345. =Its Nature.= The ovary matures into the Fruit. In the strictest
sense the fruit is the seed-vessel, technically named the PERICARP. But
practically it may include other parts organically connected with the
pericarp. Especially the calyx, or a part of it, is often incorporated
with the ovary, so as to be undistinguishably a portion of the pericarp,
and it even forms along with the receptacle the whole bulk of such
edible fruits as apples and pears. The receptacle is an obvious part in
blackberries, and is the whole edible portion in the strawberry.
346. Also a cluster of distinct carpels may, in ripening, be
consolidated or compacted, so as practically to be taken for one fruit.
Such are raspberries, blackberries, the Magnolia fruit, etc. Moreover,
the ripened product of many flowers may be compacted or grown together
so as to form a single compound fruit.
347. =Its kinds= have therefore to be distinguished. Also various names
of common use in descriptive botany have to be mentioned and defined.
348. In respect to composition, accordingly, fruits may be classified
into
_Simple_, those which result from the ripening of a single pistil, and
consist only of the matured ovary, either by itself, as in a cherry, or
with calyx-tube completely incorporated with it, as in a gooseberry or
cranberry.
_Aggregate_, when a cluster of carpels of the same flower are crowded
into a mass; as in raspberries and blackberries.
[Illustration: Fig. 366. Forming fruit (capsule) of Gaultheria, with
calyx thickening around its base. 367. Section of same mature, the
berry-like calyx nearly enclosing the capsule.]
[Illustration: Fig. 368. Section of a part of a strawberry. Compare with
Fig. 360.]
[Illustration: Fig. 369. Similar section of part of a blackberry. 370.
One of its component simple fruits (drupe) in section, showing the pulp,
stone, and contained seed; more enlarged. Compare with Fig. 375.]
_Accessory_ or _Anthocarpous_, when the surroundings or supports of the
pistil make up a part of the mass; as does the loose calyx changed into
a fleshy and berry-like envelope of our Wintergreen (Gaultheria, Fig.
366, 367) and Buffalo-berry, which are otherwise simple fruits. In an
aggregate fruit such as the strawberry the great mass is receptacle
(Fig. 360, 368); and in the blackberry (Fig. 369) the juicy receptacle
forms the central part of the savory mass.
_Multiple_ or _Collective_, when formed from several flowers
consolidated into one mass, of which the common receptacle or axis of
inflorescence, the floral envelopes, and even the bracts, etc., make a
part. A mulberry (Fig. 408, which superficially much resembles a
blackberry) is of this multiple sort. A pine-apple is another example.
349. In respect to texture or consistence, fruits may be distinguished
into three kinds, viz.--
_Fleshy Fruits_, those which are more or less soft and juicy throughout;
_Stone Fruits_, or _Drupaceous_, the outer part fleshy like a berry,
the inner hard or stony, like a nut; and
_Dry Fruits_, those which have no flesh or pulp.
350. In reference to the way of disseminating the contained seed, fruits
are said to be
_Indehiscent_ when they do not open at maturity. Fleshy fruits and stone
fruits are of course indehiscent. The seed becomes free only through
decay or by being fed upon by animals. Those which escape digestion are
thus disseminated by the latter. Of dry fruits many are indehiscent; and
these are variously arranged to be transported by animals. Some burst
irregularly; many are
_Dehiscent_, that is, they split open regularly along certain lines, and
discharge the seeds. A dehiscent fruit almost always contains many or
several seeds, or at least more than one seed.
[Illustration: Fig. 371. Leafy shoot and berry (cut across) of the
larger Cranberry, Vaccinium macrocarpon.]
[Illustration: Fig. 372, 373. Pepo of Gourd, in section. 373. One carpel
of same in diagram.]
[Illustration: Fig. 374. Longitudinal and transverse sections of a pear
(pome).]
