The instances which I have given are mostly from plants familiar in our fields, our gardens, or our greenhouses. They are, I think, sufficient to make us pause before we conclude that all conspicuous flowers are fertilized by insect agency. It may be that Bacon's warning to attend as carefully to negative as to affirmative instances has been a little forgotten. Moreover, these instances seem to show that it would be a great error to suppose that all flowers are fertilized either by insects or by the wind; and it is probable that the more the subject is considered the more complex will the arrangements for fertilization be found to be. The agencies to which I have last referred exist, it will be observed, in beautiful and conspicuous flowers; and yet act independently of that beauty and that conspicuousness: so that in each instance these facts are, on the utilitarian theory, unexplained and residual phenomena. They, therefore, demand earnest inquiry. For the existence of a single residual phenomenon is notice to the inquirer that he has not got to the bottom of his subject; that his theory is either not the truth or not the whole truth. Do the facts justify us in concluding that insect fertilization is more beneficial to the plant than fertilization by the wind or any other agency? Do they afford any sufficient cause for that change from the one mode of fertilization to the other which has been suggested? The facts bearing on these questions are very remarkable; for, as we have already seen, many plants produce two kinds of blossom, the one conspicuous and the other inconspicuous; the one visited by insects, the other self-fertilizing. Recent observation shows that these cleistogamous flowers, as they are called, are present in a great variety of plants.[17] In the violet they are found to exist, being seen in the summer and autumn, when all the more brilliant flowers have gone. The one flower has everything in its favour--honey and a beauty of colour and of smell that has passed into a proverb--and it opens its blue wings to the visits of the insect tribe in the season of their utmost jollity and life. The other has everything against it: it is inconspicuous, scentless, ugly, and closed. And yet, which succeeds the better? which produces the more seed? The cleistogamous, and not the brilliant flowers: the victory is with ugliness, and not with beauty.