Chapter II: ACROGYNÆ. The apex of the stem or of certain branches is adapted (9)

Of the other genera some have a bell-shaped, gamosepalous
calyx, some have no corolla, the anthers of some open at the
apex (_Aristotelia_, _Elæocarpus_, etc.), the majority have
a capsule, some have berries, or drupes, some separate into
fruitlets, etc.--_Corchorus_, _Triumfetta_ (nut, with hooked
bristles), _Luehea_, _Apeiba_, etc. _Sparmannia_ is an African
genus; 4-merous flowers; fruit a warted capsule; filaments
numerous and sensitive to touch, the external ones are without
anthers and moniliform above. The plant is covered with numerous
soft and stellate hairs, and at the apex of the branches bears
several cymose umbels.

POLLINATION in _Tilia_ is effected by insects, especially
bees and Diptera, which swarm round the tree tops, allured
by the numerous strongly-scented flowers and the easily
accessible honey (formed in the hollow sepals). As the flowers
are pendulous, the nectar is protected from ruin; and, in
addition, the inflorescence is more or less concealed beneath
the foliage-leaf. Self-pollination is impossible, on account of
protandry.--About 470 species (nearly all trees and shrubs);
especially in the Tropics, only a few being found in the
temperate, none in the polar regions, or in high mountainous
districts.--The inflorescence of the native species of _Tilia_
is medicinal. The wood is used for charcoal.--The majority are
used for timber, and for the sake of the bast (“Bast,” “Jute,”
the bast of _Corchorus textilis_, _Luehea_, and others).

Order 3. =Malvaceæ= (=Mallows=). The plants are easily recognised by the scattered, simple, _palminerved_, most frequently lobed, stipulate _leaves_, folded in the bud; the perfect, regular, hypogynous flowers, with _gamosepalous_, persistent, 5-merous calyx with _valvate_ æstivation; the 5 _petals twisted_ in the bud and united with one another at the base, and by the 5 _apparently numerous stamens_ (Figs. 445, 448), with the filaments _united into a tube_, with _reniform bilocular anthers_ opening by a crescentic slit (in 2 valves). Carpels 3–∞ united into one gynœceum; the _embryo is curved and the cotyledons are folded_ (Figs. 447, 451); endosperm scanty, often mucilaginous.--Most of the plants belonging to this order are herbs, often closely studded with _stellate hairs_. The leaves are most frequently palmatifid or palmatisect.

An _epicalyx_ is often found formed by _floral-leaves_ placed
close beneath the calyx, in some 3, in others several. The
median sepal is posterior in the species without epicalyx,
often anterior in those which have an epicalyx.--The petals are
_twisted either to the right or to the left_ in accordance with
the spiral of the calyx; they are most frequently oblique, as
in the other plants with twisted corollas, so that the portion
covered in the æstivation is the most developed. The corolla
drops off as a whole, united with the staminal tube.--Only
the 5 petal-stamens are developed, but they are divided into
a number of stamens, placed in 2 rows, and provided only with
_half_-anthers (leaf-segments, see Fig. 446; the sepal-stamens
are completely suppressed); these 5 staminal leaves are then
united into a tube, frequently 5-dentate at the top, and
bearing the anthers on its external side. The pollen-grains
are specially large, spherical and spiny. There are from 3 to
about 50 carpels united into one gynœceum and placed round the
summit of the axis which most frequently projects between them.
There is only 1 style, which is generally divided into as many
stigma-bearing branches as there are carpels (Figs. 445, 448).
The fruit is a schizocarp or capsule. Endosperm (Figs. 447 A,
451) scanty, often mucilaginous round the _embryo_, which is
rich in oil.

The order is the most advanced type of Columniferæ; it stands
especially near to the Sterculiaceæ, but is separated from these
and from the Tiliaceæ, among other characters, by its 2-locular
(ultimately 1-chambered) anthers.

The sub-orders may be arranged as follows:--

I. Carpels in one whorl.

=A.= =The fruit a capsule=, ~most frequently with loculicidal dehiscence, and many seeds in each loculus~.

=1.= GOSSYPIEÆ. The staminal-column is naked at the apex, blunted, or 5-dentate.--_Gossypium_ (the Cotton plant) has an epicalyx of 3 large ovate-cordate leaves, an almost entire, low and compressed calyx. Solitary flowers. Large, most frequently yellow, corollas. A 3–5-valved capsule with many spherical seeds. “Cotton” is the seed-hairs developed upon the entire surface of the seeds (Fig. 447), and consists of long, 1-cellular hairs, filled with air (and therefore white); these are thin-walled, with a large lumen, and during drying twist spirally, and come together more or less in the form of bands. They consist of cellulose, and have a cuticle.--_Hibiscus_ has several, most frequently narrow, epicalyx-leaves, a distinct 5-toothed or 5-partite calyx.--_Abutilon_; _Modiola_.

=2.= BOMBACEÆ. The staminal tube is more or less deeply cleft
into bundles, sometimes almost to the base; pollen smooth,
style simple with capitate, lobed stigma. Almost all plants
belonging to this group are trees, and in many instances have
large barrel-shaped stems, that is, swollen in the centre, and
sometimes covered with large warts. The wood is exceptionally
light and soft. The flowers are often enormously large, and have
beautiful petals; in some they unfold before the leaves. The
capsule-wall is sometimes closely covered on its inner service
with long, silky, woolly hairs, while the seeds themselves
are generally without hairs. These hairs, however, on account
of their brittle nature, cannot be used like those of the
Cotton-plant. Digitate leaves are found in the _Baobab-tree_
(_Adansonia_) from Africa, noted for its enormously thick, but
short stem, and in the American _Silk-cotton trees_ (_Bombax_,
_Eriodendron_, _Chorisia_). _Ochroma_, _Cheirostemon_, _Durio_,
and others also belong to this group. _Durio_ is noted for its
delicious fruits, which have a most unpleasant smell.

[_Bombax malabaricum_ is diplostemonous; the five sepal-stamens
repeatedly branch, and the filaments bear unilocular anthers;
the five petal-stamens bear bilocular anthers.]

=B.= =Schizocarps=, with 1-seeded fruitlets, most frequently nut-like and reniform (Figs. 449, 451).

=3.= MALVEÆ, MALLOW GROUP. The carpels are arranged in one whorl (Fig. 449); the number of stylar-branches equals that of the carpels; fruitlets 1-seeded, reniform, indehiscent, but detaching themselves from one another and from the persistent central column (Figs. 450, 451).--~_Malva_ has an _epicalyx of 3 free leaves_. ~A flower with 2 suppressed bracteoles is situated in the axil of the foliage-leaves; one of these supports a homodromous foliage-shoot which forms a repetition of the main axis, the other an antidromous flower which continues the branching as a unipared scorpioid cyme.~--_Althæa_, Rose Mallow, has an _epicalyx of 6–9 leaves united at the base_.--~_Lavatera_, _Sida_, _Anoda_, _Bastardia_, etc., have no epicalyx.~

=4.= URENEÆ, have always only 5 carpels arranged in 1 whorl,
with 1 ovule in each loculus, and the fruit a schizocarp,
generally with nut-like fruitlets provided with warts and
hooks; but in some they dehisce by 2 valves (capsule). They
differ principally from the other groups _in having twice as
many stylar-branches as carpels_; the staminal tube is naked at
the point, blunt or 5 toothed.--The genera _Urena_, _Pavonia_,
_Malachra_, _Malvaviscus_ (with _berry-like fruits_) belong to
this group.

