Chapter II: ACROGYNÆ. The apex of the stem or of certain branches is adapted (8)

Order 2. =Fumariacæ= (=Fumitories=). This order differs from the closely allied Papaveraceæ in the absence of latex, a poorer flower, generally _transversely zygomorphic_ (Fig. 393 _B_), in which case one or both of the outer lateral petals are gibbous, or prolonged into a spur; the stamens are especially anomalous. Sepals =2=, caducous; petals 2 + 2; stamens 2, _tripartite_; each lateral anther is _bilocular_ (Figs. 393 _A_, _B_; 395); gynœceum bicarpellate. The fruit is a nut or siliqua-like capsule. _Endosperm._--_Herbs_ with scattered, repeatedly pinnately-divided leaves without stipules, generally quite glabrous and glaucous; the flowers are arranged in racemes with subtending bracts, but the bracteoles are sometimes suppressed.

_Dicentra_ (syn. _Dielytra_) and _Adlumia_ have a doubly symmetrical flower, with a spur or gibbous swelling at the base of _each_ of the laterally-placed petals (Figs. 393 _A_, 394). _Corydalis_ has a zygomorphic flower, _only one of_ the lateral petals _having a spur_, and consequently there is only one nectary at the base of the bundle of stamens, which stands right in front of the spur (Fig. 393 _B_, 395, 396). The fruit is a many-seeded siliqua-like capsule. ~A peculiarity of the flower is that the plane of symmetry passes _transversely_ through the flowers, whilst in nearly all other zygomorphic flowers it lies in the median line. Moreover, the flower is turned, so that the plane of symmetry ultimately becomes nearly vertical, and the spur is directed backwards.--Many species have subterranean tubers; in these the embryo germinates with _one cotyledon_, which is lanceolate and resembles a foliage-leaf. The tuber is in some the swollen hypocotyl (_C. cava_), in others a swollen root (_C. fabacea_, etc.), which grows down through the precisely similar swollen root of the mother-plant. The sub-genus _Ceratocapnos_ has dimorphic fruits (nuts and capsules) in the same raceme.~ _Fumaria_ differs from _Corydalis_ only by its almost drupaceous, one-seeded nut (Fig. 395).

THE STRUCTURE OF THE FLOWER. _Hypecoum_ among the Papaveraceæ
is the connecting link with the Fumariaceæ. The diagram (Fig.
393 _C_) corresponds both in number and in the relative position
of its members with that of most of the other Papaveraceæ (Fig.
391), except that there are only four stamens (with extrorse
anthers). In _Dicentra_ (Fig. 393 _A_), the two central
(uppermost) stamens are absent, but each of the two lateral ones
are divided into three filaments, of which the central one bears
a four-locular anther, and each of the others a two-locular
(half) anther. _Corydalis_ and _Fumaria_ stand alone in the
symmetry of the flower, differing from _Dicentra_ in having only
one of the lateral petals (Fig. 393 _B_, _sp_) prolonged into
a spur, while in _Dicentra_ both the petals are spurred. This
structure has been interpreted in various ways. According to Asa
Gray the median stamens are absent in the last-named genera, and
the lateral ones are split in a similar manner to the petals of
_Hypecoum_. Another, and no doubt the most reasonable theory
(adduced by De Candolle), is: that two median stamens are split,
the two parts move laterally, each to their respective sides
and become united with the two lateral stamens; this affords a
natural explanation of the two half-anthers, and establishes a
close relationship to the Cruciferæ. A third interpretation,
held by Eichler and others, is as follows: the median stamens
are _always_ wanting; when they appear to be present, as in
_Hypecoum_, it is due to the fact that the side portions of
the lateral stamens _approach each other_ (as interpetiolar
stipules) and coalesce into an apparently single stamen.

130 species; mostly from the northern temperatures.

POLLINATION. _Fumaria_, with its inconspicuous flowers, has to
a great extent to resort to self-pollination. _Corydalis_, on
the other hand, is dependent on cross-pollination; _C. cava_
is even absolutely sterile with its own pollen. _Corydalis_
is pollinated by insects with long probosces (humble-bees,
bees), which are able to reach the honey secreted in the spur;
as they alight on the flowers they press the exterior petals
on one side (Fig. 396 _e_), so that the stigma, surrounded by
the anthers, projects forward; the proboscis is introduced in
the direction of the arrow in the figure, and during this act
the under-surface of the insect is covered with pollen, which
is transferred by similar movements to the stigma of another
(older) flower.--Ornamental plants; _Dicentra_ (_spectabilis_
and _eximia_), _Adlumia_, _Corydalis_.