351. The principal kinds of fruit which have received substantive names
and are of common use in descriptive botany are the following. Of fleshy
fruits the leading kind is
352. =The Berry=, such as the gooseberry and currant, the blueberry and
cranberry (Fig. 371), the tomato, and the grape. Here the whole flesh is
soft throughout. The orange is a berry with a leathery rind.
353. =The Pepo=, or _Gourd-fruit_, is a hard-rinded berry, belonging to
the Gourd family, such as the pumpkin, squash, cucumber, and melon, Fig.
372, 373.
354. =The Pome= is a name applied to the apple, pear (Fig. 374), and
quince; fleshy fruits, like a berry, but the principal thickness is
calyx, only the papery pods arranged like a star in the core really
belonging to the carpels. The fruit of the Hawthorn is a drupaceous
pome, something between pome and drupe.
355. Of fruits which are externally fleshy and internally hard the
leading kind is
356. =The Drupe=, or _Stone-fruit_; of which the cherry, plum, and peach
(Fig. 375) are familiar examples. In this the outer part of the
thickness of the pericarp becomes fleshy, or softens like a berry, while
the inner hardens, like a nut. From the way in which the pistil is
constructed, it is evident that the fleshy part here answers to the
lower, and the stone to the upper face of the component leaf. The layers
or concentric portions of a drupe, or of any pericarp which is thus
separable, are named, when thus distinguishable into three portions,--
_Epicarp_, the external layer, often the mere skin of the fruit,
_Mesocarp_, the middle layer, which is commonly the fleshy part, and
_Endocarp_, the innermost layer, the stone. But more commonly only two
portions of a drupe are distinguished, and are named, the outer one
_Sarcocarp_ or _Exocarp_, for the flesh, the first name referring to the
fleshy character, the second to its being an external layer; and
_Putamen_ or _Endocarp_, the _Stone_, within.
[Illustration: Fig. 375. Longitudinal section of a peach, showing flesh,
stone, and seed.]
357. The typical or true drupe is of a single carpel. But, not to
multiply technical names, this name is extended to all such fruits when
fleshy without and stony within, although of compound pistil,--even to
those having several or separable stones, such as the fruit of Holly.
These stones in such drupes, or drupaceous fruits, are called _Pyrenae_,
or _Nucules_, or simply _Nutlets_ of the drupe.
358. Of Dry fruits, there is a greater diversity of kinds having
distinct names. The indehiscent sorts are commonly one-seeded.
[Illustration: Fig. 376. Akene of a Buttercup. 377. The same, divided
lengthwise, to show the contained seed.]
[Illustration: Fig. 378. Akene of Virgin's-bower, retaining the
feathered style, which aids in dissemination.]
359. =The Akene or Achenium= is a small, dry and indehiscent one-seeded
fruit, often so seed-like in appearance that it is popularly taken for a
naked seed. The fruit of the Buttercup or Crowfoot is a good example,
Fig. 376, 377. Its nature, as a ripened pistil (in this case a simple
carpel), is apparent by its bearing the remains of a style or stigma, or
a scar from which this has fallen. It may retain the style and use it in
various ways for dissemination (Fig. 378).
360. The fruit of Compositae (though not of a single carpel) is also an
akene. In this case the pericarp is invested by an adherent calyx-tube;
the limb of which, when it has any, is called the PAPPUS. This name was
first given to the down like that of the Thistle, but is applied to all
forms under which the limb of the calyx of the "compound flower"
appears. In Lettuce, Dandelion (Fig. 384), and the like, the achenium as
it matures tapers upwards into a slender beak, like a stalk to the
pappus.
[Illustration: Fig. 379. Akene of Mayweed (no pappus). 380. That of
Succory (its pappus a shallow cup). 381. Of Sunflower (pappus of two
deciduous scales). 382. Of Sneezeweed (Helenium), with its pappus of
five scales. 383. Of Sow-Thistle, with its pappus of delicate downy
hairs. 384. Of the Dandelion, its pappus raised on a long beak.]