II. Carpels arranged in a spherical head in five groups opposite to the petals.

=5.= MALOPEÆ, differ from all the others in having a large
number of fruitlets arranged irregularly in a round head, and
separating considerably from each other even before maturity;
there is, however, only 1 style, divided into a corresponding
number of branches (this condition may be considered to have
arisen from the branching [dédoublement] of 5 _carpels_).
_Malope_ has 3 large, heart-shaped (_Kitaibelia_ 6–9)
epicalyx-leaves, united at the base. _Palava_ has no epicalyx.

POLLINATION. The majority have protandrous flowers, and are
pollinated by insects. Between the basal portions of the 5
petals, there are 5 nectaries, protected from the rain by
hairs, _e.g._ in _Malva silvestris_. When the flower first
opens the numerous anthers occupy the centre of the flower, and
the still undeveloped stigmas are concealed in the staminal
tube; in the next stage the anthers are withered and empty,
and the stigmas protrude and assume their places (Fig. 452).
The large-flowered forms, it appears, are pollinated only by
insects; but self-pollination takes place in small-flowered
forms, as, for example, in _Malva rotundifolia_, in which the
stylar-branches, twisting themselves, place the stigmas in
between the undeveloped anthers.

DISTRIBUTION. 800 species (63 genera), most of which are
natives of the Tropics, especially America. _Althæa_ and some
of the species of _Malva_ are natives of the temperate regions
of the Old World, the latter is also found in North America.
_Gossypium_ is tropical, no doubt especially Asiatic (_G.
herbaceum_ from India; _G. arboreum_ from Upper Egypt). Cotton
was introduced into Greece in the time of Herodotus, and was
cultivated in America before the arrival of the Europeans.

USES. Pungent and poisonous properties are entirely wanting;
_mucilage_, on the other hand, is found in abundance in all
parts of the plant. Medicinal: the root of _Althæa officinalis_,
leaves and flowers of _Malva_-species (_M. silvestris vulgaris_
and _borealis_) and _Gossypium_.--The seeds contain a large
quantity of _fatty oil_, which is in some cases extracted
(Cotton-seeds and others). _The seed-hairs of the Cotton
plant_ are the most important product of the order. The
cultivated forms of Cotton belong to several species: _G.
barbadense_, _herbaceum_, _religiosum_, _arboreum_ (Nankin),
_hirsutum_, and others. According to other botanists, there
are only 3 species. _Bast_ is obtained from _e.g. Hibiscus
cannabinus_ (Gambo-hemp, Africa), _Paritium tiliaceum_ and
_Sida retusa_. The fruits of certain species of _Hibiscus_
(_e.g. H. esculentus_, from Tropical Africa) are used in
tropical countries as a vegetable before they are ripe.--_The
colouring matter_ in the flowers of _Althæa rosea_, var.
_nigra_, is used for colouring wines, and hence is extensively
cultivated in certain parts of Europe.--_Ethereal oils and
sweet-scented flowers_ are rare; but several species possess
a peculiar musk-like odour (_Malva moschata_, _Hibiscus
abelmoschus_, and others).--Many are cultivated as _ornamental
plants_ on account of the large flowers, _e.g._ Hollyhock (_A.
rosea_, etc.), _Lavatera trimestris_, _Malope grandiflora_ and
_trifida_, _Malva_-species, _Hibiscus rosa sinensis_, _syriaca_;
_Sphæralcea_, etc.

Family 14. =Tricoccæ.=

The very large order _Euphorbiaceæ_ and three smaller ones belong to this family. They have in common: _unisexual_, hypogynous, frequently regular flowers, the perianth most frequently single, rarely double, or entirely wanting; there is such a great variety in the structure and parts of the flower that one only can be cited as the _rule_: viz. the simple gynœceum composed of 3 carpels forming a 3-locular ovary, which is frequently more or less deeply grooved (hence the name, _Tricoccæ_); in the inner angles of the loculi are found 1 or 2 (never several) pendulous (except _Empetraceæ_), anatropous ovules, with upward and outwardly turned, frequently swollen, micropyle (Fig. 455). The seed most frequently has a large endosperm and a straight embryo (Figs. 455 _B_, 464).--~The family approaches the nearest to the Gruinales and Columniferæ; it may perhaps be regarded as an offshoot from the Sterculiaceæ.~

Order 1. =Euphorbiaceæ.= Flowers unisexual. In each of the loculi of the ovary, generally 3, there are 1 or 2 pendulous ovules with upward and outwardly turned micropyle. The placenta protrudes above the ovules (Figs. 454, 461 _B_). On the ripening of the capsule the 3 carpels separate septicidally, frequently with great violence, ejecting the seeds and leaving a central column. Endosperm copious.--For the rest, the flowers present all stages, from genera with calyx and corolla, to those which are the most reduced in Nature, namely the naked, 1-stamened flowers of _Euphorbia_.

The same variety which is found in the flower is also present in the vegetative parts. Some are herbs, as our Spurges, others are shrubs and trees; some African _Euphorbia_-species even resemble the habit of a Cactus. Leaf-like branches with rudimentary leaves are found in _Phyllanthus_ (sub-genus _Xylophylla_) (Fig. 456). The leaves are scattered or opposite, often stipulate; they are nearly always simple. Large, highly-branched cells containing a great quantity of pungent latex are found in many, and watery juice in others. Glands and glandular hairs are general.--Only a few genera can be considered in this book.

As an example of the most perfect flowers (which partly reproduce the Geraniaceous type) may be mentioned, _Croton_, _Manihot_, and _Jatropha_; 5 sepals, 5 petals, sometimes gamopetalous, andrœcium diplostemonous, or many-stamened, often monodelphous.

FIG. 453.--♂-flower (magnified).

FIG. 454.--♀-flower in longitudinal section.

FIG. 455.--_A_ seed entire; _B_ in longitudinal section.]

_Ricinus_ (Castor-oil) (Figs. 453–455); monœcious; the ♂-flowers, situated in the lower portion of the inflorescence, have 5 perianth-leaves and a large number of branched stamens; the ♀-flower has 3–5 perianth-leaves; 3 bifid styles. Leaves peltate, palmately lobed. The seeds (Fig. 455) contain an abundance of fatty oil and large aleurone grains.--_Mercurialis_ (Mercury): the perianth is most frequently 3-merous; in the ♂-flowers 9–12 stamens; in the ♀-flowers most frequently a _2-locular_ gynœceum.--_Phyllanthus_: Pr3 + 3, A3, united in some and forming a column in the centre of the flower (Figs. 457, 458); _Xylophylla_ is a section of this genus.-- _Hura crepitans_ (Sand-box tree) has a many-carpellate gynœceum, which separates with great violence when ripe.--A drupe is found in _Hippomane mancinella_ (the Mancinil-tree, W. Ind.)--_Alchornea (Coelebogyne) ilicifolia_ is well known on account of its “parthenogenesis”; only the ♀-plant has been introduced into Europe, but it nevertheless produces seeds capable of germination; these have generally several embryos.

FIG. 456.--Leaf-like branch with flowers (nat. size).

FIG. 457.--♂-flower; and FIG. 458, ♀-flower (mag.).]