Order 3. =Cruciferæ (Crucifers).= The flowers are _regular_, ☿; sepals 4, free (2 + 2), deciduous; petals 4, free, deciduous, unguiculate, placed _diagonally_ in one whorl, and alternating with the sepals; stamens 6; the 2 _outer_ are _short_, the 4 _inner_ (in reality the two median split to the base) _longer_, placed in pairs (tetradynamia of Linnæus); gynœceum syncarpous formed by 2 (as in the previous order, lateral) carpels, with 2 parietal placentæ, but divided into two loculi by a _spurious_ membranous dissepiment (_replum_) (Fig. 397). Style single, with a capitate, usually two-lobed stigma, generally commisural, that is, placed above the parietal placentæ (Fig. 397), but it may also be placed above the dorsal suture, or remain undivided. Ovules _curved_. The fruit is generally a bivalvular _siliqua_ (Fig. 398 _B_, _C_), the valves separating from below upwards, and leaving the placentæ attached to the replum; other forms of fruits are described below. The oily seeds _have no endosperm_ (endosperm is present in the two previous orders); the _embryo is curved_ (Figs. 398 _E_, _F_; 399, 400).--In general they are _herbaceous_ plants, without latex, with scattered, penninerved leaves, without stipules; the inflorescence is very characteristic, namely, a raceme with the flowers aggregated together at the time of flowering into a corymb, and _destitute of both bracts and bracteoles_.

Many are biennial, forming in the first year a close
leaf-rosette. By cultivation the tap-root can readily be induced
to swell out into the form of a tuber (Turnips, Swedes, etc.).
_Stipules_ are found indicated by small glands on the very
young leaves; in _Cochlearia armoracia_ they are fairly large
triangular scales. _Stellate hairs_ often occur. _Floral-leaves_
are occasionally developed. Terminal flowers are never found in
the inflorescences. _Iberis_ and _Teesdalia_ have _zygomorphic_
flowers. _Subularia_ (Fig. 403) is perigynous. The 2 external
sepals (Fig. 397) stand in the median plane; it may therefore
be supposed that there are two bracteoles outside these which,
however, are suppressed, and can only in a few instances be
traced in the young flower; the two lateral sepals are often
gibbous at the base, and serve as reservoirs for the nectar
secreted by the glands placed above them; they correspond in
position to the external petals of the Fumariaceæ. The 4 petals
which follow next arise simultaneously, and alternate with the
4 sepals; if it could be shown that these are merely 2 median
petals, which have been deeply cleft and the two parts separated
from each other and displaced to the diagonal position, there
would be a perfect correspondence with the Fumariaceous flower;
then the petals would be followed in regular alternation by the
2 lateral small stamens, the 2 median long stamens, which it
has been proved are split into 4 and placed in couples, and the
2 laterally-placed carpels,--in all 6 dimerous whorls. But the
formation of the corolla by the splitting of 2 petals does not
agree with the development of the flower or bear comparison, and
hence the only fact in favour of this theory is the otherwise
prevailing correspondence with the Fumariaceæ. Yet it may
be observed that in special cases each pair of long stamens
clearly enough arises from one protuberance and even later
on may be considerably united or entirely undivided (_e.g._
_Vella_); in other instances they are quite distinct from the
beginning, and it is possible that this latter condition has
become constant in the corolla. _Lepidium ruderale_ and others
have no corolla. _Senebiera didyma_ has only 2 median stamens.
_Megacarpæa_ has several stamens, no doubt by dédoublement, as
in Capparidaceæ.--The _number of carpels_ may also be abnormally
increased; _Tetrapoma barbareifolium_ has normally 4 carpels
with an equal number of placentæ and repla. It is supposed to
be a variety of _Nasturtium palustre_.--The 2–4–8–10 greenish
_glands_, which are found at the base of the stamens, are
nectaries, morphologically emergences, and not rudimentary
stamens. The forms of _fruits_ are of great systematic
significance, see the genera. In some species dimorphic fruits
are present, _e.g. Cardamine chenopodiifolia_ which has both
ordinary _Cardamine_-siliquas and 1-seeded siliculas.

The _curved embryo_ appears in five forms, which have
systematic importance: 1. To the PLEURORHIZÆ belong those
genera whose radicle (with the hypocotyl) lies bent upwards
along the _edge_ of the _flat_ cotyledons (Fig. 399); to
this group belong _Cardamine_, _Nasturtium_, _Cheiranthus_,
_Matthiola_, _Cochlearia_, _Draba_, _Iberis_, _Thlaspi_, etc.;
diagrammatic transverse section: ◯=.--2. To NOTORHIZÆ belong
those whose radicle lies in an upward direction along the
_back_ of one of the _flat_ cotyledons (Figs. 400, 413); _e.g._
_Hesperis_, _Sisymbrium_, _Lepidium_, _Capsella_, _Camelina_:
◯‖.--3. ORTHOPLOCEÆ differ from the Notorhizeæ in having the
cotyledons folded (not flat) (Fig. 398 _E_, _F_); to this belong
_Brassica_, _Sinapis_, _Raphanus_, _Crambe_, etc.: ◯>>.--4.
SPIROLOBEÆ: the radicle lies as in the Notorhizæ, but the
cotyledons are so rolled together that a transverse section of
the seed cuts them twice; _Bunias_: ◯‖‖.--5. DIPLECOLOBEÆ: the
cotyledons are folded forward and backward so that a transverse
section cuts them several times; _Subularia_, _Senebiera_: ◯‖‖‖.

