Chapter II: ACROGYNÆ. The apex of the stem or of certain branches is adapted (11)

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.

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.

Family 23. =Myrtifloræ.=

The leaves are most frequently _opposite_, _simple_, _entire_ (rarely dentate), and _exstipulate_. The flowers are _regular_ and _epigynous_ (perigynous in _Lythraceæ_ and a few others), ☿, polypetalous; the number of members in a whorl is generally 4 or 5 (S, P, A, or most frequently A 2, G), but sometimes it becomes (_e.g._ Myrtles and _Lythraceæ_) very large in the andrœcium by splitting, and in the gynœceum also is often different. (When suppression takes place it is principally in the corolla and petal-stamens.) In nearly all instances the calyx is _valvate_. Gyncœceum multicarpellary, multilocular, with only one _style_ (except _Haloragidaceæ_). In the majority the ovules are situated on an axile placenta in the multilocular ovary. _Endosperm is wanting_ in the majority.--~Less important exceptions: _Rhizophoraceæ_ and _Gunnera_ have stipules. _Haloragidaceæ_ have several styles and endosperm. _Rhizophora_ also has endosperm.~

Order 1. =Lythraceæ.= _Hermaphrodite_, _perigynous_ flowers which are _most frequently =6=-merous_, viz. S 6 (often with a _commissural_ “_epicalyx_,” Fig. 519 _c_), one segment posterior, P 6, A 6 + 6 or 6 + 0 and G =2–6=, forming a 2–6-locular ovary with many ovules in the loculi, style single, and capitate stigma. The _gynœceum is free_ at the base of the tubular, or bell-shaped, _thin_, strongly veined receptacle, which bears the other leaf-whorls on its edge and inner side. Fruit a capsule. No endosperm.--To this order belong both herbs, shrubs and trees. The branches are frequently square, the leaves always _undivided_, _entire_, and without stipules, or with several very small stipules, and often opposite. The calyx is valvate. The flower is regular (except _Cuphea_) and frequently large and beautiful. The stamens are generally incurved in the bud, and the petals irregularly folded.

_Lythrum_ (Loose-strife). The flower is diplostemonous and 6-merous, with a long, tubular receptacle with epicalyx-teeth (Fig. 519 _c_). The 12 stamens are arranged in two tiers on the inner side of the receptacle. The gynœceum is bicarpellary. ~The flowers are borne in small dichasia in the leaf-axils, and their number is increased by accessory inflorescences beneath the main inflorescence.--The native species, _L. salicaria_, is trimorphic (long-styled, mid-and short-styled forms, Fig. 520). Cross-pollination is chiefly effected by humble-bees and bees, which seek the nectar formed at the bottom of the receptacle. Other species are only dimorphic, or even monomorphic.~--Closely allied are, _Nesæa_, _Diplusodon_, _Lagerstrœmia_, and _Cuphea_, whose flower resembles that of _Lythrum_, but is zygomorphic. In _Cuphea_ the receptacle is oblique and at the back prolonged into a _spur_, in which the nectar, secreted by a gland situated behind the ovary, is collected; the calyx and corolla gradually become reduced in size toward the anterior side of the flower; the reverse, however, is the case with the 11 stamens (the posterior one is absent); the posterior loculus in the bilocular ovary is sometimes barren; the fruit, when ripe, dehisces along the posterior side, the ovary as well as the wall of the receptacle being ruptured by the placenta, which expands and projects freely. ~The flowers stand singly in the centre of the stem, between the pairs of leaves. This may be explained as follows: of the two foliage-leaves in each pair, one supports a foliage-shoot, the other a flower; the foliage-shoot remains in the axil, but the flower is displaced through the length of an entire internode to the next pair of leaves, and then assumes a position between these two leaves. All foliage-shoots stand in two rows, the flowers in two other rows.~

_Peplis_ (Water-purslane), a small, annual plant, with thin,
bell-shaped receptacle without projecting nerves. The small
flowers have no petal-stamens, and often also no corolla; fruit
indehiscent.--_Ammannia_ is closely allied to it.

365 species; 30 genera; mostly in the Tropics, and more
especially S. Am.--Some yield _dyes_, _e.g._ _Lawsonia inermis_
(cultivated in Africa and Asia) and _Lagerstrœmeria indica_;
some contain tannin; others are ornamental plants, especially in
gardens in warm countries.

Order 2. =Blattiaceæ.= 12 species. Tropical Asia and Africa.
Trees. Formerly included with _Punica_, but best placed as an
independent order.

Order 3. =Melastomaceæ.= A very natural and very large order
(150 genera; 2,500 species), its home being chiefly in tropical
S. America, especially the Brazils (termed by Schouw “The
kingdom of Palms and Melastomaceæ”). There are both herbaceous
and arborescent species, which are easily recognized by the
opposite or verticillate, simple leaves which have (with the
exception of a few heather-like species) 3–5–7–9 curved veins
proceeding from the base of the leaf, and connected very
regularly by closely parallel, transverse veins. The flower
is perigynous or epigynous; its type is that of the Onagraceæ
(4–5-merous; 1 whorl of sepals, petals and carpels, 2 of
stamens); the calyx is valvate, the corolla is twisted (to
the left) in æstivation; the stamens are very characteristic;
in the bud they are geniculate; the anther opens in the often
long, beak-like, prolonged point, with 1, less frequently with
2 pores, and has generally ear-like appendages at its base.
The fruit is a berry or capsule. These large and beautiful
flowering-plants play a very important part in South American
landscapes; otherwise they are of slight importance (a few are
cultivated in conservatories, _e.g._ _Centradenia_, _Medinilla_,
_Lasiandra_, _Tibouchina_, _Miconia_, etc.).