361. =A Cremocarp= (Fig. 385), a name given to the fruit of Umbelliferae,
consists as it were of a pair of akenes united completely in the
blossom, but splitting apart when ripe into the two closed carpels. Each
of these is a _Mericarp_ or _Hemicarp_, names seldom used.
362. =A Utricle= is the same as an akene, but with a thin and bladdery
loose pericarp; like that of the Goosefoot or Pigweed (Fig. 386). When
ripe it may burst open irregularly to discharge the seed; or it may open
by a circular line all round, the upper part falling off like a lid; as
in the Amaranth (Fig. 387).
[Illustration: Fig. 385. Fruit (cremocarp) of Osmorrhiza; the two
akene-like ripe carpels separating at maturity from a slender axis or
carpophore.]
[Illustration: Fig. 386. Utricle of the common Pigweed (Chenopodium
album).]
[Illustration: Fig. 387. Utricle (pyxis) of Amaranth, opening all round
(circumscissile).]
363. =A Caryopsis, or Grain=, is like an akene with the seed adhering to
the thin pericarp throughout, so that fruit and seed are incorporated
into one body; as in wheat, Indian corn, and other kinds of grain.
364. =A Nut= is a dry and indehiscent fruit, commonly one-celled and
one-seeded, with a hard, crustaceous, or bony wall, such as the
cocoa-nut, hazelnut, chestnut, and the acorn (Fig. 37, 388.) Here the
involucre, in the form of a cup at the base, is called the CUPULE. In
the Chestnut the cupule forms the bur; in the Hazel, a leafy husk.
[Illustration: Fig. 388. Nut (acorn) of the Oak, with its cup or
cupule.]
365. =A Samara, or Key-fruit=, is either a nut or an akene, or any other
indehiscent fruit, furnished with a wing, like that of Ash (Fig. 389),
and Elm (Fig. 390). The Maple-fruit is a pair of keys (Fig. 391).
366. Dehiscent Fruits, or Pods, are of two classes, viz., those of a
simple pistil or carpel, and those of a compound pistil. Two common
sorts of the first are named as follows:--
367. =The Follicle= is a fruit of a simple carpel, which dehisces down
one side only, i. e. by the inner or ventral suture. The fruits of Marsh
Marigold (Fig. 392), Paeony, Larkspur, and Milkweed are of this kind.
[Illustration: Fig. 389. Samara or key of the White Ash, winged at end.
390. Samara of the American Elm, winged all round.]
[Illustration: Fig. 391. Pair of samaras of Sugar Maple.]
[Illustration: Fig. 392. Follicle of Marsh Marigold (Caltha palustris).]
[Illustration: Fig. 393. Legume of a Sweet Pea, opened.]
[Illustration: Fig. 394. Loment or jointed legume of a Tick-Trefoil
(Desmodium).]
368. =The Legume= or true Pod, such as the peapod (Fig. 393), and the
fruit of the Leguminous or Pulse family generally, is one which opens
along the dorsal as well as the ventral suture. The two pieces into
which it splits are called VALVES. A LOMENT is a legume which is
constricted between the seeds, and at length breaks up crosswise into
distinct joints, as in Fig. 394.
369. The pods or dehiscent fruits belonging to a compound ovary have
several technical names: but they all may be regarded as kinds of
370. =The Capsule=, the dry and dehiscent fruit of any compound pistil.
The capsule may discharge its seeds through chinks or pores, as in the
Poppy, or burst irregularly in some part, as in Lobelia and the
Snapdragon; but commonly it splits open (or is _dehiscent_) lengthwise
into regular pieces, called VALVES.
[Illustration: Fig. 395. Capsule of Iris, with loculicidal dehiscence;
below, cut across.]
[Illustration: Fig. 396. Pod of a Marsh St. John's-wort, with septicidal
dehiscence.]