On _germination_ the cotyledons appear above the ground as green leaves; in the Orthoploceæ they are bilobed, in the _Lepidium_-species divided.

1. =Silicula, broad replum= (Siliculosæ latiseptæ), valves flat or slightly vaulted, and the replum extends through the greatest width of the silicula (Fig. 404). The seeds are situated in two rows.

◯=: _Cochlearia_ (Horse-radish): the siliqua is nearly spheroid; glabrous herbs, generally with fleshy, stalked leaves, and white flowers.--_Draba_ has an oblong, lanceolate, somewhat compressed silicula; herbs with small rosettes of leaves, most frequently with stellate and long-stalked racemes.--_Alyssum_ and _Berteroa_ are whitish, on account of the stellate hairs; they have a more compressed and round or elliptical silicula. _Vesicaria_; _Aubrietia_. _Lunaria_ (Honesty, Fig. 401): very broad and flat silicula with long stalk (the receptacle as in Capparidaceæ).

◯‖: _Camelina_ (Gold-of-pleasure) has a spheroid, pear-shaped siliqua with a small rim passing right round (Fig. 402). _Subularia_ (Awlwort), an aquatic plant with _perigynous_ flower (Fig. 403) and folded cotyledons.

2. =Silicula, narrow replum= (Siliculosæ angustiseptæ), _i.e._ the replum is much shorter than the arched, more or less boat-shaped valves (Figs. 405, 406, 407).

◯=: _Thlaspi_ (Penny-Cress) has a flat, almost circular silicula, emarginate or cordate, with a well-developed wing round the edge (Fig. 406). _Iberis_ and _Teesdalia_: the racemes during flowering are especially corymbose, and the most external petals of the outer flowers project radially and are much larger than the other two (the flower is _zygomorphic_).--_Biscutella_, _Megacarpæa_.

◯‖: _Capsella_ (Shepherd’s-Purse) has a wingless, obcordate or triangular silicula (Fig. 407). _Lepidium_ (Pepperwort) has a few–(2–4) seeded, slightly winged, oval silicula. _Senebiera_ has a silicula splitting longitudinally into two nut-like portions; its cotyledons are folded.--~_Anastatica hierochuntica_ (“Rose of Jericho”) is an annual, silicula-fruited, desert plant (Arabia, Syria, N. Africa). After the flowering all its then leafless branches bend together upwards, forming a kind of ball; this spreads out again on coming in contact with water, and the fruits then disseminate their seeds, which germinate very quickly, often in the fruit.~

3. =Siliqua= (Siliquosæ). The fruit is a true siliqua, several times longer than broad. The seeds in most are borne apparently in one row.

◯>>: _Brassica_ (Cabbage). The seeds are placed apparently in one row in each loculus (Fig. 398 _C_); the style is long and round; the valves have only 1 strong, longitudinal rib.--_Melanosinapis_ (_M. nigra_, Black-mustard); the style is compressed, two-edged; the valves of the siliqua are one ribbed.--_Sinapis_ (Mustard); quadrangular or flat style (in which in most cases there is a seed) and 3–5 strong, longitudinal ribs on the valves.--_Eruca_ differs from _Brassica_ by the shorter siliqua, broad, sword-like “beak” and seeds in two rows.

◯= (Fig. 399): _Cardamine_ (Bitter Cress) has a long, linear siliqua, with flat, unribbed, _elastic_ valves. The leaves are most frequently pinnatifid or pinnate. ~_C. pratensis_ reproduces by buds formed in the axils of the leaves.~--_Arabis_ (Rock Cress); _Matthiola_ (Stock); _Cheiranthus cheiri_ (Wallflower); _Barbarea_ (Winter Cress) (double-edged, quadrangular siliqua); _Nasturtium_ (_N. officinale_, Water-cress); the siliqua of the latter genus is in some species short, in others long.

◯‖ (Fig.400): _Sisymbrium_ (Hedge Mustard) the valves of the siliqua are 3-ribbed.--_Erysimum_; _Hesperis_; _Schizopetalum_ (with fimbriate petals).

4. =Fruit jointed= (Lomentaceæ). The fruit is divided by transverse walls into as many spaces as there are seeds, and dehisces at maturity, generally _transversely_, into a corresponding number of nut-like joints (“articulate-siliqua.”)