Order 4. =Œnotheraceæ= (or =Onagraceæ=). The flowers are arranged in racemes or spikes, ☿, epigynous, regular, polypetalous, _=4=-merous in all 5 whorls_ (1 whorl of sepals, petals and carpels, 2 of stamens); 2–3–5–6-merous flowers are less frequent; _the calyx is valvate_, the _corolla twisted_ in æstivation (the left edge being covered). Gynœceum simple with multilocular ovary; the _style is undivided_, filiform, and bears a capitate or 4-partite stigma; endosperm wanting; embryo straight.--The majority are herbs, especially water- and marsh-plants; several are shrubs. No essential oils. The leaves are alternate or opposite, always single, and without (or with very small) stipules. ~The odourless flowers sometimes have a coloured calyx. In some instances (_e.g._ _Œnothera_, _Fuchsia_) the receptacle is prolonged more or less beyond the inferior ovary, and finally falls off. The stamens are obdiplostemonous (carpels epipetalous); the petal-stamens are sometimes suppressed. The anthers in some genera are divided into storeys. The well-pronounced, triangular pollen-grains are connected together by viscous threads. Small stipules are sometimes found, _e.g._ _Fuchsia_, _Lopezia_.~

=A.= =Fruit a capsule.= _Œnothera_ (Evening Primrose) is 4-merous, has 8 stamens, a tubular receptacle, and an oblong capsule with loculicidal dehiscence leaving a centrally placed column, bearing the seeds.--_Epilobium_ (Willow-herb) deviates from _Œnothera_ especially in the seeds being hairy (at the chalazal end of the seed).--_Chamænerium_ is a Willow-herb with zygomorphic flowers.--~The following may be included here: _Clarkia_, _Eucharidium_ (an _Œnothera_ with 4 stamens and 3-lobed petals), _Godetia_ and _Boisduvalia_, _Jussiæa_ (dehiscence septicidal), _Isnardia_ (petal-stamens absent, sometimes the petals also).--_Lopezia_ has a peculiar, zygomorphic flower (Fig. 521); one of the four sepals is bent forwards and the other 3 backwards; the posterior petals are narrower than the 2 anterior ones which are turned obliquely backwards and bent like a knee, with a greenish nectary at the bend; 2 stamens, one only fertile (the posterior), while the anterior is barren, petaloid, and spoon-shaped; both are sensitive, which is essential for pollination. In Fig. 521, _a_ represents an early stage, in which the stamen and style lie concealed in the staminode; _b_ is the ♂ stage, the stamen projects from the centre of the flower; _c_, the ♀ stage, the style occupies the place of the stamen.~

=B.= =Fruit a berry.= _Fuchsia_ generally has a coloured calyx and tubular receptacle; the corolla may be wanting.

=C.= =Fruit a nut.= _Circæa_ (Enchanter’s Nightshade) has a 2-merous flower (S2, P2, A2 + 0 [petal-stamens are wanting], G2). The flowers are borne in racemes without bracts.--_Gaura._

=D.= =Fruit a drupe.= _Trapa_ (Horn-nut); a peculiar aquatic plant; the submerged stem has long internodes and lanceolate leaves, falling off at an early period, but at each node are found 4 long roots with thin, lateral roots (sometimes erroneously regarded as leaves) borne pinnately; the stem reaching the surface of the water, bears a rosette of rhombic foliage-leaves, with large, inflated stalks containing air, and forming the floating apparatus of the plants. In the axils of the leaves (as in _Gunnera_) 8 small, stipular structures are present. The flowers are solitary in the axils of the foliage-leaves (S4, P4, A4 + 0, G2), _semi_-epigynous. There is an 8-lobed, crenate disc on the free portion of the ovary; one ovule in each loculus. The fruit is a _drupe_ with 4 (or 2) prominent horns (the persistent sepals), which after the pulp has decayed away bear a series of hooks turned downwards on each side, _i.e._ sclerenchymatous bundles which formerly lay concealed in the pulp of the sepals. ~The germination is peculiar: one of the cotyledons is large, and its thick extremity remains in the fruit, the other however is small and is pushed out at the apex of the fruit together with the radicle and plumule; the development of the root soon ceases, and the plumule usually grows into a stem entirely without branches, similar to the one described above, only that 1–2 precisely similar shoots arise in the axil of each cotyledon, so that each embryo produces 3–5 shoots.--_Trapa_, by its mode of life, its 1-seeded fruit, etc., forms a transition to _Haloragidaceæ_.~

The large-flowered forms are adapted for insect-pollination and
are often protandrous, the small-flowered ones are homogamous
and may pollinate themselves. _Œnothera_ is adapted for
hawk-moths and bees.--330 species; especially in temperate
climates, chiefly in the Northern Hemisphere. _Epilobium_,
_Circæa_ are natives of this country; _Trapa_ is extinct in this
country, it has been found in a semi-fossilized condition near
Cromer and in bogs in Denmark, and existed in Sweden until a few
years ago; _Œnothera_ has been introduced from N. Am.--A number
of N. Am. species are grown as ornamental plants in our gardens.
The seeds of _Trapa natans_ are edible, and used as food in
China.

Order 5. =Haloragidaceæ.= This is a reduced form of the Œnotheraceæ, and principally differs from these in the presence of _endosperm_ and _free styles_. _Only 1 ovule in each loculus._--84 species distributed over the entire globe; the majority are aquatic plants. The most advanced type is _Myriophyllum_ (Water-Milfoil), with a regular, epigynous flower (S4, P4, A4 + 4, G4), most frequently _diclinous_ (monœcious); the fruit is a _2–4-partite schizocarp_. Aquatic plants, most frequently with pectinate, pinnate leaves.--_Haloragis._--~_Gunnera_ (a dozen species from the Southern Hemisphere) forms the next step in the reduction. Large, scattered, rough-haired, and softly-spined leaves, with small flowers in crowded inflorescences. The flower, when most complete, has S2, P2, A2 (petal-stamens) and G2, forming an inferior, unilocular ovary with 1 ovule. It is remarkable for the great number of stipules placed in transverse rows in the leaf-axils, for the peculiar glandular organs, and for the colonies of _Nostoc_, which are found embedded in the cortex as a kind of parasite.~--The simplest form is _Hippuris_ (Mare’s-tail) with an extremely small, crenate or entire calyx, without corolla, and with only one stamen and one carpel, forming an inferior, unilocular ovary with only one ovule. Fruit a drupe with thin pulp. ~It is an aquatic plant with creeping, sympodial rhizome, and erect unbranched shoots, bearing numerous small, verticillate leaves. The small flowers are situated singly in the leaf-axils.~