_Euphorbia_ (Spurge) has the most reduced flowers, which are borne in a very complicated inflorescence. Each ♂-flower (Fig. 460 _B_) is naked, and consists of one stamen only (terminal on the axis). In the closely allied genus _Anthostema_, a small perianth is situated at the place where, in _Euphorbia_, there is a joint in the “filament,” (Fig. 461 _A_). The ♀-flowers (Fig. 460) are naked, with a 3-locular ovary and 3 bifid styles. (_Anthostema_ has a distinct perianth (Fig. 461 _B_); in a few Euphorbias traces of a perianth are present). In _Euphorbia_ the ♂-and ♀-flowers are grouped into flower-like inflorescences termed “cyathia.” Each cyathium consists of a centrally placed ♀-flower which is first developed, surrounded by 5 groups of ♂-flowers (stamens) placed in a zig-zag, with a centrifugal order of development (Figs. 459, 460 _B_), that is, in unipared scorpioid cymes; these flowers are surrounded by an _involucre_ of 5 leaves united into a _bell-shaped structure_ (Fig. 459, 1–5) (resembling a calyx); on its edge are placed 4, generally crescent-like, yellow glands, one in each of the intervals, except one, between the lobes of the involucre (shaded in Fig. 459; see also Fig. 460 _A_). Scale-like thin structures (floral-leaves?) are situated between the ♂-flowers. The ♀-flower has a long stalk, and finally bends down on one side, namely to the place on the edge of the involucre where the gland is not developed. These cyathia are again arranged in an inflorescence which commences as a 3–5-rayed umbellate cyme (pleiochasium), the branches of which ramify dichasially and finally as scorpioid cymes.--Latex, with peculiar-shaped starch-grains, is found in laticiferous _cells_ (especially in the Cactus-like, leafless species.)

205 genera; more than 3,000 species; especially in the
Tropics.--Many are used on account of the oil, and of the
pungent (aperient, poisonous, anthelmintic, etc.) properties in
the latex or the seeds. OFFICINAL: “Cascarilla-bark” of _Croton
eluteria_; the fatty oil of the seeds of _Croton tiglium_
(Trop. Asia); “Castor oil” from _Ricinus communis_ (Africa,
and cultivated in all warm climates throughout the world);
the glandular hairs of _Mallotus philippinensis_ (“Kamala”);
this also yields a red dye. Gum “Euphorbium” is the hardened
(resinous) latex of the _Cactus_-like _Euphorbia resinifera_
(Morocco).--NUTRITIVE plants: _Manihot utilissima_ and other
species (Maniok, Am.). Their large, farinaceous roots form a
very important article of food in the Tropics (Cassava-flour,
Tapioca or Brazilian arrowroot). The fresh latex of the root in
some species is a powerful poison; but the poisonous properties
are diminished by roasting or cooking. _Caoutchouc_ is obtained
from _Siphonia elastica_ (Trop. S. Am.). The vegetable
tallow of the Chinese tallow-tree (_Stillingia sebifera_) is
used in large quantities in soap factories. An indigo-like
_dye_ is obtained from _Crozophora tinctoria_, and is also
found in _Mercurialis perennis_. Shellac is obtained from
_Aleurites laccifera_. ORNAMENTAL plants: _Acalypha_, _Croton_,
_Dalechampia_.--_Hippomane_ is poisonous.

Order 2. =Buxaceæ.= This order differs from the Euphorbiaceæ
in having the micropyle turned inwards; the ♂-flower has a
4-partite perianth and 4 stamens; the ♀-flower a 6-partite
perianth and 3 carpels. Capsule with loculicidal dehiscence,
the inner layer being detached elastically from the outer.--30
species. Shrubs without latex and with evergreen leaves.--_Buxus
sempervirens_ (Box) is an ornamental shrub (poisonous); it has a
very hard and valuable wood which is used for wood-engraving and
carving.

FIG. 462.--♂-flower with the 2 bracteoles and the solitary stamen.

FIG. 463.--♀-flower.

FIG. 464.--Longitudinal section of the ripe fruit.]

Order 3. =Callitrichaceæ.= Aquatic plants, growing at the bottom
of shallow water, with opposite, simple, undivided, entire,
exstipulate leaves, which are generally crowded and form a
rosette in the apex of the branches. The flowers are unisexual
(monœcious) and borne singly in the leaf-axils; they have no
perianth, but are provided with two delicate bracteoles; the
♂-flowers consist of only _1 terminal stamen_ (Fig. 462);
the ♀-flowers of a bicarpellate gynœceum (Fig. 463) which is
originally 2-locular, but later on becomes 4-locular, as in the
case of the gynœceum of the Labiatæ, by the formation of a false
partition-wall; in each loculus there is 1 pendulous ovule with
the micropyle turned outwards. Fruit a _4-partite schizocarp_
(Fig. 464). 25 species.--_Callitriche._

Order 4 (?). =Empetraceæ.= 4 species. _Empetrum_; _E. nigrum_
(Crowberry) is a heather-like, moorland, evergreen undershrub
with linear leaves, having a deep groove closed with hairs, on
the under side. The _erect ovules_ show the greatest deviation
from the Euphorbiaceæ. Diœcious (and ☿); S3, P3; in the
♂-flower, 3 stamens; in the ♀-flower, a 6–9-locular ovary. Fruit
a _drupe_.

Family 15. =Terebinthinæ.=

The diagram of the flower (Figs. 465–467) is the same as in the Gruinales, namely S, P, A2 and G in whorls of 5 (less frequently 3, 4, 6, 8), and the same modifications also occur with the suppression of the petal-stamens, etc. But a _ring_ or sometimes _cup-like glandular structure_ (_disc_) is found _between_ the andrœcium and the gynœceum (Figs. 465, 466). The flowers similarly are regular, _hypogynous_, ☿ and polypetalous, though exceptions are found to all these characters: thus, for example, united sepals and petals frequently occur, and, in some orders, unisexual flowers by the suppression of one sex. In most cases the flowers are small, greenish-yellow, and arranged in paniculate inflorescences. The carpels (most frequently 5) are free in a few, but generally united into a multilocular gynœceum; rarely more than 1 or 2 ovules in each loculus. The gynœceum in the Anacardiaceæ is so reduced that it has only 1 fertile loculus with 1 ovule.--The _ovules are epitropous_, _i.e._ anatropous with outward-turned raphe (except the Anacardiaceæ).--The majority of the species are trees and shrubs with scattered, often _compound (pinnate) leaves_ without stipules, and as in addition they frequently contain _aromatic, especially turpentine-like substances_, they assume a certain resemblance to the Walnut trees, and were formerly classed with them mainly on this account. In a series of genera the volatile, scented oils are found in special glands in the bark of the branches and in the leaves, in the latter case appearing as _pellucid dots_. This family includes several orders which are somewhat difficult to distinguish from each other.

Order 1. =Connaraceæ.= This order forms the connecting link
between Terebinthinæ and Rosifloræ (_Spiræa_) as well as
Leguminosæ, with which they are sometimes classed. The flowers
have 5 5-merous whorls; 2 ovules in each loculus; micropyle
turned upwards. Fruit a _follicle_, rarely a collection
of follicles. Seed with aril. Shrubs with scattered (most
frequently pinnate) leaves, without stipules. 170 species.
Tropical.

Order 2. =Meliaceæ.= Trees and shrubs with scattered, often
pinnate leaves without pellucid dots and exstipulate; the
leaflets are nearly always entire. Flowers small in paniculate
inflorescences. Calyx and corolla 4–5-merous; 2 whorls of
stamens; 3–5 carpels in the gynœceum. A very characteristic
feature is the union of the filaments into a tube, on the
edge of which stipule-like teeth are often found. There are
most frequently 2 ovules in the loculi; fruit a capsule with
many winged seeds in _Swietenia_ (Mahogany tree; Trop. Am.),
_Cedrela_, etc.; berries in others. The wood of _Cedrela_ is
used for making cigar boxes. 550 species; tropical.

