Fig. 268. Head of flowers of a Coreopsis, divided lengthwise.
268. In Asters, Daisies, Sunflower, Coreopsis (Fig. [268]), and the like, only the marginal (or Ray) corollas are ligulate; the rest (those of the Disk) are regularly gamopetalous, tubular, and five-lobed at summit; but they are small and individually inconspicuous, only the ray-flowers making a show. In fact, those of Coreopsis and of Sunflower are simply for show, these ray-flowers being not only sterile, but neutral, that is, having neither stamens nor pistil. But in Asters, Daisies, Golden-rods, and the like, these ray-flowers are pistillate and fertile, serving therefore for seed-bearing as well as for show. Let it not be supposed that the show is useless. See Section [XIII].
Fig. 269. A slice of the preceding more enlarged, with one tubular perfect flower (a) left standing on the receptacle, with its bractlet or chaff (b), one ligulate and neutral ray-flower (cc) and part of another; dd, section of bracts or leaves of the involucre.
[269.] Adnation, or Consolidation, is the union of the members of parts belonging to different circles of the flower ([256]). It is of course understood that in this (as likewise in coalescence) the parts are not formed and then conjoined, but are produced in union. They are born united, as the term adnate implies. To illustrate this kind of union, take the accompanying series of flowers (Fig. [270]-[274]), shown in vertical section. In the first, Fig. [270], Flax-flower, there is no adnation; sepals, petals, and stamens, are free as well as distinct, being separately borne on the receptacle, one circle within or above the next; only the five pistils have their ovaries coalescent. In Fig. [271], a Cherry-flower, the petals and stamens are borne on the throat of the calyx-tube; that is, the sepals are coalescent into a cup, and the petals and stamens are adnate to the inner face of this; in other words, the sepals, petals, and stamens are all consolidated up to a certain height. In Fig. [272], a Purslane-flower, the same parts are adnate to or consolidated with the ovary up to its middle. In Fig. [273], a Hawthorn-flower, the consolidation has extended over the whole ovary; and petals and stamens are adnate to the calyx still further. In Fig. [274], a Cranberry-blossom, it is the same except that all the parts are free at the same height; all seem to arise from the top of the ovary.
270. In botanical description, to express tersely such differences in the relation of these organs to the pistil, they are said to be
Hypogynous (i. e. under the pistil) when they are all free, that is, not adnate to pistil nor connate with each other, as in Fig. [270].