The flowers are most frequently regular, 5-merous in the three
most external whorls, eucyclic and perigynous or epigynous, less
frequently hypogynous. A characteristic feature is that the ovary is
_tricarpellary_, _unilocular_, and with 3 _parietal_ placentæ which
sometimes meet in the central line (_Cucurbitaceæ_). The styles are
generally free and _bifid_. To all these characteristics, however,
there are exceptions. ~The Cucurbitaceæ are sometimes placed among the
Sympetalæ, close to the Campanulinæ, but they are not allied to the
Sympetalæ, from which they differ especially, for instance, in the
structure of the ovule. The position of the Begoniaceæ in this family
is also open to doubt.~
[Illustration: FIG. 515.--_Passiflora cœrulea_ (reduced).]
Order 1. =Passifloraceæ= (=Passion-flowers=). The majority are
herbs which climb by means of tendrils (modified branches) and have
scattered, stipulate leaves, often palminerved and lobed (Fig. 515).
The flowers, which are often large and beautiful, are regular, ☿, with
S5, P5, A5, G3; the calyx and corolla are _perigynous_, and immediately
inside the corolla is the “corona,” consisting of numerous, tapering,
filamentous bodies, or sometimes united in rings, most frequently
petaloid and coloured; the stamens are raised on a long, round
internode above the _cup-like receptacle_; immediately above these is
the gynœceum with its 3 free styles and capitate stigmas; the ovary is
unilocular with 3 parietal placentæ. Fruit most frequently a _berry_.
The seeds have an aril.
210 species; especially in Tropical America. Several
_Passiflora_-species are ornamental plants, and the fruits of
some species are edible.
Order 2. =Papayaceæ.= The best known representative is the Papaw
(_Carica papaya_), a Tropical American tree whose stem is usually
unbranched, and bears at its summit several large, palmilobed leaves
on long stalks. The stem and leaves have latex. The large, Melon-like
berries are edible, and for this reason it is cultivated in the
Tropics. Flowers unisexual, with slightly different structure in
the ♂-and ♀-flowers, besides intermediate forms. The ♂-flower has a
gamopetalous, the ♀-flower a polypetalous corolla.--The milky juice
contains a substance with similar action to pepsine. 10 stamens. 5
carpels.
Order 3. =Turneraceæ.= 85 species; especially in America.
Order 4. =Samydaceæ.= 160 species; tropical.
Order 5. =Loasaceæ.= Herbaceous plants seldom shrubs, sometimes
climbing, and nearly always studded with _stiff hairs_, in some
instances stinging or hooked. The leaves are most frequently palmilobed
and without stipules. The flowers are regular, ☿, polypetalous,
entirely _epigynous_, with 4–5 sepals, petals and stamens, or more
frequently (by splitting) many stamens, those which are placed before
the sepals being generally barren and more or less petaloid; carpels
most frequently 3, united into an inferior, unilocular ovary with 3
parietal placentæ, above which the receptacle is generally more or less
prolonged. Fruit a capsule; in _Gronovia_ an ovary with 1 ovule and
fruit a nut.
115 species; principally from S. Am. A number of annuals are
often grown in our gardens: _Bartonia aurea_ (California);
_Mentzelia_; _Cajophora_; _Gronovia_.
Order 6. =Datiscaceæ.= 4 species, especially in the Tropics.--_Datisca
cannabina_ (Asia Minor) resembles the Hemp in external appearance. The
flowers are diœcious, insignificant; ♂-flowers: a low, gamosepalous
calyx, no corolla, and an indefinite number of stamens; ♀-flowers;
_epigynous_; ovary unilocular with free, mostly bifid, styles, and
generally 3 parietal placentæ. In most cases the ovary is not entirely
closed at the top (as in _Reseda_).
[Illustration: FIG. 516.--_Begonia rex_ (reduced).]
Order 7. =Begoniaceæ.= This order principally comprises herbs or
under-shrubs with succulent stems (having scattered vascular bundles
in the pith); the leaves are arranged in two rows (a divergence of
1/2) and _are asymmetrical_, as a rule more or less obliquely cordate,
or ovate with cordate base (Fig. 516); large, caducous stipules are
present. Inflorescences dichasial, or unipared scorpioid cymes; the
flowers are unisexual; the first ones (the oldest) are ♂-flowers, while
♀-flowers are found especially on the younger axes. The ♂-flowers
have most frequently 2 + 2 coloured perianth-leaves, and many stamens
collected into a head in the centre of the flower; the ♀-flowers are
_epigynous_ with 5 coloured perianth-leaves (placed spirally with a
divergence of 2/5) and a trilocular ovary, bearing 3 bifid styles and
3 wings (the wings usually of unequal size); in the inner angle of
each loculus there is one large projecting placenta, or two plate-like
placentæ (the bent back edges of the carpels) studded with ovules.