Order 6. =Rhizophoraceæ.= Tropical trees or shrubs (50 species,
the best known being _Rhizophora mangle_, Mangrove) which grow
gregariously, especially along the banks of rivers and by
sea-coasts, where the water is quiet and brackish, and where
they form the so-called Mangrove-swamps. Aerial roots are formed
on the stems and branches (Fig. 522 _A_). The seeds germinate
in the fruit, which by arrest contains only one seed (Fig. 522
_B_), before it is detached from the tree. The radicle projects
considerably from the seed, and hangs down freely in the air;
when the embryo is finally detached from the mother-plant,
the separation is effected by the hood-like cotyledon, which
entirely envelops the plumule, becoming detached from the rest
of the embryo, which falls down, while the hood-like cotyledon
remains enclosed in the fruit. The embryo, after it has fallen,
strikes root, and continues growing in the undisturbed mud
under the trees, or perhaps it may first be drifted about by
the water, being well adapted for this by its peculiar, tough
nature, and large, intercellular spaces.--It may also further
be remarked that the anther is divided into a number of small
loculi. The leaves are stipulate. The endosperm projects from
the micropyle, growing out from the base of the seed, and thus
serves as an organ of suction to convey nutriment to the embryo
from the mother-plant.

Order 7. =Combretaceæ.= Trees and shrubs, partly lianes.
An inferior, unilocular ovary with few pendulous ovules.
_Conocarpus_ and _Laguncularia_ form, in conjunction with
the species of Rhizophoraceæ, the tropical Mangrove-swamps.
_Terminalia._--280 species; Tropics.

Order 8. =Myrtaceæ (Myrtles).= The plants belonging to this order are shrubs or trees, the majority being easily recognised by the vegetative characters. The leaves, for instance, are most frequently opposite, without stipules, undivided and entire, parchment-like or leathery, evergreen, _aromatic_, finely dotted by _pellucid glands containing essential oils_; the venation is penninerved with a nerve just inside and running parallel to the edge of the leaf. The flowers are regular, epigynous (Figs. 523, 524, 525) and ☿, most frequently =4-= or 5-merous in the calyx and corolla, with _many_ stamens (by splitting, so that they are often in several distinct bundles) and an ovary with one style, formed of 2–5–many carpels; the receptacle is most frequently united for its entire length with the ovary. The fruit varies, but is _most frequently a berry_. The embryo is thick, often curved, with united cotyledons; no endosperm.

=1.= MYRTEÆ, MYRTLE GROUP. Chiefly American, though some are found also in Africa and Asia. The fruit is a _berry_ with generally 2–5 loculi in the ovary, and many ovules in each.--_Myrtus_; _Eugenia_ (the petals fall off together as a hood in the Clove, _E. caryophyllata_, Figs. 523, 524); _Myrcia_; _Jambosa_; _Amomis_; _Psidium_, etc.

=2.= PUNICEÆ, POMEGRANATE GROUP. Only 2 species (_Punica granatum_; from Persia, Afghanistan), differing in several respects from the typical form of the Myrtaceæ. The leaves are generally _opposite_, without glands and marginal veins. The receptacle, calyx and corolla are red; the latter 5–8–(generally 6-) merous. Calyx valvate and corolla folded as in Lythraceæ, stamens also and epicalyx as in this order. The most characteristic feature is the inferior, spherical berry, with dry pericarp, formed from two whorls of carpels in two tiers (Fig. 525); the interior whorl, which is also the lower, has 3 carpels, and the placentæ are situated in the inner angles of the 3 loculi; the external whorl is 5-merous, and the placentæ have originally the same position in the inner angles of the loculi, but their position is changed to the outer side of the loculi owing to the growth of the wall of the ovary, which takes place early, causing the carpels to become, as it were, turned inside out, so that the part which was turned downwards is turned upwards, and the part which was turned inwards becomes turned outwards (as in _Mesembrianthemum_). The edible part of the fruit is the _fleshy testa_, as in _Ribes_. The cotyledons are rolled together spirally.

FIG. 523.--Flowers (nat. size).

FIG. 524.--A bud (“clove”), long. sec. (mag.).]

=3.= LECYTHIDEÆ. The majority are South American. The leaves are scattered, without pellucid glands, and frequently dentate. The flowers are zygomorphic. The woody fruits are either indehiscent, or open by a lid. To this belong: _Bertholletia_ (_B. excelsa_), the seeds well known as “Brazil-nuts,” _Lecythis_ (Sapucaia-nuts from _L. ollaria_), _Barringtonia_.

=4.= LEPTOSPERMEÆ. Almost entirely from Australia and the East Asian and Pacific Islands. The fruit is a _capsule_. The leaves are scattered, and in some placed edgewise by the twisting of the leaf-stalks.--_Eucalyptus_, the Australian Gum-tree; the calyx falls off like a lid (Figs. 526, 527). Some of the species attain gigantic heights, _E. amygdalina_ 140–150 m. with a diameter of 8 m. The leaves in _E. globulus_ are opposite and dorsiventral on the young plant; on the older scattered, placed edgewise by the twisting of the leaf-stalk, and isolateral; _Metrosideros_, _Calothamnus_ (stamens distinctly polyadelphous), _Melaleuca_, _Leptospermum_, _Callistemon_ (the flowers are borne in spikes whose axis continues to grow after flowering, thus several zones of fruits may be seen on the same branch).

FIG. 526.--Long. sect. of flower.

FIG. 527.--Flower opening.]

=5.= CHAMÆLAUCIEÆ. Australian shrubs with heath-like appearance; they differ from the other Myrtaceæ in having a unilocular ovary with few, basal ovules, and a 1-seeded _nut_. The sepals are often pappus-like, and divided into many bristles.--_Chamælaucium_, _Darwinia_, etc.