Order 3. =Rutaceæ.= Leaves glandular with pellucid dots. The type is the same as that of the family. Flowers 4–5-merous. The ovary is most frequently 4–5-grooved. Disc well pronounced, often appearing as a “gynophore.” The majority are shrubs with alternate or opposite, compound, more rarely simple, leaves.

=A.= The ovary is deeply 2–5-cleft with basal styles which are more or less united; the carpels in some genera are entirely free (groups 1, 2). The fruit is capsular and most frequently dehisces like follicles along the ventral suture or septicidally, so that a horn-like internal layer (endocarp) separates elastically from the external layer.

=1.= ZANTHOXYLEÆ. _Zanthoxylum_; _Choisya_; _Evodia_.

=2.= BORONIEÆ. Australia.--_Correa._

=3.= DIOSMEÆ. Heather-like shrubs; Africa.--_Diosma_,
_Coleonema_, _Empleurum_ and _Barosma_. OFFICINAL: _Barosma
crenulata_ and _betulina_, “broad Buchu leaves” (_B.
serratifolia_ and _Empleurum serrulatum_, “narrow Buchu-leaves”).

=4.= RUTEÆ. _Ruta_ (Figs. 465–467) _graveolens_ is an herbaceous, glaucous, strongly smelling plant with bipinnate leaves and yellow flowers; the terminal flower is 5-merous, the others 4-merous (S. Eur.).--_Dictamnus_; zygomorphic flower. ~The individual carpels of the fruit separate from each other, and dehisce like follicles, upon which the internal layer is detached elastically and springs out, carrying the seeds with it. Several species are ornamental plants.~

=5.= CUSPARIEÆ. American. Flowers often zygomorphic with
gamopetalous corolla; stamens 5.--_Ticorea_; _Galipea_ (_G.
officinalis_; S. Am.; “Cortex angosturæ”); _Cusparia_;
_Almeidea_.

=B.= The ovary is entire or only slightly grooved; the style is terminal, undivided. The fruit is most frequently a drupe or berry.

=6.= TODDALIEÆ. _Ptelea_; winged fruit. The buds are enclosed in
the leaf-sheath. _Skimmia_; _Phellodendron_.

FIG. 468.--Branch with compound leaves.

FIG. 469.--Transverse section of fruit.

FIG. 470.--Flowers (after the removal of the petals).]

=7.= AURANTIEÆ, ORANGE GROUP. Fruit a berry with a leathery external layer.--The most typical flower is found for example in _Limonia_: S5, P5, A5 + 5, G5 (2–5).--_Citrus_ has 4–5–8-merous flowers, a gamosepalous, dentate calyx, free petals, one whorl of stamens which are split irregularly into several bundles (Fig. 470). The fruit is a _multilocular berry_ provided with a thick, tough, outer layer. The juicy pulp, which fills up the loculi and envelopes the seeds, is formed from many large-celled, juicy hair-structures which arise on the inner side of the walls of the loculi and by degrees entirely fill them up; the dissepiments remain thin, and form the partitions so easily separating from each other (Fig. 469). The seeds in many instances are remarkable for containing several embryos. The blade of the leaf is separated from the frequently winged stalk by a _node_ (and hence is a compound leaf with only the terminal leaflet developed?) (Fig. 468); in other genera, as _Triphasia_, there is a fully developed trifoliate leaf. Thorns are frequently developed.--~The species of this genus, which is a native of the warmer parts of S. E. Asia, are very hard to separate. The differences are found in the forms of the fruit, the leaves and the leaf-stalks, and in the number of stamens. _Citrus medica_, “Cedrat” (Ind.); _C. limonum_, “Citron,” “Lemon” (introduced into Italy in the 3rd to 4th century). OFFICINAL: the fruits and essential oil of Lemon. _C. aurantium_ from E. Asia, the Orange (introduced into Italy in the 14th century). _C. vulgaris_ (Fig. 468), Bitter Orange (introduced into Europe at the time of the Crusades); the unripe Bitter Oranges, and peel of the Bitter Orange is officinal; it is from the flowers of this species especially that the essence of Neroli is made. _C. limetta_, _C. bergamia_, Bergamot; essence of Bergamot is officinal. _C. decumana_, Pomalo, a native of the Islands of the Pacific. About 780 species; chiefly tropical.~

Order 4. =Burseraceæ.= Fruit a drupe; 1–5 stones. The bark,
as well as the other parts, contain strong aromatic resins
and balsams, and hence several species are used: the Myrrh
tree, _Commiphora_ (_Balsamodendron_) from Arabia and Africa;
OFFICINAL: Myrrha (_Commiphora myrrha_). Mecca-balsam from _C.
opobalsamum_, Arabia; E. Africa. The Incense-tree (_Boswellia_)
from the same parts of the globe and E. India. The incense of
_B. carteri_ is medicinal (Frankincense). The resin (Elemi) of
_Protium_-species is officinal, and is used technically for
varnish (S. Am.). Takamahaka-resin from _Elaphrium_ (S. Am.)
_Protium_ (_Icica_); _Amyris_ (1 carpel). 270 species; tropical.

Order 5. =Zygophyllaceæ.= The majority have opposite, pinnate
leaves with stipules. _Leaves without pellucid dots._ The
filaments have a scale on the inner side. The most important is
_Guaiacum officinale_ (West India), the wood (Lignum Vitæ) of
which is very hard and heavy, this wood and Gum-guaiacum are
officinal. Others have a peculiar repulsive smell and taste: the
Creosote shrub (_Larrea mexicana_) and _Zygophyllum simplex_.
_Tribulus terrester_ is a common weed in S. Europe. _Fagonia._
_Peganum harmala_ (South of Russia) yields a red dye.--110
species; especially in the Tropics; several species in sandy
deserts. _Nitraria._

Order 6. =Simarubaceæ.= This order is distinguished by the
abundance of _bitter_ substances which it contains (Quassine)
especially in the bark and the wood. The wood of _Quassia amara_
(Guiana, Antilles) is officinal; _Picraena excelsa_ yields
Jamaica Quassia; the bark of _Simaruba_, _Simaba_-species
and others is used. _Ailanthus glandulosa_ is a garden plant
(pinnate leaves, winged fruit).--110 species. Tropical.

Order 7. =Ochnaceæ.= Flowers diplostemonous, 5-merous. The
unilocular ovaries, which are individually free, project
considerably into the air around the gynobasic style; 1 ovule
in each loculus; the fruitlets are drupes. Shrubs; leaves
alternate, with stipules. _Ochna_; _Ouratea_.--160 species;
tropical; especially American.

Order 8. =Anacardiaceæ.= The ovary rarely contains more than 1
ovule, even though there be several loculi and several carpels;
in _Anacardium_ all the 10 stamens except one become suppressed.
Resin passages.--_Anacardium._ The most peculiar feature is the
development of the flower-stalk into a fleshy body about the
form and size of a pear (_A. occidentale_ from Trop. Am. and
_A. orientale_ from E. Ind.) which bears the kidney-shaped nut
(the so-called “Cashew-nut”) on its apex. _Mangifera indica_
(the Mango-tree, from E. Ind.) is cultivated in several tropical
countries on account of its delicious drupe. Similarly, species
of _Spondias_ (_S. dulcis_, Pacific Islands, _S. lutea_).
Several species of _Rhus_ are ornamental shrubs in this country,
for instance, _R. typhina_ (N. Am.), _R. cotinus_ (the Wig-tree,
the _barren_ flower-stalks of the panicles being feather-like
and hairy); _R. toxicodendron_ (Poisonous Sumach, from N. Am.)
is poisonous. Chinese galls are produced by the sting of a
leaf-louse (_Aphis chinensis_) on _R. semialata_ (China), and
Japanese wax is from the seeds of _R. succedanea_ (Japan).
Considerable quantities of Sumach (_R. coriaria_) are used in
tanning and as a black dye. OFFICINAL: the mastic resin of
_Pistacia lentiscus_ (the Mastic-tree, from the Mediterranean).
The fruits of _Pistacia vera_ (Syria) are edible; _P.
terebinthus_ and others yield turpentine.--450 species; tropical.