◯=: _Crambe_ (Kale, Fig. 408). The fruit has only 2 joints. The lower one resembles a short, thick stalk, and is barren, the upper one is spherical, and has 1 seed.--_Cakile_ (_C. maritima_, Sea-kale); the lower node is triangular, 1-locular, the upper one more ensiform, 1-locular (Fig. 409).

◯>>: _Raphanus_ has a long siliqua, which, in the garden Radish (_R. sativus_), is spongy and slightly abstricted (Fig. 411), but neither opens nor divides transversely (a kind of dry berry), and which in the Wild Radish (_R. raphanistrum_) (Fig. 410) is abstricted in the form of a string of pearls, and separates into many joints. ~_R. sativus_; the “Radish” is formed by the hypocotyl, after the bursting of its external, cortical portions (of which there are generally two patches at the top of the Radish).~

5. =Siliqua indehiscent= (Nucumentaceæ). The fruit is a short, _unjointed_, unilocular and 1-seeded nut, and the fruit-stalks are often long, slender, and drooping. (Sometimes a thin endosperm is present).--_Isatis_ (Woad) has most frequently an oblong, small-winged nut; ◯‖ (Figs. 412, 413).--_Bunias_; _Neslia_.

[The systematic division of this order given above is founded
upon that of A. P. de Candolle. Prantl (_Engler and Prantl, Nat.
Fam._), 1891, adopts a somewhat different system, which may
briefly be summarised as follows:--

_A._ Hairs unbranched or absent; no glandular hairs.

1. THELYPODIEÆ. Stigma equally developed on all sides; style
undivided or prolonged above the middle of the carpels,
or turned back.--_Stanleyinæ_; _Heliophilinæ_.

2. SINAPEÆ. Stigma strongly developed above the placenta;
style beaked or two-lobed.

_a._ Cotyledons arising behind the bend of the
embryo.--_Lepidiinæ._

_b._ Cotyledons arising at the bend of the embryo.

α. Only lateral nectaries. Generally a silicula or
indehiscent fruit.--_Cochleariinæ._

β. Generally a siliqua, more rarely a silicula or
transversely-divided or indehiscent fruit.
Nectaries generally lateral and
median.--_Alliariinæ_; _Sisymbriinæ_; _Vellinæ_;
_Brassicinæ_; _Cardamininæ_.

_B._ Hairs collectively or partially branched, very rarely
entirely absent; glandular hairs are sometimes also present.

1. SCHIZOPETALEÆ.

2. HESPERIDEÆ. Stigma strongly developed above the placenta;
style undivided or prolonged above the placentæ into
shorter or longer lobes.

_a._ Surface cells of the replum, not divided
diagonally.--_Capsellinæ_; _Turritinæ_;
_Erysiminæ_; _Alyssinæ_.

_b._ Surface cells of the replum divided
diagonally.--_Malcolmiinæ_; _Hesperidinæ_;
_Moricandiinæ_.]

POLLINATION. Honey is secreted by the nectaries mentioned
above; but the position of the stamens is not always the most
favourable for pollination by insects (in these flowers the
honey-seeking insect must touch the anthers with one of its
sides and the stigma with the other), and self-fertilisation
is common. In some species (_Cardamine pratensis_) the long
stamens turn their anthers outwards towards the small stamens,
so that 3 anthers surround each of the two large entrances to
the nectaries.

1200 species (180 genera), especially in the cold and
temperate parts of the Old World (Europe, W. Asia). Many
are _weeds_ in this country, _e.g._ Wild Cabbage (_Brassica
campestris_), Charlock (_Sinapis arvensis_), Wild Radish
(_Raphanus raphanistrum_) and others.--The order is acrid and
oleaginous. Oil is obtained from many of the oil-containing
seeds, especially of the Rape (_Brassica napus_), Summer-Rape
(the oil-yielding cultivated form of the Field-Cabbage) and
_Camelina_. Several are pot-herbs or fodder plants, _e.g._
Cabbage

(_Brassica oleracea_) with its numerous varieties: Cauliflower
(var. _botrytis_; the entire inflorescence is abnormally
branched and fleshy), Kohlrabi (var. _gongylodes_, with
swollen, tuberous stem), Kale, Red-Cabbage, White-Cabbage,
etc.; _B. campestris_, var. _rapifera_ (Turnip); _B. napus_,
var. _rapifera_ (Swede); _Raphanus sativus_ (Radish from W.
Asia), _R. caudatus_ (long Radish); _Nasturtium officinale_
(Water Cress), _Lepidium sativum_ (Garden Cress), and _Barbarea
præcox_ (Early Cress); _Crambe maritima_ (Sea-Kkale). The
seeds of the following are especially used as spices: (the
flour of) _Melanosinapis_ (Black-mustard), and _Sinapis
alba_ (White-mustard), which are _officinal_ like the root
of _Cochlearia armoracia_ (Horse-radish, E. Eur.). The
herbaceous parts of _Cochlearia officinalis_ and _danica_
are medicinal.--A blue dye (woad) is extracted from
_Isatis_.--Ornamental plants: _Cheiranthus cheiri_ (Wallflower),
_Matthiola_ (Stock), _Iberis_, _Hesperis_, _Lunaria_, and others
(especially from S. Eur.). Sweet-scented flowers are rare.

