solitary round heads of white or pinkish flowers on erect, leafless stems, from May to December, in fields, open waste land, and cultivated places throughout our area, Europe, and Asia, devotes itself to wooing bees, since these are the only insects that effect cross-fertilization regularly, other visitors aiding it only occasionally. When nets are stretched over these flowers to exclude insects, only one-tenth the normal quantity of fertile seed is set. Therefore, for the bee's benefit, does each little floret conceal nectar in a tube so deep that small pilferers cannot reach it; but when a honeybee, for example, depresses the keel of the papilionaceous blossom, abundant reward awaits him in consideration of his services in transferring pollen. After the floret which he has been the means of fertilizing closes over its seed-vessel on his departure, it gradually withers, grows brown, and hangs downward, partly to indicate to the next bee that comes along which fords in the head still contain nectar, and which are done for; partly to hide the precious little vigorous green seed-pod in the center of each withered, papery corolla from the visitation of certain insects whose minute grubs destroy countless millions of the progeny of less careful plants. Thus the erect florets in a head stand awaiting their benefactors; those drooping around the outer edge are engaged in the most serious business of life. Sometimes a solitary old maid remains standing, looking anxiously for a lover, at the end of the season. Usually all the florets are then bent down around the stem in a brown and crumpled mass. But however successfully the clover guards its seeds from annihilation, its foliage is the favorite food of very many species of caterpillars and of all grazing cattle the world around. This is still another plant frequently miscalled shamrock. Good luck or bad attends the finding of the leaves,