Order 9. =Icacinaceæ.= Flowers 4–5-merous; haplostemonous;
receptacle convex or cup-like surrounding the gynœceum; in
the (single) loculus of the ovary, 2 anatropous, pendulous
ovules.--200 species; tropical.

Family 16. =Aesculinæ.=

The essential characters of this family are in the main the same as those of the Terebinthinæ and Gruinales. The flowers are hypogynous, perfect, with free petals, 5-merous (S5, P5, typically A5 + 5, all of which, however, are not generally developed; in our native orders there are only 7–8 stamens), and most frequently a _3-merous, 3-locular gynœceum_ (less frequently 2 or 5 carpels with as many loculi). In each loculus there are usually only 1–2 ovules. A deviation from the preceding families is the frequent _zygomorphy_ of the flower, with, as a rule an _oblique_ plane of symmetry (Fig. 471). When a _disc_ is developed it is placed _outside_ the stamens. The majority have no endosperm (Fig. 473).--The members of the family are nearly all trees.

The family is closely allied to the Terebinthinæ, but unlike
this it never has aromatic properties, and differs also
in the position of the nectary, in the flowers, which are
often irregular with a reduction in the number of stamens,
and in the ovule which is usually ascending with micropyle
pointing downwards (the Terebinthinæ having the micropyle
turned upwards), etc. It is also related to Frangulinæ, the
Staphyleaceæ being the chief connecting link; but the Æsculinæ
generally have compound leaves.

Order 1. =Staphyleaceæ.= Leaves opposite, often compound.
Flowers regular, ☿, 5-merous in calyx and corolla, 5-stamened.
The stamens are placed _outside_ the nectary. Ovary syncarpous
or 2–3-partite with free styles. The capsule is thin,
bladder-like, 2–3-locular, opening at the apex, and has several
very hard seeds with a shining testa without aril. Endosperm.
_Staphylea pinnata_ (S. Europe) and _trifoliata_ (N. Am.) are
cultivated in gardens; they have white flowers in pendulous,
axillary racemes or panicles.--16 species.--_Staphylea_ is found
in the Tertiary of N. America.

Order 2. =Melianthaceæ.= Glaucous shrubs with scattered, pinnate
leaves, and large stipules. _Melianthus._--8 species; S. Africa.

Order 3. =Sapindaceæ.= Trees or shrubs, often climbing by tendrils (lianes with anomalous structure of the stem) and with compound leaves. The flowers, in most cases, are small, insignificant, and without scent, and in some polygamous and zygomorphic. S4–5, P4–5, A8 (less frequently 5–10) inside the nectary (disc); ovary generally 3-locular, with 1–2 ovules in each loculus (raphe ventral, micropyle turned downwards). Seed without endosperm, often with an aril. The embryo is often thick and curved (Fig. 473).

FIG. 471.--Diagram of the flower and of a scorpioid cyme.

FIG. 472.--Flower in longitudinal section.

FIG. 473.--Seed in longitudinal section.]

_Æsculus_ (Horse-Chestnut). Trees with opposite, digitate, dentate leaves without stipules; the inflorescence is composed of unipared scorpioid cymes arranged in a pyramidal panicle (termed a thyrsus). The flowers are irregular, with an _oblique plane of symmetry_ (through the 4th sepal, Fig. 471); there are 5 sepals, 5 free petals, of which the one lying between S^3 and S^5 is the smallest (see Fig. 471) and may be absent; stamens 7 (5 + 2), three being suppressed; gynœceum simple, 3-carpellary and 3-locular, with single style; of the two ovules one is ascending, the other descending (Fig. 472).--The fruit is a 3-valvate, sometimes spiny, capsule, with loculicidal dehiscence, the seed having a large hilum, a curved embryo without endosperm and united cotyledons (the radicle lies in a fold of the testa, Fig. 473). _Æ. hippocastanum_ (Greece, Asia), introduced into cultivation about 300 years ago; the majority of the other species, _e.g. Æ. pavia_, etc., several of which are frequently cultivated in gardens, are from N. America. ~The flower of the Horse-Chestnut is adapted for bees, whose abdomen touches the anthers or style when visiting the flower. The flowers are protogynous.~

The other Sapindaceæ have most frequently 4 sepals, 8 stamens,
various fruits (septicidal capsule, nuts with or without wings,
schizocarp), etc. _Serjania_, _Cardiospermum_, _Sapindus_,
_Koelreuteria_, etc. (about 118 genera, 970 species). The seeds
of _Paullinia sorbilis_ contain caffeine, and are used as “Pasta
guaranà,” in the North Western Brazils in the manufacture of a
common drink. _Nephelium_ (or _Euphoria_) _litchi_ (with edible
aril), and other species, from Asia.

Order 4. =Aceraceæ.= This order is so closely allied to the Sapindaceæ, that some authorities have classed it with them. The main difference is in the _regularity_ of the flowers, and the =2=-merous gynœceum (in abnormal cases several carpels occur).--They are trees, and, like the Horse-Chestnuts, have opposite leaves without stipules; in _Acer_ the leaves are palminerved, but imparipinnate in _Negundo_, a plant frequently cultivated in gardens. The flowers are often unisexual, polygamous (some species have ☿-, ♂-and ♀-flowers); sepals 5, petals 5 free, =stamens 8= (that is, 5 + 5, but the two median ones are absent) inside a large disc. Fruit a samara (schizocarp) with 2 _winged, nut-like_ fruitlets (Fig. 474). In each of the 2 loculi of the ovary are 2 ovules. Embryo _curved_, with thin, _folded_ cotyledons. Endosperm absent.--~The inflorescences are racemes with a more or less elongated main axis and terminal flower (which sometimes has 10 stamens); when the lateral branches are developed they are similar to the main axis. In some species both corolla and petal-stamens are suppressed. _Acer_ is pollinated by insects, _Negundo_ by the wind.--88 species; North Temperate zone. _Acer_ in the Tertiary from the Oligocene. The following are native plants: Maple (_Acer campestre_), Sycamore (_A. pseudoplatanus_, doubtful native). Important as avenue trees and timber. Sugar is obtained from the spring sap of the Sugar Maple (N. Am.).~

Order 5. =Malpighiaceæ.= A tropical (especially American) order
closely related to the Aceraceæ, having often the same form of
fruit (but 3-partite). Some species are lianes with anomalous
stem-structure. Leaves opposite. The flowers are regular or
obliquely zygomorphic (the plane of symmetry passing through
sepal 3), with S5, P5, A5 + 5, G3; 1 pendulous ovule in each
loculus. Important characteristics for identification are the
numerous grandular structures on the sepals. Peculiar 2-spined
hairs are found in some. _Malpighia_, _Bunchosia_, _Galphimia_,
_Tetrapterys_, _Heteropterys_, etc.--About 600 species.