Order 4. =Capparidaceæ= (=Capers=). The relationship with the
Cruciferæ is so close that certain forms are with difficulty
distinguished from them. The diagram of the flower is the same
in the number and position of its parts, but it differs in the
modifications which occur in the development of the stamens. In
some genera all 4 stamens are undivided; in others both the 2
median ones are divided as in the Cruciferæ (6 stamens, but _not
tetradynamous_) (Fig. 414); in other genera only 1 of these; in
other instances again they are divided into more than 2; and
finally the 2 lateral ones also may be found divided, so that
_indefinite stamens_ occur (Fig. 415). The bicarpellate gynœceum
is _unilocular_ (without replum), but more than 2 carpels may
occur. The ovary is elevated on a _stalk_ (sometimes as much
as 1 foot in length); also between the stamens and corolla a
similar stalk may be found (Fig. 414). The fruit is long and
siliquose (_Cleome_, _Polanisia_, _Gynandropsis_), or a berry
(_Capparis_). Endosperm absent. Some have zygomorphic flowers.
Gamosepalous calyx and perigynous flowers also occur.--350
species; especially in the Tropics. The majority are trees
and shrubs, and they differ also from the Cruciferæ in having
distinct stipules present in some species.

“Capers” are the flower buds of the climbing, thorny shrub,
_Capparis spinosa_ (Fig. 415), which grows in the Mediterranean.

Family 11. =Cistifloræ.=

The flowers in this family are perfect, regular (except _Resedaceæ, Violaceæ_), hypogynous, the perianth-leaves free (a few have them slightly united), æstivation most frequently imbricate; they are eucyclic in the andrœcium, and most frequently in the other parts, and generally 5-merous with S5, P5, A5 + 5, G3, but other numbers also occur; several have _indefinite stamens_, but the stamens arise (where the development is known) in _centrifugal order_ and are arranged, often very distinctly, _in bundles_; in other words, the large number of stamens is formed by the splitting of a small number (most frequently 5); a true spiral arrangement is never found. Gynœceum syncarpous, multicarpellary (_Dilleniaceæ_ and a few _Resedaceæ_ are apocarpous), most frequently the number of carpels is 3, forming a _unilocular ovary_ with _parietal placentæ_, but parallel with this, multilocular ovaries, with the ovules placed in the inner angle of the loculi, are also found, and a few genera have a free, centrally-placed placenta. The fruit is most frequently a capsule. The dehiscence is never with a “replum,” _i.e._ the persistent frame of the placenta, as in the family Rhœadinæ. One half of the orders has endosperm (_Violaceæ_, _Cistaceæ_, _Droseraceæ_, _Bixaceæ_, _Ternstrœmiaceæ_, etc.), the other has no endosperm (_Resedaceæ_, _Hypericaceæ_, _Elatinaceæ_, _Tamaricaceæ_, etc.); some have a curved, the majority a straight embryo. ~The family is scarcely quite natural; in the future the orders will probably be arranged differently.~

Order 1. =Resedaceæ (Mignonettes).=--Herbs or small shrubs with spirally-placed leaves and very small, gland-like stipules (as in Cruciferæ); the ☿, hypogynous flowers are _zygomorphic_, and arranged in racemes or spikes typically without bracteoles. The zygomorphic structure is produced by the _greater development of the posterior side of the flower_, especially the petals and the nectary (“disc,” in Fig. 416 _d_) which is situated between the petals and stamens; in general there are 5–8 free sepals and petals, the latter consisting of a large scale-like _sheath_ with a fimbriated blade (see Fig. 416); stamens numerous; carpels 6–2 united together; ovary unilocular with parietal placentæ, but _the cavity of the ovary is not closed_ at the top. In _Astrocarpus_ the gynœceum is apocarpous. The fruit is most frequently a capsule; the seeds are reniform, without endosperm, and the embryo is _curved_.

