[Illustration: Fig. 356. Longitudinal section of flower of Silene
Pennsylvanica, showing stipe between calyx and corolla.]
[Illustration: Fig. 357. Flower of a Cleome of the section Gynandropsis,
showing broadened receptacle to bear petals, lengthened stipe below the
stamens, and another between these and pistil.]
[Illustration: Fig. 358. Pistil of Geranium or Cranesbill.]
[Illustration: Fig. 359. The same, ripe, with the five carpels splitting
away from the long beak (carpophore), and hanging from its top by their
recurving styles.]
323. =The Torus= or Receptacle of the flower (237, Fig. 223) is the
portion which belongs to the stem or axis. In all preceding
illustrations it is small and short. But it sometimes lengthens,
sometimes thickens or variously enlarges, and takes on various forms.
Some of these have received special names, very few of which are in
common use. A lengthened portion of the receptacle is called
A STIPE. This name, which means simply a trunk or stalk, is used in
botany for various stalks, even for the leaf-stalk in Ferns. It is also
applied to the stalk or petiole of a carpel, in the rare cases when
there is any, as in Goldthread. Then it is technically distinguished as
a THECAPHORE. When there is a stalk, or lengthened internode of
receptacle, directly under a compound pistil, as in Stanleya and some
other Cruciferae, it is called a GYNOPHORE. When the stalk is developed
below the stamens, as in most species of Silene (Fig. 356), it has been
called an ANTHOPHORE or GONOPHORE. In Fig. 357 the torus is dilated
above the calyx where it bears the petals, then there is a long
internode (gonophore) between it and the stamens; then a shorter one
(gynophore) between these and the pistil.
324. =A Carpophore= is a prolongation of receptacle or axis between the
carpels and bearing them. Umbelliferous plants and Geranium (Fig. 358,
359) afford characteristic examples.
[Illustration: Fig. 360. Longitudinal section of a young strawberry,
enlarged.]
[Illustration: Fig. 361. Similar section of a young Rose-hip.]
[Illustration: Fig. 362. Enlarged and top-shaped receptacle of
Nelumbium, at maturity.]
325. Flowers with very numerous simple pistils generally have the
receptacle enlarged so as to give them room; sometimes becoming broad
and flat, as in the Flowering Raspberry, sometimes elongated, as in the
Blackberry, the Magnolia, etc. It is the receptacle in the Strawberry
(Fig. 360), much enlarged and pulpy when ripe, which forms the eatable
part of the fruit, and bears the small seed-like pistils on its surface.
In the Rose (Fig. 361), instead of being 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.]