Fig. 46. A spike, the individual flowers attached directly to the common stalk. Fig. 47. A raceme, a spikelike cluster where individual flowers are stalked. Fig. 48. An umbel, the individual flower stalks all arising from one point. Fig. 49. Individual flower stalks of different lengths but the cluster usually flat-topped (corymb). Fig. 50. A flower cluster in which the end of the stem is terminated by a flower from the base of which side branchlets similarly tipped with flowers arise (cyme).
While highly irregular flowers are common in nature, conspicuous examples being the orchids in any florist’s window, or the milkweeds along the roadside, they can nearly always be seen to have various changes in the shape of their petals, or sepals, or stamens, or pistils, which are adaptations to their mode of life, but which always result in fertilization. Some plants, true monstrosities of nature, are not only far from having the usual arrangement of flower parts, but they even produce increased numbers of one part at the expense of others.
Double buttercups, and hundreds of our most beautiful garden blossoms, have been rescued by cultivation or the arts of the gardeners. Some roses seem to be practically all petals, but for every increase of petals there must be a decrease of some other part of the flower, and more often than enough it is the stamens and pistils that lose out in this transformation. Just as there is a decrease almost to the vanishing point in the birthrate when people become too effete and cultivated, so in plants there seems to be a point beyond which they cannot be pushed without suffering partial or often complete inability to produce young. The more highly they have been developed, oftentimes the greater their beauty, the less able are they to see to it that the chief function of flowers is accomplished. Such garden plants are increased by root division, cuttings and other arts of the gardener. Naturally true double flowers are almost unknown in wild plants, and the habit seems to have been brought about by too easy a time of it, too little struggle, too much food, or by any other of those things that produce effete but beautiful things, charming in their way, but of no significance in the sturdy struggle for existence that all wild plants must meet or perish. Another curious modification of a flower bud is cauliflower. Here the bud has been so developed, its calyx, sepals, etc., so transformed that the large, cabbagelike head, produced at the apex of the main stem of the plant, has by so much lost all semblance of a flower that it is actually a vegetable.