This order connects the Rhœadinæ with the Cistifloræ. It is
closely allied to the Rhœadinæ by its external appearance, even
by the smell and taste, the parietal placentation, structure of
the seeds, the inflorescences, etc., whilst by the irregular
flowers and the disc placed at the posterior side of the
flower, _it is allied to Capparidaceæ_, but differs from this
order in not having its characteristic number (2–4) and by
the very different mode of dehiscence of the fruit, etc. It
differs from the other orders of this family chiefly in the
fact that the number of the perianth-leaves is not constantly
5. In _Reseda luteola_ both the calyx and corolla appear to
be 4-leaved, because the posterior sepal is suppressed, and
the 2 posterior petals are united. Where there are 10 stamens,
they stand in 2 whorls, _i.e._ in front of the sepals and
petals; if there are several, their position depends upon the
splitting.--_Astrocarpus_ is remarkable for its apocarpous fruit
and the position of the ovules on the _dorsal_ suture of the
carpel.

The yellow, flat disc at the back of the flower serves as a
nectary, the honey being protected by the lobes of the petals.
If pollination by insects is not effected, then self-pollination
may take place, at all events in _R. odorata_.

45 species; the majority in the Mediterranean and in Persia.
_Reseda odorata_ (from Egypt) is cultivated on account of its
sweet scent; _R. luteola_ (“Dyer’s Weed”) yields a yellow dye.

Order 2. =Droseraceæ (Sundews).= Herbs, chiefly living on moors or in water, and whose leaves are adapted to catch and digest small animals. With regard to the flower, they are closely allied to the Violaceæ, especially to those with regular flowers. _Drosera_ (Sundew) has a long-stalked scorpioid cyme with regular, ☿, hypogynous flowers, 5-merous as in _Viola_. S5, P5, A5, G3 (in a syncarpous gynœceum, with free, bifid styles and basal or parietally-placed ovules in the unilocular ovaries). The capsule opens also as in _Viola_, but, among other differences, the styles are free, the seeds very small, and surrounded by a loosely lying, thin shell. ~_Drosera_ has radical, long-stalked leaves with the blade (Fig. 417) covered by numerous strong glandular hairs, placed on the edge and in the middle; when small animals are caught by these hairs, the latter and the entire blade close slowly over them dissolving and absorbing all the digestible matter as nourishment.~

_Dionæa muscipula_ (Fly-trap; N. Am.) has the same appearance
as _Drosera_, but the leaves are constructed as in Fig. 418.
The stalk is flat and winged, the blade small, circular, with
powerful, pointed teeth along the edge, and on its surface are 6
small bristles (_A_), which are very sensitive. When these are
touched the blade quickly closes, folding along the midrib (_B_,
_C_) and imprisoning the irritating object, the teeth round the
edges fitting like the teeth of a trap. If it happens to be an
insect or similar body, a digestive fluid is secreted which,
like the gastric juice, dissolves the digestible portions.
_Aldrovandia vesiculosa_ (Central and S. Europe) captures small
aquatic animals in a similar manner; it is a floating, aquatic
plant, the two halves of its leaves also close together when
irritated (Fig. 419).--_Drosophyllum._

About 110 species; most of them in the temperate regions.

Orders 3 and 4. =Sarraceniaceæ and Nepenthaceæ.= These two
orders are perhaps most closely allied to the Droseraceæ and
agree with these, among other things, in the manner of taking
nourishment. Like the Droseraceæ they absorb nitrogenous food
from dissolved animal matter by means of their leaves, which are
specially constructed both to catch, to retain, and to digest
any small animals which may be caught. The SARRACENIACEÆ are
North American marsh-plants (10 species) which have pitcher-like
leaf-stalks, in the cavity of which a fluid (with properties
approaching those of gastric juice) is secreted, and which bear
at the apex a small, lid-like blade; these leaf-stalks are the
catching and digestive organs.--_Sarracenia, Darlingtonia._

NEPENTHACEÆ has only 1 genus, _Nepenthes_ (the Pitcher-plant;
about 35 species), especially found in tropical E. Asia; the
majority are climbing shrubs. The leaf-stalks are twining
organs, and terminate either simply in a tendril, or in addition
to this, with a pitcher-shaped body (which in some species may
be as much as a foot in length) on whose upper edge a lid-like
structure is found (Fig. 420). In this pitcher, as among the
Sarraceniaceæ, a fluid is secreted which is able to digest the
animals captured (sometimes rather large) and which corresponds
in some degree to the gastric juice.

Order 5. =Violaceæ (Violets).= The flowers are ☿, and generally zygomorphic, hypogynous, with S5, P5, A5, G3 (Fig. 421). The stamens are closely applied to the ovary, they have a very short filament, and at their summit generally a membranous appendage formed by the prolongation of the connective (Fig. 422 _g_). The ovary is unilocular with 3 parietal placentæ; style undivided (Fig. 422 _B_). The fruit is usually a 3-valved capsule, opening along the dorsal sutures (Fig. 423). Embryo straight; endosperm fleshy (Fig. 425).--Many are herbaceous plants (_e.g. Viola_), but in the Tropics shrubs are also found (_e.g. Ionidium_); a few are lianes; the leaves are scattered, with stipules, and involute in the bud.