Order 6. =Erythroxylaceæ.= Sepals 5, petals 5 (with a ligular
corona), 10 stamens in one bundle. Gynœceum 3-locular. Fruit
a drupe. Tropical (especially American) trees and shrubs, the
_Coca-plant_ (_Erythroxylon coca_) being best known. Its leaves
are considered by the inhabitants of Chile and Peru to be one
of the indispensable necessaries of life; they are chewed, and
possess intoxicating, exhilarating properties, and contain
the alkaloid cocaine, which is frequently employed as a local
anæsthetic.--103 species; chiefly in America.

Order 7. =Vochysiaceæ.= Trees; Trop. Am. 1 stamen.--140 species.

Order 8. =Trigoniaceæ.= Shrubs; Trop. Am.--30 species.

Order 9. =Tremandraceæ.= Polygalaceæ with regular flowers.--27
species. Australia.

Order 10. =Polygalaceæ.= Herbs or shrubs (some tropical species are lianes) with scattered (rarely opposite), simple and most frequently quite entire leaves, without stipules. The flowers are usually borne in terminal spikes or racemes, and are strongly zygomorphic (_the plane of symmetry being median_); they have 5 free sepals, the 2 _lateral ones_ of which (4 and 5 in Figs. 475, 476) are very large, _petaloid_, and frequently project on each side like the “wings” of a Pea-flower; petals 5, of which the two lateral ones are wanting or rudimentary (dotted on Fig. 475), and the _anterior_ “the _keel_” (Fig. 476 _c_) is large, hollow and boat-shaped, and frequently with a lobed or fimbriated edge (Fig. 476 _A_ and _B_, _c_); stamens 8, the two median ones being absent, all _united_ into a tube split along the back, which is also slightly united to the keel (the anthers, often 2 locular, _open by pores_, Fig. 476 _B_, _st_); the 2 median carpels form a bilocular ovary. 1 pendulous ovule in each loculus (Figs. 476 _C_, 475); capsule compressed with loculicidal dehiscence, rarely a nut. _Polygala_ (Milk-wort).

470 species; distributed over the whole globe (none Arctic).
OFFICINAL: the root of _P. senega_, from N. Am. Some are used as
ornamental plants.

POLLINATION. The flowers of _Polygala_ are pollinated by insects
(chiefly bees). The fimbriated processes of the anterior petal
support the insect when it alights. The anthers lie on each
side of the stigma in the pouch of the anterior petal; the apex
of the style is spoon-shaped, and immediately behind it is a
viscid stigmatic lobe. In reaching the honey the proboscis of
the insect must come in contact with the pollen and the viscid
stigma, by which it is rendered sticky; this ensures the pollen
adhering to the proboscis and so being carried to other flowers.

Family 17. =Frangulinæ.=

The plants belonging to this family, with very few exceptions, are trees or shrubs. The leaves are usually simple; stipules may be absent or present. The flowers in almost all the orders are _small, green or whitish_; they are _always regular_, 4-_or_ 5-_merous_ with 2–5 _carpels_, but never have more than 1 _whorl of stamens_, which in _Rhamnaceæ_ and _Ampelidaceæ_ are placed _opposite_ the petals (typically 5 + 5 or 4 + 4 stamens, of which however either the external or internal whorl is always wanting); hypogynous or slightly perigynous, in _Rhamnaceæ_ only strongly perigynous or epigynous; generally ☿; the calyx is inconspicuous; petals free or slightly united. Gynœceum simple; _ovary generally multilocular_; style short or entirely wanting. A _disc_ is nearly always developed in the flower, but is found sometimes inside the staminal whorl, sometimes outside it or between the stamens. The ovules are apotropous (anatropous with dorsal or ventral raphe).

Order 1. =Celastraceæ.= _Euonymus europæa_ (Spindle-tree) may be chosen as a type. It is a shrub with simple, opposite leaves and small caducous stipules. The small, greenish-yellow flowers, borne in regularly-branched dichasia, are regular, ☿, with 4 whorls, 4-(or 5-) merous in regular alternation. There is a _thick disc_ upon which the polypetalous corolla (imbricate in the bud) and the stamens are borne, with a slightly perigynous insertion. The style is short and thick; the ovary has 2 _erect_ ovules in each loculus. The fruit is a red, 4-valvate capsule with loculicidal dehiscence; the seeds are few in number, and have a large, red-yellow _aril_ (developed from the micropyle). Embryo green, in a large, fleshy, white endosperm. ~The dingy yellow flowers are generally visited only by flies and ants for the sake of the honey secreted by the disc, and while they run about on the flowers they touch the anthers and stigmas, now with one part of the body, now with another. The flower is protandrous. The stigmas are not developed till several days after the opening of the anthers.--_Celastrus_, _Cassine_, _Catha_, etc.~

38 genera; 300 species. Distributed over the entire globe, with
the exception of the colder districts, and especially in the
Tropics. Some are ornamental bushes (_Euonymus japonica_). The
leaves of _Catha edulis_ are used by the Arabs and Abyssinians
in the same way as those of _Coca_ by the Peruvians.

Order 2. =Hippocrateaceæ.= 150 species; tropical; chiefly
lianes. S5, P5, A3, G3. Anthers extrorse.

Order 3. =Aquifoliaceæ (Hollies).= The genus _Ilex_ forms almost the entire order. (175 species out of 180; especially from S. Am.) They are shrubs or trees with scattered, leathery, simple leaves (in _Ilex aquifolium_, spiny) with very small stipules. The flowers are small, white, and borne in few-flowered inflorescences in the axils of the foliage-leaves; they are most frequently unisexual and diœcious. There are 4–5 sepals, petals, stamens and carpels in regular alternation; the calyx and _corolla_ have their leaves _slightly_ connate; stamens slightly adnate to the corolla; the ovary is generally almost spherical with a thick, sessile stigma (Fig. 477). This order deviates especially from _Celastraceæ_ in the _absence of the disc_ and in having only 1 (_pendulous_) ovule in each of the 4 loculi of the ovary, and in having a _drupe_ with generally 4 stones. Embryo extremely small, at the apex of the large endosperm, with the radicle directed upwards.--~3 genera.--_I. aquifolium_ (Holly) principally on the coasts of European countries; from Norway to W. Denmark, and further westward. It is a common garden shrub with stiff, shining leaves and red fruits. Several South American species contain so much _caffeine_ that they may be used as a beverage in the place of tea (_I. paraguayensis_, Paraguay tea, or Maté). The Holly does not contain caffeine.~

Order 4. =Ampelidaceæ (Vines).= Shrubs with the stem swollen at the insertion of the petioles and climbing by _tendrils borne opposite the leaves_ (Figs. 478, 479). The leaves are scattered (generally 1/2), stalked, stipulate, frequently palminerved and lobed, divided or compound. The small, greenish flowers are generally borne in paniculate _inflorescences, whose position is the same as that of the tendrils_ (Fig. 478); they are hypogynous or slightly perigynous, ☿, with 4–5 sepals, petals, stamens (which, as in the Rhamneæ, are _opposite the petals_; Fig. 480 _A_, _B_) and 2 carpels. The calyx is very small, entire, or slightly dentate; corolla _valvate_, and in some falling off as a hood, since the individual parts remain united at the summit (Fig. 480 _A_). Between the stamens and gynœceum is situated an hypogynous _disc_, with 5 lobes alternating with the stamens (Fig. 480 _A_, _B_, _E_). In each loculus of the 2-locular ovary there are 2 _erect_ ovules (_E_); the style is short or wanting. The fruit is a _berry_. The embryo is small and lies in a horny, sometimes slightly folded (ruminate) endosperm (Fig. 480 _C_, _D_).

FIG. 478.--Branch with bunch of grapes.

