eing convex or conical, the
receptacle is deeply concave, or urn-shaped. Indeed, a Rose-hip may be
likened to a strawberry turned inside out, like the finger of a glove
reversed, and the whole covered by the adherent tube of the calyx. The
calyx remains beneath in the strawberry.

326. In Nelumbium, of the Water-Lily family, the singular and greatly
enlarged receptacle is shaped like a top, and bears the small pistils
immersed in separate cavities of its flat upper surface (Fig. 362).

[Illustration: Fig. 363. Hypogynous disk in Orange.]

327. =A Disk= is an enlarged low receptacle or an outgrowth from it,
_hypogynous_ when underneath the pistil, as in Rue and the Orange (Fig.
363), and _perigynous_ when adnate to calyx-tube (as in Buckthorn, Fig.
364, 365), and Cherry (Fig. 271), or to both calyx-tube and ovary, as
in Hawthorn (Fig. 273). A flattened hypogynous disk, underlying the
ovary or ovaries, and from which they fall away at maturity, is
sometimes called a GYNOBASE, as in the Rue family. In some Borragineous
flowers, such as Houndstongue, the gynobase runs up in the centre
between the carpels into a carpophore. The so-called _epigynous_ disk
(or STYLOPODIUM) crowning the summit of the ovary in flowers of
Umbelliferae, etc., cannot be said to belong to the receptacle.

[Illustration: Fig. 364. Flower of a Buckthorn showing a conspicuous
perigynous disk.]

[Illustration: Fig. 365. Vertical section of same flower.]

Section XIII. FERTILIZATION.

328. The end of the flower is attained when the ovules become seeds. A
flower remains for a certain time (longer or shorter according to the
species) in _anthesis_, that is, in the proper state for the fulfilment
of this end. During anthesis, the ovules have to be fertilized by the
pollen; or at least some pollen has to reach the stigma, or in
gymnospermy the ovule itself, and to set up the peculiar growth upon its
moist and permeable tissue, which has for result the production of an
embryo in the ovules. By this the ovules are said to be _fertilized_.
The first step is _pollination_, or, so to say, the sowing of the proper
pollen upon the stigma, where it is to germinate.

Sec. 1. ADAPTATIONS FOR POLLINATION OF THE STIGMA.

329. These various and ever-interesting adaptations and processes are
illustrated in the "Botanical Text Book, Structural Botany," chap. VI.
sect. iv., also in a brief and simple way in "Botany for Young People,
How Plants Behave." S