_Viola._ The sepals are prolonged backwards beyond the point of insertion (appendiculate); the corolla is polypetalous, descending imbricate, and zygomorphic, its anterior petal being larger than the others and provided with a spur (Fig. 421). The 2 anterior of the 5 almost sessile stamens are provided with a spur-like nectary, which protrudes a considerable distance into the petaloid spur (Figs. 421, 422 _n_, _sp_). The style is club-like, and bears the stigma in a groove on the anterior side (Fig. 422 _st_). ~Herbs with rhizomes, or annuals; flowers solitary. _V. odorata_, _canina_, etc., have cleistogamic flowers which produce fruit in addition to the large, coloured (violet) flowers. The Pansy (_V. tricolor_) has large flowers adapted for insect-pollination, and also smaller, less conspicuous ones designed for self-pollination. The stigma, as in Fig. 422 _A_, _st_, and _B_, is situated on the anterior side of the stylar-head, immediately in front of the channel leading down to the spur (_sp_); below it is situated a valve, easily covered with pollen when the proboscis of an insect is introduced into the spur, but which closes upon its withdrawal; cross-pollination is thus secured.--The sweet-scented _V. odorata_ is visited by the honey-bee, which insures cross-pollination, and in the absence of insect visits it effects self-fertilisation by cleistogamic flowers. The conspicuous but scentless _V. tricolor_, var. _vulgaris_, is less frequently visited by insects (humble-bees). In _V. silvatica_ and _V. canina_ the pollen is carried on the head or proboscis of the honey-sucking bee.--The fruits of _V. odorata_ bury themselves slightly in the soil. In the others the fruits are raised above the ground; the 3 boat-shaped valves close together along the central line, and eject the seeds, one by one, with much violence, so that they are thrown to a great distance.~

FIG. 423.--Capsule after dehiscence (nat. size).

FIG. 424.--External view of the seed.

FIG. 425.--Seed in longitudinal section.]

The _Alsodeia_-group has regular or almost regular flowers.
Gamopetalous corollas are found in _Paypayroleæ_. _Sauvagesieæ_
differs the most by its regular corolla, and 5–∞ free or united
staminodes.

250 species; especially in the Tropics.--The _Ionidium_-species
are used as ipecacuanha. A number of _Viola_-species are
cultivated as garden plants, especially _V. odorata_
(sweet-scented Violet) and _V. tricolor_, which have a large
number of varieties.

Order 6. =Frankeniaceæ.= A small order with doubtful
relationships. Perennial herbs or shrubs; beach plants with
nodose stem. Sepals united, petals free. Unilocular ovary,
with 3–4 parietal placentæ. Fruit a capsule. Embryo straight,
endospermous. Especially in S. Europe, Africa, on the shores of
the Mediterranean and Atlantic.

Order 7. =Tamaricaceæ (Tamarisks).= To this order belong only
_Tamarix_ and _Myricaria_. They are shrubs of a cypress- or
heather-like appearance, as the scattered leaves are very small,
sessile, scale-like or linear, adpressed, entire, and usually
glaucous, and the branches are slender and whip-like. The
flowers are borne in small spikes or racemes, and are small,
reddish or whitish, regular, ☿, hypogynous and polypetalous;
formula S5, P5, A5 + 0 (_Tamarix_, which often has stipular
teeth at the base of the filaments), or A5 + 5 (_Myricaria_,
in which the stamens are united at the base); the number 4 may
appear instead of 5, but in either case there is usually a
tricarpellate gynœceum, which is _unilocular_ and has either
parietal placentæ (_Myricaria_) or a small basal placenta
(_Tamarix_); 1 trifid style, or 3 styles. Capsule dehiscing
along the dorsal suture, and resembling the Willows in having a
unilocular ovary with numerous _woolly_ seeds; but the seed-wool
in this case is borne on the chalaza, and may be attached to a
long stalk.--Some _Tamarix_-species shed part of their branches
in the winter.--40 species; North Temperate, on the sea-shores
or steppes, especially in Asia. Ornamental shrubs: _Myricaria
germanica_, and _Tamarix gallica_.

Order 8. =Cistaceæ.= Shrubs or herbs, natives especially of the Mediterranean region. Flowers generally in raceme-like scorpioid cymes, regular, ☿, hypogynous; sepals 5, free, _twisted_ in the bud, of which the two outer are generally much smaller than the others; petals 5, free, _twisted_ in the bud (in the direction _opposite_ to the sepals), fugacious; stamens _numerous_; gynœceum syncarpous, carpels usually 3–5, style simple, ovary unilocular, with parietal placentation (seldom divided into loculi, with axile placentation). The ovules are _orthotropous_ in opposition to some of the other orders of this family. The capsule dehisces along the dorsal sutures; embyro _curved_. The leaves are simple, undivided, generally opposite and stipulate.--~They are Violaceæ with regular flowers, numerous stamens, and curved embryo. The numerous stamens are in reality only one or two 5-merous whorls, divided into a large number of stamens; these are formed, therefore, in descending order, like the lobes of many compound foliage-leaves.~

_Helianthemum_ (Rock-Rose), has 3 carpels.--_Cistus_ has 5 (-10) carpels.