This large order (2,100 species) is confined almost entirely to
the Tropics, being found principally in America and Australia.
In Europe, only _Myrtus communis_.--Several are useful on
account of the large quantity of _volatile oils_ (contained
in internal glands): the flower-buds (“Cloves”) of _Eugenia
caryophyllata_ (the Moluccas, cultivated in the Tropics, Figs.
523, 524); the unripe, dry berries (“Pimento”) of _Myrtus
pimenta_ (_Pimenta officinalis_, W. Indies); Cajeput oil is
extracted from _Melaleuca minor_ and _leucadendron_ (East
Asian Islands). _Eucalyptus globulus_ (Australia) has of late
years become well known on account of its rapid growth, its
hard wood, and its antipyretic qualities; it is cultivated on
swampy soils, which it helps to drain.--OFFICINAL: “Cloves,”
and the cork of both stem and root of _Punica granatum_.
Several have EDIBLE FRUITS, such as _Psidium guyava_ (Guava,
var. _pomiferum_ and _pyriferum_, Am.), _Eugenia cauliflora_
and others, _E. jambosa_, _Punica granatum_ (the Pomegranate),
etc. EDIBLE SEEDS (with abundance of _fatty oil_): “Brazil
nuts” from _Bertholletia excelsa_ (Trop. S. Am.). “Bay-rum”
is extracted from the leaves and fruits of the Bayberry-tree
(_Pimenta acris_, W. Ind.); Guava-rum from the berries of
_Eugenia floribunda_. _Tannin_ is found in large quantities
_e.g._ in _Punica_. _Gum_ is formed by many Australian Eucalypti
(“Gum-trees”). ORNAMENTAL PLANTS cultivated in this country are:
_Myrtus communis_ (Mediterranean), several in conservatories,
especially the Australian Leptospermeæ, Eucalyptæ and others.

Family 24. =Umbellifloræ.=

The flower is regular, ☿, and _completely epigynous_, 5- or 4-merous, with =1= whorl of stamens and 5–2 carpels. _Sepals very small, tooth-like._ The _corolla is polypetalous, most frequently valvate in æstivation_ (least pronounced in the Umbelliferous plants). Round the base of the styles, which are generally free, there is an _epigynous_ (undivided, or divided) _nectar-disc_ (“stylar-foot”: Figs. 528 _B_, _C_, _D_; 539); the number of loculi in the ovary equals that of the carpels; _only =1= pendulous (anatropous) ovule_ (Fig. 528 _C_) _in each loculus_. Endosperm copious (Fig. 528 _D_). To this must be added that the inflorescence in the majority of cases is an _umbel_ or a capitulum, especially in the _Umbelliferæ_ and _Araliaceæ_. Stipules are absent, but most frequently the base of the petiole forms a large sheath.

The Umbellifloræ are on one side so closely allied to the
Frangulinæ, especially Rhamnaceæ, that they may perhaps be
regarded as the epigynous continuation of this family. On
the other hand, the similarities to the Rubiales, especially
those between Cornaceæ and Sambuceæ, are so great that there
is scarcely any character to distinguish them except the
polypetalous corolla of the former and the gamopetalous corolla
of the latter. Whether this is more than a merely analogous
resemblance, and if not, whether the Cornaceæ at least should
not be included in the Rubiales, must be left in abeyance.--The
sepals are very small, as is generally the case in epigynous
flowers.

Order 1. =Cornaceæ.= The majority of the species are shrubs with solid internodes, _opposite_ (rarely scattered) leaves, which are _simple_, _entire_ (rarely incised), penninerved, _without_ stipules or large sheaths; flowers _=4=-merous_ (most frequently S4, P4, A4, G2), borne in dichasia which are either collected into corymbs (_e.g._ _Cornus sanguinea_), or in closely crowded umbels or capitula (_Cornus mas_, _C. suecica_), in which latter case there is often a _large_, leafy, or coloured, most frequently 4-leaved _involucre_ round the base of the inflorescence; the _style is undivided_, with lobed stigma; the raphe of the ovule is turned _outwards_. The fruit is a _berry_ or a _drupe_, with a 1–4-locular stone or 2 free stones.

_Cornus_ (Dogwood, Cornel) has S4, P4, A4, G2. Leaves opposite.

_Drupe_ with a bilocular, 2-seeded stone.--_Aucuba_, diœcious; unilocular ovary; 1 ovule; 1-seeded berry.--_Garrya._--_Helwingia._

80 species; N. Temp. The fruits of _Cornus mas_ are edible;
the wood is very hard; gum is found in some. Several species
of _Cornus_ and _Aucuba japonica_ (Japan) are cultivated as
ornamental shrubs.

Order 2. =Araliaceæ (Ivies).= Principally _trees_ or _shrubs_ with _solid stems_. The leaves are _scattered_, simple or compound, with a sheath more or less developed. The flowers are most frequently situated in umbels or capitula which are either borne singly or in racemes, or in paniculate inflorescences. The small, most frequently yellowish-green flowers are =5=-_merous_, in the calyx, corolla, and andrœcium; the gynœceum may be 5-merous or may have some other number (=2=-∞). The styles are most frequently several, free; the _raphe_ of the ovules is turned _inwards_ as in the Umbelliferous plants. The fruit is a _drupe_ or _berry_.--~Stellate hairs often occur. The petals generally have a broad base, and a thick apex which is slightly incurved, and a distinctly valvate æstivation.~

_Hedera helix_ (Ivy) climbs by adventitious roots. The leaves are palminerved and lobed on the sterile branches, but often ovate and not lobed on the flowering branches. ~The flowers are yellowish-green and open in the autumn; they are slightly protandrous, and are visited by flies and wasps. Berries black. Endosperm ruminate.--_Panax._ _Aralia_ (with _Dimorphanthus_).~

375 species, 51 genera; especially in the Tropics (E.
Asia).--The Ivy, several species of _Aralia_, _e.g._ _A.
japonica_ (_Fatsia_), _Gastonia palmata_, are cultivated as
ornamental plants. Paper is manufactured from the pith of
_Aralia papyrifera_ (China).

Order 3. =Umbelliferæ.= _The stem is herbaceous_ with _hollow internodes_; the leaves are _scattered_, and have a broad, amplexicaul base, a _large, most frequently inflated sheath_, and generally a pinnate (often very much dissected) blade. ~Entire leaves are found in _Hydrocotyle vulgaris_; _Bupleurum_.~

The flowers are ☿, regular, small, but collected in _compound umbels_, that is, in “simple umbels,” which again are borne in umbels (for exceptions see _Hydrocotyleæ_); the external flowers in the simple umbel have often subtending bracts, which surround the base as an _involucre_, and may be termed the _small involucre_; the internal ones have no bracts; when involucral leaves are present at the base of the compound umbel, they may be termed the _large involucre_.

