We must then look at all flowers as expressions of welcome to some insect--day-flowering blossoms mostly to bees and butterflies, and night-bloomers to moths. And not only expressions of welcome, but each with some perfect little plan of its own to make this insect guest the bearer of its pollen to the stigma of another flower of the same species. And how endless are the plans and devices to insure this beautiful scheme! Some flowers make it certain by keeping the stigma closed tight until all its pollen is shed; others place the anther so far away from the stigma as to make pollen contact impossible; others actually imprison these pollen-bringing insects until they can send them away with fresh pollen all over their bodies. Take almost any flower we chance to meet, and it will show us a mystery of form which the insect alone can explain. Here is one, growing just outside my door--a blossom "known" even to every child, and certainly to every reader of the "Round Table"--the pretty bluets, or Houstonia, whose galaxy of white or blue stars tints whole spring meadows like a light snowfall. We have "known" it all our lives. Perhaps we may have chanced to observe that the flowers are not all constructed alike, but the chances are that we have _seen_ them _all our lives_ without discovering this fact. If we pluck a few from this dense cluster beside the path, we observe that the throat of each is swollen larger than the tube beneath, and is almost closed by four tiny yellow anthers (Fig. 1). The next and the next clump may show us similar flowers; but after a little search we are sure of finding a cluster in which a new form appears, as shown in Fig. 2, in which the anthers at the opening are missing, and their place supplied with a little forked stigma! The tube below is larger than the first flower for about two-thirds its length, when it suddenly contracts, and if we cut it open we find the four anthers secreted near the wide base of the tube. What does it mean, this riddle of the bluets? For hundreds of years it puzzled the early botanists, only finally to be solved by Darwin. This is simply the little plan which the Houstonia has perfected to insure its cross-fertilization by an insect, to compel an insect to carry its pollen from one flower and deposit it upon the stigma of another. Once realizing this as the secret, we can readily see how perfectly the intention is fulfilled.