Page:Popular Science Monthly Volume 31.djvu/100

90 of the student. To these two species add the wind-flower (Anemone nemorosa, L.), all of which appear at about the same time and in similar situations, and the student has three forms over which he may work for some hours before the representations of the three genera are satisfactorily determined. It is, however, just such work that opens the eyes of the young naturalist and makes him mindful of little things. The shepherd's-purse (Capsella Bursa-pastoris, Moench) is an intruder from Europe that has found its way into our cultivated ground, and become most ugly because so much in the way of other and better plants. This weed seems to be running a race to the seed-goal with some other of our plant-pests. During the present season strings were tied upon certain flower-stalks when their flowers were in bloom, and a record was kept of the time required for the maturing of the seed. The number of days varied from fourteen to seventeen. This is in striking contrast with the two long years of maturation required for the acorns of many species of oaks. The ubiquitous dandelion can, however, win the pennant for quick-seeding from the shepherd's-purse. It can reach the home-line when capsulla is only half-way round the track. But while a dandelion-plant, on an average, produces 1,720 seeds, the shepherd's-purse ripens 17,600, or more than ten to one! The same student has determined this year that these figures are low indeed when compared with those for the offspring of the purslane speedwell (Veronica peregrina, L.). This small plant began flowering on May 3d, and before six weeks were past it had produced 186,292 seeds. What some plants may lack in size and durability they make more than whole by wonderful powers of reproduction. The Dicentra cucullaria (DC.) is the interesting "Dutchman's breeches," with the heart-shaped corolla, much like its cultivated favorite sister, the Dicentra spectabilis (DC), better known as "bleeding-heart," with its long, gracefully bending stems, each bearing a dozen or more of rosy "hearts." Our early wild dicentra exceeds its cultured relative in delicacy and beauty of foliage and its strange-shaped flowers, which are, although smaller and less highly colored, not less interesting structurally. The visiting insect, intent upon securing the honey secreted at the base of the petals, must brush aside a close-fitting cap or hood before the pollen and the stigma may be touched. The two canals leading to the nectar are so constructed that the insect, usually a bee, in thrusting his proboscis into either, brings his body against the hood and, pushing it aside, dusts fresh pollen from some other flower upon the stigma. Before he leaves, new pollen is unintentionally secured by the insect for the fertilization of the next flower visited. The hood of the pendent blossom falls back to its accustomed place as soon as the bee retires, and again incloses the pistil and the six stamens situated close around it. When we remember that the stamens of a particular flower may mature before its stigma, it is easy to understand that the pollen of that flower, although placed close by the side of the stigma,