The _flower_ has =5= sepals (the median, as usual, posterior), =5= petals, =5= stamens and =2= carpels (in the median line) (Fig. 528). The calyx is often scarcely indicated. The petals have a short claw are most frequently obcordate, or have an incurved apex (Fig. 528 _B_, _C_), being incurved in the bud; they are white, rarely yellow (Fennel and Parsnips), blue or red. The flowers are sometimes zygomorphic, especially those on the circumference of the umbel, and in that case it is the petal which is directed outside (anterior) which is the largest, and the two posterior are the smallest (_e.g. Heracleum_). The stamens are _incurved_ in the bud. The 2 _free styles_ unite at the base into the “stylar-foot” (_stylopod_), a swollen nectary (Fig. 528 _B_, _C_); the ovary is bilocular, the raphe of the ovules being directed inwards. _The fruit is a schizocarp_, _dividing into two mericarps_; the plane in which these separate coincides with that of the union of the carpels, and the two _nut-like mericarps_ are in most genera kept together for awhile at the top of a thin, bifid, or undivided stalk (_carpophore_) which is in direct continuation with the flower-stalk (Fig. 537). Each mericarp has most frequently 5 more or less strongly projecting ridges, the _primary ridges_ (Figs. 530, 532, 534, 535, etc.), of which 3 lie on the back of the mericarp, the _dorsal ridges_, and 2 on its edge near the plane of division, the _marginal ridges_; five of these (10 ridges in all in the entire fruit) are placed opposite the calyx-teeth and the others between them. In some genera there are in addition 4 _secondary ridges_ to each mericarp between the primary ones (Fig. 528 _E_: the secondary ridges bear the long bristles). Inside these secondary ridges, or inside the grooves between the primary ridges, when the secondary ridges are absent, _oil ducts_ (vittæ, schizogenous ducts) are found in the pericarp, most frequently one in each groove; two are also often found on the ventral side of each mericarp (Figs. 528 _E_, 530 _ol_, etc.). The seed is most frequently united with the pericarp. The _embryo_ is _small_ and lies high up in the large, most frequently horny endosperm (Fig. 528 _D_).--The endosperm _does not contain starch, but oil_, and presents three different forms, of important systematic value: (=a=) those which are quite flat on the ventral side (_i.e._ the side turned towards the plane of splitting) (Figs. 528 _E_, 530, 531, 534, etc.): the majority of the genera, ORTHOSPERMEÆ (_e.g._ _Carum_, _Pastinaca_); (=b=) those in which the endosperm on the ventral side is provided with a longitudinal groove, often deep: CAMPYLOSPERMEÆ (_e.g._ _Anthriscus_); the transverse section is nearly a crescent (Fig. 532); (=c=) those in which the endosperm is concave on the ventral side (hollow in both longitudinal and transverse sections): CŒLOSPERMEÆ (_e.g._ _Coriandrum_) (Fig. 538).

The genera are distinguished first of all by the endosperm and
forms of fruit, the ridges and oil-ducts; then by the form of
the umbel, the calyx and corolla, by the absence or presence of
an involucre, etc.

1. HYDROCOTYLEÆ, PENNY-WORT GROUP. _Capitula_ or _simple umbels_ (all the other groups have compound umbels). No oil-ducts. Orthospermous.--_Hydrocotyle_ (Penny-wort). The fruit is _considerably compressed_ laterally (Fig. 529). The calyx-teeth are small. The leaves are peltate.--_Didiscus._--_Sanicula_ (Sannicle). The umbels are small, capitate, generally collected in a raceme; calyx-teeth distinct. ♂-and ♀-flowers in the same umbel. The fruits are round, studded with hooked bristles. No carpophore.--_Astrantia_ has an umbel surrounded by a large, often coloured involucre, with this exception it is the same as the preceding, but the fruit is slightly compressed, with 5 equal ridges. _Hacquetia_ (_Dondia_).--_Eryngium_ (Sea Holly): leaves often thorny. The flowers _are all sessile_, the inflorescence is thus a capitulum; each flower is often subtended by a bract, which is thorny like the involucre, resembling the burrs of the Teasel. The sepals are large.--~_Lagœcia_: one of the loculi of the ovary is suppressed.~

=2.= AMMIEÆ, CARAWAY GROUP (Figs. 530–532). The fruit has only the 10 primary ridges; it is usually short, almost spherical or broadly ovate and distinctly _compressed_ laterally. Oil-canals are most frequently present. Orthospermous (except _Conium_).--_Cicuta_ (Cow-bane). Pointed calyx-teeth. Glabrous herbs with pinnate or bipinnate leaves. ~_C. virosa_ has a thick, vertical rhizome, divided by transverse septa into many compartments; the leaflets are narrow, lanceolate, and dentate; the large involucre is wanting.~--_Apium_ (Celery). No calyx-teeth. _A. graveolens_, a maritime plant, has neither large nor small involucre; the umbels are short-stalked or sessile.--_Carum_ (Caraway). Calyx-teeth small; the large involucre is wanting or is only few-leaved. _C. carvi_ (Caraway). _C. petroselinum_, (Parsley) (Fig. 530). _Falcaria_; _Ammi_; _Helosciadium_; _Bupleurum_ (Hare’s-ear) with simple leaves and yellow corolla; _Pimpinella_ (Fig. 531); _Sium_; _Ægopodium_ (_A. podagraria_, Gout-weed) has bi- or tri-ternate leaves, with ovate, dentate leaflets; the large involucre is wanting.--_Conium_ is campylospermous (Fig. 532); the short, broadly ovate fruit has distinctly projecting, often wavy crenulate ridges. _C. maculatum_ (Hemlock) has a round, smooth stem with purplish spots.

=3.= SCANDICEÆ. This group has a distinctly oblong or linear fruit which is _slightly compressed laterally_, and generally prolonged upwards into a “beak”; wings absent. _Campylospermous._ Otherwise as in the Ammieæ.--_Anthriscus_ (Beaked Parsley) has a lanceolate fruit, round on the dorsal side, without ridges, but with a ten-ridged beak.--_Scandix_ (Shepherd’s-needle).--_Chærophyllum_ (Chervil): fruit lanceolate or linear with low, blunt ridges; beak absent or very short. _C. temulum_ has a red-spotted, hairy stem.--_Myrrhis_ (Cicely) has a short beak and sharp, almost winged ridges. _M. odorata_ (Sweet Cicely) has very long fruits.

