Self-fertilization in its strictest sense occurs within the individual flower. Plants only resort to it as an extreme measure and commonly make use of many devices to prevent it. In the Iris, the petal-like stamens are in direct contact with the pistil and yet self-fertilization does not result, because the pollen surface is always carefully turned away from the ovary. By bringing their pistils and stamens to maturity at different times, many flowers make sure that they will not fertilize themselves. Such is the case in the Bulbous Buttercup and the Arrowhead. Flowers of the same tree or bush might be called distant cousins. Their union results in healthy offspring, though the marriage of still more divergent individuals is preferable. Plants like the Begonia, which bear single-sex flowers, often grow in somewhat isolated positions and so must intermarry a great deal among themselves. Staminate flowers at the top of a stalk can shower pollen over many female flowers growing below them. The exception always proves the rule, which explains why we find a few flowers which deliberately choose to fertilize themselves. In the Fuchsia, the flower droops, throwing the long pistil below the stamens, which can readily drop pollen onto it. Minute hooks hold the petals of the Indigo and Lucerne partly closed until the flower is completely developed. When they give way, the petals fly back, so shaking the whole flower that the anthers shower pollen on the pistil. The single-sex flowers of the Aloe bend near each other at mating time. The Violets and Polygalas are also largely self-fertilizing. They are, therefore, borne under the leaves or close to the ground, where they attract little attention. The love and marriages in plantdom may seem to be largely instinctive and mechanical, but that is probably because we have not investigated them sufficiently. The Persian poet Osmai believed that the plants had affairs of the heart as real as those recorded in the human world. Here is his account of one:-- “I was possessor of a garden in which was a Palm Tree, which had every year produced abundance of fruit; but two seasons having passed away without its affording any, I sent for a person well acquainted with the culture of Palm Trees, to discover for me the cause of the failure. “‘An unhappy attachment,’ observed the man, after a moment’s inspection, ‘is the sole cause why this Palm Tree produces no fruit.’ “He then climbed up the trunk, and looking around, discovered another Palm at no great distance, which he recognized as the object of my unhappy tree’s affection; and he advised me to procure some of the powder from its blossoms and to scatter it over the branches. This I did; and the consequence was my Date Palm, whom unrequited love had kept barren, bore me an abundant harvest.” [Illustration: FLORAL OFFERINGS IN A MOUNTAIN CATHEDRAL] CHAPTER VII ART IN THE PLANT WORLD