371. Regular _Dehiscence_ in a capsule takes place in two ways, which
are best illustrated in pods of two or three cells. It is either
_Loculicidal_, or, splitting directly into the _loculi_ or cells, that
is, down the back (or the dorsal suture) of each cell or carpel, as in
Iris (Fig. 395); or
_Septicidal_, that is, splitting through the partitions or _septa_, as
in St. John's-wort (Fig. 396), Rhododendron, etc. This divides the
capsule into its component carpels, which then open by their ventral
suture.
[Illustration: Fig. 397, 398. Diagrams of the two modes.]
[Illustration: Fig. 399. Diagram of septifragal dehiscence of the
loculicidal type. 400. Same of the septicidal or _marginicidal_ type.]
372. In loculicidal dehiscence the valves naturally bear the partitions
on their middle; in the septicidal, half the thickness of a partition is
borne on the margin of each valve. See the annexed diagrams. A variation
of either mode occurs when the valves break away from the partitions,
these remaining attached in the axis of the fruit. This is called
_Septifragal_ dehiscence. One form is seen in the Morning-Glory (Fig.
400).
373. The capsules of Rue, Spurge, and some others, are both loculicidal
and septicidal, and so split into half-carpellary valves or pieces.
374. =The Silique= (Fig. 401) is the technical name of the peculiar pod
of the Mustard family; which is two-celled by a false partition
stretched across between two parietal placentae. It generally opens by
two valves from below upward, and the placentae with the partition are
left behind when the valves fall off.
375. =A Silicle or Pouch= is only a short and broad silique, like that
of the Shepherd's Purse, Fig. 402, 403.
[Illustration: Fig. 401. Silique of a Cadamine or Spring Cress.]
[Illustration: Fig. 402. Silicle of Shepherd's Purse.]
[Illustration: Fig. 403. Same, with one valve removed.]
[Illustration: Fig. 404. Pyxis of Purslane, the lid detaching.]
376. =The Pyxis= is a pod which opens by a circular horizontal line, the
upper part forming a lid, as in Purslane (Fig. 404), the Plantain,
Henbane, etc. In these the dehiscence extends all round, or is
_circumscissile_. So it does in Amaranth (Fig. 387), forming a
one-seeded utricular pyxis. In Jeffersonia, the line does not separate
quite round, but leaves a portion for a hinge to the lid.
377. Of Multiple or Collective Fruits, which are properly masses of
fruits aggregated into one body (as is seen in the Mulberry (Fig. 408),
Pine-apple, etc.), there are two kinds with special names and of
peculiar structure.
[Illustration: Fig. 405. A fig-fruit when young. 406. Same in section.
407. Magnified portion, a slice, showing some of the flowers.]
[Illustration: Fig. 408. A mulberry. 409. One of the grains younger,
enlarged; seen to be a pistillate flower with calyx becoming fleshy.
410. Same, with fleshy calyx cut across.]
378. =The Syconium or Fig-fruit= (Fig. 405, 406) is a fleshy axis or
summit of stem, hollowed out, and lined within by a multitude of minute
flowers, the whole becoming pulpy, and in the common fig, luscious.
379. =The Strobile or Cone= (Fig. 411), is the peculiar multiple fruit
of Pines, Cypresses, and the like; hence named _Coniferae_, viz.
cone-bearing plants. As already shown (313), these cones are _open
pistils_, mostly in the form of flat scales, regularly overlying each
other, and pressed together in a spike or head. Each scale bears one or
two naked seeds on its inner face. When ripe and dry, the scales turn
back or diverge, and in the Pine the seed peels off and falls, generally
carrying with it a wing, a part of the lining of the scale, which
facilitates the dispersion of the seeds by the wind (Fig. 412, 413). In
Arbor-Vitae, the scales of the small cone are few, and not very unlike
the leaves. In Cypress they are very thick at the top and narrow at the
base, so as to make a peculiar sort of closed cone. In Juniper and Red
Cedar, the few scales of the very small cone become fleshy, and ripen
into a fruit which closely resembles a berry.
[Illustration: Fig. 411. Cone of a common Pitch Pine. 412. Inside view
of a separated scale or open carpel; one seed in place: 413, the other
seed.]