Fruit a capsule, with many extremely small seeds.--_Begonia._
420 species; almost all from the Tropics (Am., Asia).--Many
species, with varieties and hybrids, are ornamental plants in
houses and conservatories, chiefly on account of the form,
colour and markings of their leaves; but also for their very
beautiful flowers. They reproduce easily by adventitious buds
from leaves and portions of leaves placed on damp soil; some
have bulbils. Like the Oxalideæ they contain an acid sap.
[Illustration: FIG. 517.--_Ecballium agreste._ Diagram of a ♂-and
a ♀-flower.]
Order 8. =Cucurbitaceæ.= The flower is _epigynous_, and, as a rule,
is also provided with a leaf-like, cup- or bell-shaped receptacle
above the ovary, to which the perianth and stamens are attached; the
flowers are regular, _unisexual_, with rudiments of the other sex,
and 5-merous: sepals 5, narrow and pointed, with the median sepal
posterior (Fig. 517), petals 5, stamens 5, and carpels 3 (rarely 4–5);
the corolla is _gamopetalous_ in the majority, polypetalous in some;
generally plicate-valvate in the bud. _The anthers in the ♂-flowers are
extrorse, and monothecious, i.e. only one half of each of the anthers
of the 5 stamens is developed_, the _pollen-sac_ having frequently a
peculiar [tilde]-shaped curve (Fig. 518 _A_, _B_); the stamens are
_either all united_ into a column (_e.g._ in _Cucurbita_), or they
are _united in pairs_, so that only one remains free (Figs. 517 _A_;
518 _A_); in the latter case there appears to be one small stamen
with a [tilde]-shaped, curved pollen-sac and two larger ones, each
with two curved pollen-sacs placed as in Fig. 517 _A_. The original
form appears to be _Fevillea_ with free petals and 5 free stamens.
Sometimes the rudiment of a gynœceum is present. The carpels are united
into an _ovary_ with 3 (4–5) placentæ formed by their united edges.
These are thick, fleshy, and _bifid_, bearing a number of ovules on
each side (Figs. 517 _B_; 518 _C_, _D_); in general the placentæ are
so large that they not only meet in the centre, but also fill up the
ovary as far as the wall of the pericarp. The whole interior of the
fruit thus becomes a juicy mass in which three lines may be seen,
meeting in the centre (the boundaries of the individual placentæ),
and near the circumference 6 groups of seeds (Fig. 518 _D_). When the
carpels are equal in number to the petals they alternate with them.
The _style_ is short and thick, and generally divided into 3 (4–5)
branches, with a horse-shoe shaped stigma on each branch (Fig. 518
_C_). The _fruit_ is most frequently a many-seeded _berry_; in some it
attains a considerable size and has a firm external layer (_Cucurbita_,
_Lagenaria_, etc.). _The embryo is straight_, has _no endosperm_,
but contains a large quantity of _oil_. The exceptions to the above
characters will be found under the genera.
[Illustration: FIG. 518.--_Citrullus colocynthis_: _A_ ♂-flower,
cut open and spread out; _B_ stamen; _C_ ♀-flower in long
section; _h_ receptacle; _ca_ calyx; _D_ transverse section of
ovary.]
Exclusively herbs, generally with stiff hairs and yellow flowers. Many
species are annuals, others are perennial, having tuberous roots or
hypocotyls. The leaves are scattered, long-stalked, in most cases more
or less heart-shaped, palminerved, palmilobed, and exstipulate; in
their axils are found both flowers (singly, or in an inflorescence)
and a vegetative bud, and outside the axil, _on the anodic[37] side of
the leaf, a simple or branched tendril_, by which the plant _climbs_
(exceptions: _e.g._ _Ecballium_).
The position of the flowers, branches and tendrils situated
in and near the leaf-axils is as follows. In the leaf-axils,
a flower is borne (as a branch of the first order), ♂ or ♀,
according to the conditions of the various genera. This branch
is not situated in the centre of the axil, but is removed
slightly towards the anodic side of the leaf. Of its two
bracteoles as a rule only the one lying on the anodic side is
developed, namely as a tendril, which is displaced to a position
outside the axil. The branch of the first order bears on its
catodic side an inflorescence (in the axil of the suppressed
bracteole), on the anodic side a vegetative bud which grows out
into a branch like the main axis. The subtending leaf of this
branch is thus the tendril; but when it has several arms the
condition is complicated by the appearance of an accessory bud
which unites with its subtending leaf, the tendril, its leaves
also becoming tendrils (situated on an undeveloped internode);
the many-branched tendril is thus a branch, and the tendril-arms
are its leaves, except the main arm which is its subtending
leaf. Other explanations of these difficult relations have
been given.--The _germination_ is somewhat peculiar, owing to
the fact that a heel-like prolongation is formed at the base
of the hypocotyl to assist in separating the two halves of the
testa from each other, and to facilitate the unfolding of the
cotyledons.
