. Beginners' botany. Botany. 142 BEGINNERS' BOTANY pearance of being one flower with a border of petals. Of such is the sunflower (Fig. 189), aster, bachelor's button or cornflower, and field daisy (Fig. 211). These long corolla- limbs are called rays. In some cultivated composites, all the florets may develop rays, as in the dahlia and chrysan- themum. In some species, as dandelion, all the florets naturally have rays. Syngenesious arrangement of an- thers is the most characteristic single feature of the composites. Double Flowers. —Under the stimulus of cultivation and increased food supply,
. Beginners' botany. Botany. 142 BEGINNERS' BOTANY pearance of being one flower with a border of petals. Of such is the sunflower (Fig. 189), aster, bachelor's button or cornflower, and field daisy (Fig. 211). These long corolla- limbs are called rays. In some cultivated composites, all the florets may develop rays, as in the dahlia and chrysan- themum. In some species, as dandelion, all the florets naturally have rays. Syngenesious arrangement of an- thers is the most characteristic single feature of the composites. Double Flowers. —Under the stimulus of cultivation and increased food supply, flowers tend to become double. True doubling arises in two ways, mor- phologically: {\)sta- mens or pistils may produce petals (Fig. 191) ; (2) adventi- tious or accessory petals may arise in the circle of petals. Both of these cate- gories may be pres- ent in the same flower. In the full double hollyhock the petals derived from the staminal col- umn are shorter and make a rosette in the center of the flower. In Fig. 192 is shown the doubling of a daffodil by the modification of stamens. Other modifications of flowers are sometimes known as doubling. For example, double dahlias, chrysanthemums, and sunflowers are forms in which the disk flowers have developed rays. The snow- ball is another case. In the wild snowball the external flowers of the cluster are large and sterile. In the culti-. Fig. 191. —Petals arising from the Stami- nal Column of Hollyhock, and accessory petals in the Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bailey, L. H. (Liberty Hyde), 1858-1954. New York, The Macmillan company
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