FIG. 479.--Diagram of the position of leaf and tendrils. The
branch is divided into sections on the sympodial theory (the
successive generations, I, II, III, IV, are alternately white and
shaded); _k_ buds.

FIG. 480.--A Flower throwing off the corolla; _B_ flower after
the removal of the corolla; _C_, _D_ longitudinal and transverse
section of seed; _E_ longitudinal section of gynœceum; _s_ calyx.

FIG. 481.--Diagram of branch and position of leaves; _sl_
tendril; _lt_ the main axis; _ax_ stipules of the foliage-leaf
shown below; _g_ axillary-bud (the dwarf-branch); _v_ its
fore-leaf; _l_{1} l_{2}_ its first two foliage-leaves with
their stipules; _lt_{1}_ long-branch in the axil of _v_
(everything appertaining to this branch is entirely black);
_v_{1}_ the first leaf of this branch.]

_Vitis_ and _Ampelopsis_ (5-merous flowers); _Cissus_ (4-merous
flower); _Leea_ (without stipules, corolla gamopetalous). The
inflorescence in _Pterisanthes_ (E. Ind.) has a peculiar, flat,
leaf-like axis, on the edges of which ♂-flowers are borne, and
on the surface ♀-flowers.

The TENDRILS in Ampelidaceæ are modified branches, since they
bear leaves and may be abnormally developed as branches with
foliage-leaves, and finally the inflorescences are borne in
the position of the tendrils, and tendrils are met with which
are partly inflorescences. The explanation of the position
of the tendril, namely, right opposite the foliage-leaf but
without a subtending-leaf, has been much disputed. The relative
positions are as follows: in _Vitis vinifera_ the following
two kinds of shoots and relative positions are found (the
other species deviate in one or other particular), (_a_)
LONG-BRANCHES, which have 2 scale-leaves and a large number of
foliage-leaves with a divergence of 1/2; opposite the lowest
3–5 foliage-leaves no tendrils are found, then follow: 2
foliage-leaves with tendrils, 1 without a tendril, 2 with and
1 without, etc., with great regularity. Buds are developed in
the axils of the foliage-leaves (Fig. 479): these develop into
(_b_) DWARF-BRANCHES, which commence with 1 laterally-placed
scale-leaf (fore-leaf; Fig. 481 _v_) succeeded by several
foliage-leaves with a divergence of 1/2 (in a plane at right
angles to that of the mother-shoot), but the whole shoot is
extremely small, and often dries up and drops off in the
autumn, so that only the scale-leaf, _v_, with the bud (Fig.
481 _lt_{1}_) in its axil remains. This bud in the following
year developes into a new long-branch, and since its leaves
lie in a plane at right angles to that of the dwarf-branch,
their plane coincides with that of the long-branch from which
it is developed (the grandmother axis).--The tendrils no doubt
may most correctly be regarded as the modified main axis which
has been pushed aside by a lateral branch. The branches are
then sympodia, whose successive shoots bear alternately 1
and 2 foliage-leaves: thus, on the figure there are portions
altogether of 5 shoots (I.-V.), the 1-leaved ones are shaded,
the 2-leaved ones are white. The following facts however are
adverse to this theory: (1) the first leaf on an axillary bud
is then situated 180° from the subtending leaf (_e.g._ the
lowermost shaded leaf, Fig. 479, 180° from the lowermost white
leaf), whilst the rule in the Dicotyledons is that it is placed
only about 90° to one side. (2) The buds (Fig. 479 _K_) from
which the dwarf-branches develop, must then be accessory and
sister-buds to the sympodial shoots, but their first leaves have
a different relative position to this, which is very peculiar,
and a still more remarkable fact is that the buds, _K_, etc. are
similar in structure and present in _all the axils_; thus we
_only_ find accessory buds in the cases where no tendrils are
opposite to the leaves, and the main bud must then be considered
to be suppressed. (3) The development proves that the tendrils
arise on the side of a vigorous growing-point of the stem or by
its division, and do not develop, as might be expected, from
the apex of the shoot. But these relations however, find their
analogues and are all capable of explanation, whereas other less
natural modes of explanation are opposed to them.

435 species; especially in the Tropics; they are rarer in
America. In N. Am. some _Vitis_-species and _Ampelopsis
quinquefolia_ are found. _Vitis vinifera_ is supposed to have
originated in the districts East and South of the Caspian Sea.
Wine is obtained from _Vitis_-species, especially _V. vinifera_,
and “raisins,”--(the name “currants,” given to a special variety
with small, seedless fruits, is derived from Corinth).--The
species of _Ampelopsis_ (Virginian Creeper) are cultivated as
ornamental plants.

Order 5. =Rhamnaceæ.= _The stamens are placed opposite the petals_ as in the Ampelidaceæ (Fig. 482), but the flowers are _much more perigynous or entirely epigynous_. The trees and shrubs belonging to this order have simple, most frequently penninerved leaves with stipules; frequently thorny (modified branches). The flowers are inconspicuous, sometimes unisexual (Fig. 482), and have 5 (-4) sepals, petals, stamens, and generally 3 (2–5) carpels. The calyx has _valvate_ æstivation. The petals are very _small_ (generally less than the sepals), often spoon-like, hollow, and embracing the stamens; _a disc covers the inner surface of the thalamus_ or the base of the style in the epigynous flower; gynœceum simple, with one style and one _erect ovule in each loculus_. The fruit is most frequently a _drupe_. The embryo is large, often green or yellow, with endosperm.

_Rhamnus_ (Buckthorn) has a juicy drupe with 3 (2–4) stones, surrounded at the base by the persistent portion of the receptacle; the disc is thin. _R. cathartica_ (common Buckthorn): diœcious, with opposite, serrate leaves. _R. frangula_ (Alder Buckthorn): flowers ☿, with scattered, entire leaves.--~_Ceanothus_ (N. Am., with richly-flowered inflorescences and a fruit closely resembling that of the Euphorbias). _Phylica_, _Pomaderris_ (Austr., fruit a capsule). _Zizyphus_, _Paliurus_, _Colletia_ (S. Am.) are thorny shrubs; _C. spinosa_ has thorny shoots with small, caducous leaves; the seedling has normal foliage-leaves. Others climb by tendrils as in the Ampelidaceæ, _e.g._ _Gouania_.~

475 species, 40 genera; chiefly in temperate and tropical
climes. Some are medicinal plants, the bark and fruit
having purgative properties (the bark of _Rhamnus frangula_
and “Cascara Sagrada” from the bark of _R. purshiana_ are
officinal). The fruits and seeds of others are edible, for
example, the fruits of _Zizyphus lotus_, _Z. vulgaris_, _Z.
spina Christi_, etc. Green and yellow _dyes_ are obtained from
the fruit of _R. cathartica_, _infectoria_ and others (Avignon
grain). _Ceanothus-_, _Rhamnus-_ and evergreen _Phylica_-species
are ornamental shrubs.

Family 18. =Thymelæinæ.=

Exclusively trees or shrubs with simple, entire, scattered leaves without stipules. They have a _strongly perigynous_, regular, _4-merous_ flower. The receptacle (often coloured) envelopes a simple gynœceum formed of =1= _carpel_ and with, in most cases, =1= ovule, bearing on its edge 4 (or 5) petaloid sepals and, but rarely at the same time, small, scale-like petals. The corolla is most frequently entirely wanting (and hence these plants were formerly reckoned among the Monochlamydeæ); frequently only one of the 2 whorls of stamens, which are situated on the inner side of the edge of the receptacle, is developed. The fruit is most frequently a _1-seeded_ berry or drupe, or a nut which may be falsely berry-like, the partly persistent receptacle being fleshy and enveloping it.