_Cucurbita_ (Pumpkin, Marrow) has branched tendrils; the flowers are
monœcious, and are borne singly; the corolla is bell-shaped, and
divided almost as far as the middle. The stamens are all united into
a tube; the compressed seeds have a thick, blunt edge.--_Cucumis_ has
(generally) unbranched tendrils; the ♀-flowers are borne singly, whilst
the ♂-flowers are borne in groups: the corolla is divided nearly as
far as the base, and the stamens are united 2-2-1. The connective is
elongated above the anthers. The seeds have a sharp edge.--_Citrullus_
(Fig. 518) has a corolla similar to _Cucumis_, but ☿-and ♂-flowers are
borne singly; the stigma is only 3-lobed, the fruit most frequently
spherical.--_Ecballium_ (Squirting Cucumber, only 1 species, E.
_elaterium_) has no tendrils, and is therefore not a climber. The
oblong fruit is pendulous from the apex of its stalk, and when ripe is
distended with an acrid, watery fluid; on being touched the fruit is
detached, and the seeds, together with the watery fluid, are violently
ejected through the aperture formed at the base of the fruit. The
♂-flowers are borne in racemes near the solitary ♀-flowers (Fig.
517).--_Bryonia_ (White Bryony) has chiefly unbranched tendrils and
small, greenish-yellow, usually diœcious flowers with rotate corolla,
in many-flowered inflorescences; the small, spherical berry has no
specially firm outer layer, and generally only few seeds. The tap-root
and a few of the other roots are tuberous. _B. alba_ (berry black;
monœcious) and _dioica_ (berry red; diœcious). ~Among other genera may
be mentioned: _Lagenaria_ (Gourd); the fruit has a woody external
layer which, after the removal of the pulpy integument, may be used
as a gourd. _Luffa_ has a polypetalous corolla; the fruit is dry, and
consists internally of a network of vascular bundles; it opens by an
aperture at the summit. _Benincasa_; the fruit has a close, bluish
coating of wax. _Trichosanthes_ (Snake Cucumber) has a thin, round,
long and curved fruit. _Momordica_; the fleshy fruit opens and ejects
the seeds. _Cyclanthera_ takes its name from the staminal column which
is found in the centre of the ♂-flower, bearing a bilocular, ring-like
anther which opens by a horizontal cleft. The fruit is unilocular by
suppression, has 1 placenta, and when touched opens and ejects the
seeds. _Sicyos_ and _Sechium_ have only unilocular ovaries with one
pendulous ovule. _Sechium_ has, moreover, 5 free stamens, of which only
one is halved, the other 4 having both halves of the anther. _Fevillea_
and _Thladiantha_ also have 5 free stamens. _Dimorphochlamys_ has
dimorphic flowers.~
POLLINATION is effected by insects, chiefly bees or wasps,
the nectar being secreted by the inner, yellow portion of the
receptacle; in the ♂-flower access is gained to the nectar
through the slits between the stamens, which arch over the
nectary.--85 genera; about 637 species; especially in the
Tropics. Only two are found in the whole of N. Europe, _Bryonia
alba_ and _dioica_; in S. Europe, _Ecballium_ also. Most of
the cultivated species have been obtained from Asia, such as
the Cucumber, Melon, Colocynth, several _Luffa_-species (the
“Gourds” mentioned in Scripture are _Cucumis chate_); from
Africa, the Water-melon, _Cucurbita maxima_, and others; from
S. Am., no doubt, the Pumpkin (_C. pepo_ and _melopepo_). USES.
Many species are used in medicine or for domestic purposes.
_Bitter_, _poisonous properties_ are found; the fruits of the
two _officinal_ ones are purgative: _Citrullus colocynthis_
(Mediterranean, E. India, Ceylon) and _Ecballium elaterium_,
as well as various tropical species, the roots of Bryonia,
etc.--The following are cultivated AS ARTICLES OF FOOD: Pumpkin
(_Cucurbita pepo_, etc.), Cucumber (_Cucumis sativus_), Melon
(_Cucumis melo_), the Water-melon (_Citrullus vulgaris_),
_Sechium edule_ (Chocho), certain species of _Luffa_ (the
young fruit). The Bottle Gourd is cultivated in tropical
countries for the sake of its hard pericarp, which is useful
for bowls, bottles, etc. The fruits of _Luffa_ have a number
of reticulately felted, tolerably firm vascular bundles, which
render them serviceable in various ways (as a kind of “sponge”).
The Cucurbits are of no use in the manufactures. Only a few are
cultivated as ornamental plants, chiefly as curiosities.