les in their growth develop in three
or four different ways and thereby are distinguished into

_Orthotropous_ or _Straight_, those which develop without curving or
turning, as in Fig. 344. The chalaza is at the insertion or base, the
foramen or orifice is at the apex. This is the simplest, but the least
common kind of ovule.

_Campylotropous_ or _Incurved_, in which, by the greater growth of one
side, the ovule curves into a kidney-shaped outline, so bringing the
orifice down close to the base or chalaza; as in Fig. 345.

_Amphitropous_ or _Half Inverted_, Fig. 346. Here the forming ovule,
instead of curving perceptibly, keeps its axis nearly straight, and, as
it grows, turns round upon its base so far as to become transverse to
its funiculus, and adnate to its upper part for some distance. Therefore
in this case the attachment of the funiculus or stalk is about the
middle, the chalaza is at one end, the orifice at the other.

[Illustration: Fig. 348-350. Three early stages in the growth of ovule
of a Magnolia, showing the forming outer and inner coats which even in
the later figure have not yet completely enclosed the nucleus; 351,
further advanced, and 352, completely anatropous ovule.]

[Illustration: Fig. 353. Longitudinal section, and 354, transverse
section of 352.]

[Illustration: Fig. 355. Same as 353, enlarged showing the parts in
section: _a_, outer coat; _b_, inner coat; _c_, nucleus; _d_, rhaphe.]

_Anatropous_ or _Inverted_, as in Fig. 347, the commonest kind, so
called because in its growth it has as it were turned over upon its
stalk, to which it has continued adnate. The organic base, or chalaza,
thus becomes the apparent summit, and the orifice is at the base, by
the side of the hilum or place of attachment. The adnate portion of the
funiculus, which appears as a ridge or cord extending from the hilum to
the chalaza, and which distinguishes this kind of ovule, is called the
RHAPHE. The amphitropous ovule (Fig. 346) has a short or incomplete
rhaphe.

322. Fig. 348-352 show the stages through which an ovule becomes
anatropous in the course of its growth. The annexed two figures are
sections of such an ovule at maturity; and Fig. 355 is Fig. 353
enlarged, with the parts lettered.

Section XII. MODIFICATIONS OF THE RECEPTACLE.

[Illustration: Fig. 356. Longitudinal section of flower of Silene
Pennsylvanica, showing stipe between calyx and corolla.]

[Illustration: Fig. 357. Flower of a