This family appears the most nearly allied to the Frangulinæ,
especially the Rhamnaceæ, and may be considered as a further
development of these in the direction of the petaloid
development of the receptacle and reduction of the corolla and
gynœceum, which in this instance only consists of one carpel.
Another deviation is that both the whorls of stamens are
present, while one of these is always wanting in Frangulinæ.
They also appear to be related to the Lauraceæ (see page 391).

Order 1. =Thymelæaceæ.= The flowers are most frequently ☿ (Fig. 483). The receptacle is high, generally tubular, coloured, and bears on its edge the 4-(or 5)-merous calyx, with imbricate æstivation. The corolla is wanting or is represented by small scales. The stamens are situated on the inside of the receptacle, and number 4 + 4 (or 5 + 5); stigma capitate. 1 _pendulous ovule_ (Fig. 483 _B_), the _radicle pointing upwards_. The fruit is most frequently a berry. ~A disc is sometimes developed. Endosperm wanting or very slight.~

_Daphne_ (Spurge-Laurel, Fig. 483) has a deciduous receptacle, often coloured; sepals 4; petals absent; stamens 4 + 4. Berry.--_Gnidia_ (corolla); _Pimelea_ (2 stamens); _Thymelæa_; _Passerina_ and others.

400 species; chiefly in the warm, sub-tropical zone, especially
the Cape and Australia. Only _Daphne_ and _Thymelæa_ in
Europe. In the fruit and bark of some, for example _Daphne_,
pungent, burning and poisonous properties are found. The bark
of _D. mezereum_ (native and cultivated) and _D. laureola_ is
officinal. A specially tough bast is found in some species, for
example _Lagetta lintearia_ (Lace-tree, Jamaica), which is used
in weaving. Some are cultivated in gardens as ornamental shrubs,
especially species of _Daphne_.

Order 2. =Elæagnaceæ.= Shrubs or trees, which are easily recognised by the covering of _peltate hairs_ found upon almost all parts of the plant, causing them to assume a _silvery_ or rusty-brown appearance. Stipules are absent; the leaves are simple, most frequently scattered. Flowers (Figs. 484, 485) frequently unisexual. The sepals are valvate, 2-4; the _corolla is wanting_; _stamens_ 4 + 4 or 0 + 4. The ovule is _erect_ and _the radicle turned downwards_ (Fig. 486). The fruit is a _nut_, but becomes _a false fruit_, being surrounded by the persistent receptacle or the lower part of it, and thus assuming a berry- or drupe-like appearance (Fig. 486). Endosperm insignificant.--_Shepherdia_ (opposite leaves) has 4 sepals, 4+4 stamens, as in _Daphne_. Diœcious.--_Elæagnus_ (Silver-leaf) is ☿, has 4–6 sepals, and 4–6 stamens alternating with them. _Hippophaë_ is diœcious; it has 2 sepals and 4 stamens in the ♂-flower (perhaps properly speaking 2+2 stamens); thorny (stem-structures).

16 species; especially ornamental shrubs, _e.g. Elæagnus
argentea_, _angustifolia_; _Hippophaë rhamnoides_ and
_Shepherdia canadensis_. Northern Temp.

FIG. 484.--Floral diagram.

FIG. 485.--Longitudinal section through the flower.

FIG. 486.--Longitudinal section through the fruit.]

Order 3 (?). =Proteaceæ.= This order has its chief centre in the dry regions of Australia (6/10–7/10 of about 1,000 species), a smaller number in S. Africa (2/10–3/10). a few species in S. Am. Trees or shrubs, leaves generally scattered, without stipules, and more or less dry, leathery, evergreen, and often of very different forms on the same plant (undivided, compound, etc.) The flowers are ☿ (rarely unisexual), and _4-merous_ in the single, petaloid perianth and in the staminal whorl; 1 carpel; sometimes zygomorphic. The perianth-leaves are generally almost free, with _valvate_, æstivation, often leathery. Small scales alternating with the perianth are often found at the base of the ovary. The stamens generally have extremely short filaments, and are situated opposite, sometimes quite on the tip of the perianth-leaves, in a spoon-like groove. The gynœceum is 1-locular, has 1–several ovules, and is often raised on a stalk-like internode. The fruit is a follicle or nut. The seeds, most frequently winged, have no endosperm.--_Protea_, _Manglesia_, _Hakea_, _Banksia_, _Grevillea_, etc. 50 genera; about 1,000 species. Several species are cultivated in our conservatories for the sake of the flowers, which are beautifully coloured and arranged in crowded inflorescences. Protandrous. It is doubtful whether they were existent in Europe in the Tertiary Period. The true systematic position of the order is doubtful. They are related to the Leguminosæ and Rosifloræ, but more closely no doubt to the two preceding orders.

Family 19. =Saxifraginæ.=

The flower is generally perfect, regular and polypetalous, usually _perigynous_ or _epigynous_, _eucyclic_ and 5-merous; most frequently S5, P5, A5 + 5 or 5 + 0 and G=2=-5, but other numbers are found, especially 4; the flowers are very frequently obdiplostemonous. The calyx is sometimes large and the corolla small; the carpels in some are entirely free, in others more or less united. Endosperm is found in the majority. ~The hypogynous forms approach the Cistifloræ, the others the following families, especially the Rosifloræ. This family is not, upon the whole, so well defined and natural as most of the others. The Saxifragaceæ proper, approach very near to the Rosaceæ, especially _Spiræa_, and form a transition to it. The forms with opposite leaves, as _Philadelphus_, etc., approach the Myrtifloræ, just as the Escalloniæ appear to be closely allied to Bicornes, especially _Vacciniaceæ_. Finally through _Pittosporaceæ_, they pass over to the Frangulinæ. The family terminates in very reduced forms, on the one hand in the arborescent orders with crowded inflorescences, on the other perhaps in the very remarkable order _Podostemaceæ_.~

Order 1. =Crassulaceæ.= Nearly all are herbs or small shrubs with round, succulent branches and scattered, _fleshy_, often more or less round leaves, which are very rarely incised, and never have stipules. The flowers are generally borne in dichasia or unipared scorpioid cymes, which again may be arranged in racemes, umbels, etc.; they are regular, ☿, hypogynous or perigynous, and most frequently have free sepals and petals (gamopetalous corollas with sessile stamens are found in _Cotyledon_, _Bryophyllum_, _Echeveria_, and others); the floral formula is Sn, Pn, An + n, Gn, where n may have very different values, partly depending upon the size of the flower (_e.g._ 4–7 in _Sedum_, Fig. 487; 6–30 in _Sempervivum_; 4 in _Rhodiola_, _Bryophyllum_, and _Kalanchoë_; 5 in _Echeveria_, _Umbilicus_, _Cotyledon_). The carpels are _free_ and are _placed opposite the petals_ (Fig. 487). Fruit a _syncarp composed of follicles_ containing many, small seeds without endosperm. Outside each carpel is found a small, nectariferous scale (Fig. 487). ~The northern genus, _Rhodiola_, is diœcious. The petal-stamens are wanting in some (_Crassula_, _Bulliarda_, and others). The floral-leaves are very often displaced upon their axillary branches. A multicarpellary gynœceum also occurs.~

_Sedum_ (Stonecrop) is generally 5-merous with 10 stamens; _Sempervivum tectorum_ (House-leek), 12-merous, and with 24 stamens. ~The leaves of _Bryophyllum calycinum_ very readily form buds, and also frequently exude water from the edges.~

485 species; especially Temp. (Cape, Europe). Principally used
as ornamental plants.