=4.= SESELINEÆ, FENNEL GROUP (Figs. 533, 534). The fruit is slightly elliptical or oblong, in transverse section circular or nearly so, without grooves in the dividing plane; only primary ridges are present. Orthospermous.--_Fœniculum_ (Fennel) has yellow petals; both involucres are wanting; the fruit is oblong. The ridges are thick, all equally developed, or the lateral ridges are slightly larger (Fig. 534).--_Æthusa_ (_A. cynapium_, Fool’s Parsley); the large involucre is wanting or is reduced to one leaf, the small involucre is composed of three linear leaves which hang downwards on the outer side of the umbels. The fruit is spherical-ovate, with thick, sharp, keeled ridges, the lateral ones of which are the broadest.--_Œnanthe_ (Dropwort); the fruit (Fig. 533) has usually an ovate, lanceolate form, with distinct, pointed sepals and long, erect styles; the ridges are very blunt, the marginal ones a trifle broader than the others.--_Seseli_, _Libanotis_, _Cnidium_, _Silex_, _Silaus_, _Meum_, etc.

=5.= PEUCEDANEÆ, PARSNIP GROUP (Figs. 535–537). The fruit is most frequently very strongly _compressed_ dorsally, with broad, mostly _winged_, lateral ridges. Only primary ridges. The dorsal ridges may project considerably, but are not winged. Orthospermous.

Transverse section of fruit.]

Transverse section of fruit.]

=a.= The winged lateral ridges stand _out from each other_, so that the fruit appears to be 4-winged (Fig. 535).--_Angelica_; _Archangelica_ (Fig. 535); _Levisticum_ (Lovage).

=b.= The winged lateral ridges lie _close together_, and form one wing on each side of the fruit (Fig. 536).--_Pastinaca_ (Parsnip). Corolla yellow. The dorsal ridges are very weak; the oil-ducts do not reach quite as far as the base of the fruit. Both large and small involucres are wanting; leaflets ovate. _Anethum_ (Dill) is a Parsnip with more distinct dorsal ridges and filamentous leaflets. _Peucedanum_ (Hog’s-fennel); _Ferula_ (with _Scorodosma_, Fig. 536, and _Narthex_); _Dorema_.--_Heracleum_ (Cow-parsnip); the flowers in the margin of the umbels are often very large, zygomorphic, and project like rays, _e.g._ in _H. sibiricum_. The fruit is very flat, with very small dorsal ridges; the oil-ducts are more or less club-like and _do not reach as far as_ the base of the fruit (Fig. 537). _Imperatoria_; _Tordylium_.

=6.= DAUCEÆ, CARROT GROUP (Fig. 528). The fruit has 18 ridges, _i.e._ each fruitlet has 5 primary and 4 secondary ridges, the latter being often more prominent and projecting further than the primary ones. The oil-ducts are situated under the secondary ridges (Fig. 528).

=a.= ORTHOSPERMOUS: _Daucus_ (Carrot). The secondary ridges project much further than the primary, and bear on their crests a series of hooked spines (Fig. 528 _D_, _E_); these are much longer than the small bristles on the primary ridges. ~The involucral leaves of _D. carota_ (Carrot) are numerous and deeply pinnate; the inflorescence contracts during the ripening of the fruit, and since the external umbels have longer stalks than the central ones, they arch over them, and the inflorescence becomes hollow. For the terminal flower, see below.~--_Cuminum_; _Laserpitium_; _Melanoselinum_.

=b.= CAMPYLOSPERMOUS: _Torilis_ (Hedge Parsley). The primary ridges are covered with bristles; the secondary ridges are not. very distinct on account of the spines, which entirely fill up the grooves. _Caucalis_ (Bur Parsley).

=c.= CŒLOSPERMOUS: _Coriandrum_ (Coriander) has a smooth, spherical fruit (Fig. 538) with a distinct, 5-dentate calyx, the two anterior (_i.e._ turned outward) teeth being generally longer than the others; the two fruitlets scarcely separate from each other naturally; all the ridges project only very slightly, the curved primary ones least, the secondary ridges most.

POLLINATION. The flowers are adapted for insect-pollination;
they secrete nectar at the base of the styles; individually
they are rather small and insignificant, but yet are rendered
conspicuous by being always crowded in many-flowered
inflorescences. _Protandry_ is common, sometimes to such
an extent that the stamens have already fallen off before
the styles begin to develop (Fig 539, 2). Insect visits are
more frequent and numerous as the inflorescences are more
conspicuous. The flowers as a rule are ☿, but ♂-flowers are
often found interspersed among the others (Fig. 539), and the
number of these becomes greater on the umbels developed at the
latest period. A terminal flower, which differs from the others
in form, and in _Daucus carota_ often in colour also (purple),
is sometimes found in the umbel. The nectar lies so exposed and
flat that the flowers are principally visited by insects with
short probosces, especially Diptera; bees are less frequent
visitors, and butterflies rare.--1400 species (175 genera);
especially from temperate climates in Europe, Asia, N. Am. About
68 species in this country.

USES. A few are cultivated as ornamental plants. They are,
however, useful in medicine,[38] and for culinary purposes
on account of the _essential oils_ and _gum-resins_ which
in many are formed in root, stem, and fruit. The FRUITS of
the following are used: _Carum carvi_ [+] (Caraway), _Carum
petroselinum_ (Parsley; also the leaves and root; its home
is the Eastern Mediterranean); _Fœniculum capillaceum_ [+]
(Fennel; S. Europe); _Pimpinella anisum_ [+] (Anise; E.
Mediterranean); _Coriandrum sativum_ [+] (Coriander; S. Eur.);
_Œnanthe phellandrium_ (Water Dropwort); _Cuminum cyminum_
(Point Caraway; Africa; cultivated in S. Europe); _Anethum
graveolens_ (Dill). The LEAVES of the following are used as
pot-herbs: _Anthriscus cerefolium_ (Chervil); _Myrrhis odorata_
(Sweet Cicely; Orient.); _Conium maculatum_ [+] (the green
portions; Hemlock). Besides Parsley, the ROOTS of the following
are used: Carrot, Parsnip, _Sium sisarum_ (Sugar-root; E. Asia);
_Chærophyllum bulbosum_ (Chervil-root); _Levisticum officinale_
(foliage-shoots; S. Europe); _Imperatoria ostruthium_;
_Apium graveolens_ (Celery, the root in conjunction with the
internodes); _Pimpinella saxifraga_ and _magna_ (Pimpinell);
_Archangelica_ (Angelica, the root of _A. norvegica_ was
formerly an article of food in Norway). _Poisonous alkaloids_
are found in a few, such as Fool’s Parsley (_Æthusa cynapium_),
Hemlock (_Conium maculatum_), Cow-bane (_Cicuta virosa_)
and species of _Œnanthe_.--_Gum-resin_ is extracted from
various species: “Galbanum” from _Ferula galbaniflua_ [+] and
_rubricalis_ [+] (Persia); Asafœtida from _Ferula scorodosma_
[+] and _F. narthex_ [+]; Ammoniac-gum from _Dorema ammoniacum_
[+], all from Central and S. W. Asia. “_Silphium_” was an
Umbelliferous plant which grew in ancient times in Cyrene, and
from which the Romans extracted a valued condiment.

Family 25. =Hysterophyta.=

This family (with the exception of Aristolochiaceæ) includes only parasitic plants. Partly on this ground, and partly because they all have _epigynous_ flowers, they are considered to belong to the youngest type (which is expressed in the name ὕστερος, the one that comes after). It is not certain to which of the preceding families they are most nearly allied. ~Again, it is a matter of doubt whether the Aristolochiaceæ are related to the others; they are by Engler united with Rafflesiaceæ into one family, _Aristolochiales_.~

Order 1. _Aristolochiaceæ._ The majority are perennial herbs or twining shrubs, whose stalked, simple, and generally more or less cordate or reniform leaves are borne in 2 rows and are exstipulate. The flowers are _hermaphrodite_, _epigynous_, regular or zygomorphic; perianth-leaves united, _simple_ but most frequently _petaloid_ and 3-merous; 6 or 12 (in _Thottea_ as many as 36) stamens with _extrorse_ anthers. The ovary is more or less completely 4–6-locular with ovules attached in the inner angles of the loculi (Fig. 540 _kf_). The style is short, and has a large, radiating stigma (Fig. 540 _n_). Fruit a capsule. Seeds rich in endosperm.

_Asarum europæum._ Each shoot has 2 reniform foliage-leaves, between which the terminal flower is borne (the rhizome becomes a sympodium by development of the bud in the axil of the upper foliage-leaf). The flower is _regular_ and has a bell-shaped perianth with 3 outer valvate, and 3 inner small segments (which may be wanting). =12= (2 × 6) free, extrorse stamens, 6 carpels.--_Aristolochia clematitis_ (Birth-wort) has an erect, unbranched stem, bearing many flowers in the leaf-axils, in a zig-zag row (accessory buds in a unipared scorpioid cyme). The flowers are zygomorphic (Fig. 540), formed by 3 alternating, 6-merous whorls. The perianth has a lower, much-distended part (_k_), succeeded by a narrow, bent tube (_r_), which passes over into an oblique, almost tongue-like projection (6 vascular bundles indicate that the number 6 is prevalent here, as in _Asarum_); =6= stamens (Fig. 540 _a_), with the dorsal portion turned upwards, are united with the short style to form a _stylar column_; they are placed quite beneath the 6 commissural stigmatic rays, which arch over them as short, thick lobes. ~Protogynous; POLLINATION is effected in _Arist. clematitis_ by small flies; these enter the erect unfertilised flower through the tube (Fig. 540 _A_, _l_) without being prevented by the stiff, downwardly-turned hairs which line the tube and prevent their escape; they find the stigma (_n_) fully developed, and may pollinate it with the pollen they have brought with them. The stigmas then straighten and wither (_B_, _n_), the anthers open, and the flies may again be covered with pollen; but the hairs which blocked up the tube do not wither until the anthers have shed their pollen, and only then allow the imprisoned flies to escape and effect cross-pollination. Prior to pollination, the flowers stand erect, but after this has taken place they become pendulous, and the perianth soon withers.--_A. sipho_ (Pipe-flower), another species, is a climber, and often grown in gardens; it has only one row of accessory buds in the leaf-axils.--200 species; chiefly in S. Am. OFFICINAL: the rhizome of _Aristolochia serpentaria_ (N. Am.).~

Order 2. =Santalaceæ.= Parasites containing chlorophyll, which, by the help of peculiar organs of suction (haustoria) on their roots, live principally on the roots of other plants. Some are herbs, others under-shrubs. The regular, most frequently ☿-flowers have a simple perianth, which is gamophyllous, 3- or 5 partite with the segments valvate in the bud, and a corresponding number of stamens opposite the perianth-leaves. In the inferior ovary there is a _free, centrally placed_, often long and curved _placenta_ with three ovules (one opposite each carpel); these are naked, or in any case have an extremely insignificant integument. Fruit a nut or drupe. Seed without testa. Endosperm fleshy. 225 species; chiefly in the Tropics.--_Thesium_, a native, is a herb with scattered, linear leaves and small 5-merous flowers (P5, A5, G3) in erect racemes; the subtending bracts are displaced on the flower-stalks. Fruit a nut.--_Osyris_ (diœcious shrub; 3-merous flowers) is another European genus.--_Santalum album_, which grows in E. Ind., yields the valuable, scented Sandalwood, the oil of which is used medicinally.--_Quinchamalium._

_Myzodendron_ is a reduced form of the Santalaceæ; the ♂-flowers
are without perianth; the perianth of the ♀-flower is 3-merous.
About 7 species; S. Am.; parasitic on a Beech (_Nothofagus_).
The fruit has 3 feathery brushes, alternating with the lobes
of the stigma, which serve as flying organs and to attach the
fruits to a branch (Fig. 541), the brushes twining round as
soon as they come in contact with it. There is only 1 seed in
the fruit, which germinates by a long, negatively heliotropic
hypocotyl, and is attached by a radicle modified into an
haustorium.

Order 3. =Loranthaceæ= (=Mistletoes=). Plants containing chlorophyll which are parasites on trees, and most frequently have opposite, simple, entire leaves and regular, epigynous, often unisexual, 2- or 3-merous flowers, with single or double perianth. Stamens equal in number and opposite to the perianth-leaves, free, or in varying degrees united to one another. The inferior ovary is constructed as in the Santalaceæ, the ovules being situated on a low, free, centrally-placed placenta, but the placenta and ovules unite with the wall of the ovary into _one connected, parenchymatous mass_, in which _the embryo-sacs are imbedded_. Only 1 (less frequently 2–3) of the 1–6 embryo-sacs is fertile. The number of the carpels however varies. The fruit is a _1-seeded berry_, whose inner layer is changed into a _tough slimy mass_ (bird-lime), which serves to attach the fruits to other plants.

The two groups, _Loranthoideæ_ and _Viscoideæ_, are
distinguished by the fact that the former has a distinct
“calyculus,” _i.e._ an entire or lobed, or dentate swelling
on the receptacle below the perianth. The majority of the
Loranthoideæ have a petaloid perianth; in all the Viscoideæ, on
the other hand, it is sepaloid.

The Mistletoe (_Viscum album_, Fig. 542) is a native, evergreen plant which may be found growing on almost any of our trees (sometimes on the Oak), and, like other Loranthaceæ, it produces swellings of the affected branches. ~Its spherical white berries (Fig. 542 _A_) enclose (1–) 2–3 green embryos; they are eaten by birds (especially Thrushes), and are partly sown with their excrement, partly struck or brushed off the branches of the trees, the seed being enclosed, at maturity, by viscin, _i.e._ “bird-lime.” The seeds may also germinate on the branches, without having first passed through the alimentary canal of the birds. On germination, the hypocotyl-axis first appears, as in Fig. 541, and bends towards the branch; the apex of the root then broadens, and forms at the end a disc-like haustorium, from the centre of which a root-like body grows through the bark into the wood, and ramifies between the bark and wood. Suckers are developed on the root like strands which are formed in this manner, without, however, having a rootcap; they are green, and penetrate the wood by the medullary rays (Fig. 542 _C_). Adventitious buds may also be developed from the root-like strands which break through the bark and emerge as young plants. The young stem quickly ceases its longitudinal growth, and lateral shoots are developed from the axils of its foliage-leaves. These and all following shoots have a similar structure; each of them bears a pair of scale-leaves (Fig. 542 _A_, _a_) and a pair of foliage-leaves (Fig. 542 _A_, _b_), and then terminates its growth, if it does not produce an inflorescence; new lateral shoots proceed from the axils of the foliage-leaves, and the branching, in consequence, is extremely regular and falsely dichotomous. Only one internode (shoot-generation) is formed each year, so that each fork indicates one year. The foliage-leaves fall off in the second year. The inflorescence is a 3(-5)-flowered dichasium (Fig. 542 _A_, _m_ is the central flower, _n_ the lateral). The plants are _diœcious_; the ♂-flower as a rule is 2-merous: perianth 2 + 2, each leaf of which bears on its inner side 6–20 pollen-sacs, each of which opens by a pore; this relationship may be considered to have arisen from the union of the perianth-leaves with the multilocular stamens (2 + 2) placed opposite them. The ♀-flowers always have Pr 2 + 2, G2.--_Loranthus_ is also found in Europe (it has a 3-merous flower), especially in the central and south-eastern districts, on _Quercus cerris_ and _Q. pubescens_; but the great majority of the 520 species grow in the Tropics on trees which they ornament with their often brightly-coloured flowers, and ultimately kill when present in too great numbers. The pollination in the numerous Loranthaceæ with unisexual flowers, is effected by the wind. In _Viscum album_ this takes place in autumn, the actual fertilisation in the following spring, and the maturity in November or December; in the succeeding month of May the berry is ready to germinate, and falls off.~

USES. Birdlime from _Viscum album_.

Order 4. =Rafflesiaceæ= and Order 5. =Balanophoraceæ=.
These orders comprise _root-parasites_, almost entirely
devoid of chlorophyll; they are reddish or yellow, without
foliage-leaves (Fig. 543). As far as our knowledge of these
rare tropical plants extends, they have thalloid organs of
vegetation resembling the root-like strands of _Viscum_, or
they are filamentous and branched like Fungus-hyphæ; they live
in and on the tissues of the host-plant, from which their
flowering-shoots, often of mushroom-like form, are subsequently
developed (Fig. 543). In order to unfold they must often break
through the tissues of the host-plant.

Of the RAFFLESIACEÆ, _Cytinus hypocistus_ is found in S. Europe
living on roots of _Cistus_-plants and to some extent resembling
_Monotropa_ (Fig. 543). _Rafflesia_ is the best known; it lives
on roots of _Cissus_-species (belonging to the Ampelidaceæ) in
Java; its yellowish-red, stinking flowers attain a gigantic
size (one metre or more in diameter), and are borne almost
directly on the roots of the host-plant. Besides these there
are other genera: _Brugmansia_, _Pilostyles_, _Hydnora_.--To
BALANOPHORACEÆ (Fig. 543) belong: _Balanophora_, _Langsdorffia_,
_Scybalium_, _Sarcophyte_, _Helosis_, etc., and in S. Europe,
_Cynomorium coccineum_.

Sub-Class 2. =Sympetalæ.=

The characters which separate this from the first Sub-class, the Choripetalæ, have been described on page 336. They consist in the following: the flower is always verticillate, generally with =5= sepals, =5= petals, =5= stamens, and =2= carpels (in the median plane), the calyx is generally persistent and gamosepalous, the corolla is gamopetalous and united to the stamens, which are therefore adnate to it, the ovules have only _one_ thick integument and a small nucellus. (The exceptions are noted later.)

This Sub-class is no doubt more recent than the Choripetalæ; it
is also peculiar in including fewer trees and shrubby forms than
the latter.

The Sympetalæ may be separated into 2 sections:--