About 70 species; temperate climates, especially about the
Mediterranean. The resin of the _Cistus_-species has been used
medicinally (ladanum).

Order 9. =Bixaceæ.= This order is closely allied to the Cistaceæ
and Ternstrœmiaceæ; like these it has regular, 5-merous,
hypogynous flowers with numerous stamens, unilocular ovary and
_parietal_ placentæ; sometimes unisexual flowers; it differs in
having anatropous ovules, in the æstivation of the sepals, etc.
All species (about 180) are trees or shrubs, with scattered,
simple leaves, which usually have stipules, and are occasionally
dotted with pellucid oil-glands.--_Bixa orellana_ (Trop. Am.)
is the best known species; it has a 2-valved capsule; the seeds
are enclosed in a shiny _red, fleshy testa_, which contains the
well-known orange or yellow dye, annatto.

Order 10. =Dilleniaceæ.= Gynœceum usually apocarpous, seed
arillate. The flower has most frequently S5, P5, and compound
stamens (one or more bundles); sometimes irregular. 200 species;
Tropical; woody plants, many lianes.--_Dillenia_, _Candollea_,
_Pleurandra_, _Davilla_, etc.

Order 11. =Elatinaceæ= (=Water-worts=). About 25 species belong
to this order; especially in temperate climates. They are small,
creeping, rooted, aquatic plants, with opposite or verticillate
leaves and _stipules_. The flowers are solitary or situated in
small dichasia in the leaf-axils, they are small, regular, ☿,
hypogynous, with free petals, the same number in all 5 whorls
(Sn, Pn, An + n, Gn), 3-merous (_e.g. Elatine hexandra_),
4-merous (_e.g. E. hydropiper_), or 5-merous (_Bergia_); the
corolla-stamens are sometimes suppressed; petals imbricate
without being twisted; the ovary is 3–4–5-locular, with 3–4–5
_free styles_; the capsule dehisces septicidally. The seeds are
orthotropous or curved, often transversely ribbed, endosperm
wanting. The order is most nearly allied to Hypericaceæ, whose
primitive form it appears to represent.

Order 12. =Hypericaceæ= (=St. John’s-worts=). This order is recognised by its always _opposite_ or _verticillate_, _simple_, and entire, penninerved leaves, without stipules, and usually dotted with _pellucid_ glands; by the always ☿, regular, hypogynous flowers in a cymose inflorescence; the generally 5-merous calyx and corolla, with sepals and petals free; the stamens 3–5, numerously branched (Figs. 426, 427); and the gynœceum, 3–5-carpellate, styles usually _free_. The ovary is 3–5-locular, or unilocular with 3–5 parietal placentæ. Fruit a capsule (dehiscing septicidally) or berry. Endosperm absent.

The inflorescence is a _dichasium_ or _helicoid cyme_. The
structure of the flowers is the same as that of the foregoing
orders: S5, P5; succeeding these in some cases are two 5-merous
whorls of stamens in regular alternation, of which the inner
is epipetalous; but the outer whorl is only represented by 5
small scales (Fig. 427), or is altogether absent (_Hypericum
calycinum_, _H. hircinum_), and the inner divided into numerous
stamens, that is, these 5 stamens are so deeply divided that
5 _epipetalous_ groups bearing anthers are found (as in the
Cistaceæ); in other cases the flower becomes _3-merous after
the petals_, stamens 3 + 3 following in regular alternation
(Figs. 426, 427), the outer whorl of stamens in these cases is
also present as staminodes (Fig. 427), or may be altogether
suppressed. Carpels 3–5. _The petals are often twisted_ in the
bud, and are then oblique.

_Hypericum._ Some species have a square stem; in these cases the leaves are placed opposite the edges. Fruit a capsule.--_Vismia_ has a berry.--~The flowers of _Hypericum_ have no honey, and supply only pollen; self-pollination often takes place.~

About 240 species; the tropical ones being often shrubs or
trees; the others generally perennial shrubs.--_Hypericum_,
St. John’s-wort, contains a resinous, red matter, which can be
extracted with alcohol. The American gamboge is the dried sap of
species of _Vismia_.

Order 13. =Guttiferæ=, or =Clusiaceæ=. Closely allied to the
Hypericaceæ and Ternstrœmiaceæ. Leaves opposite or verticillate.
The flowers are often unisexual; stamens united; the gynœceum
has most frequently a sessile, radiating or shield-like stigma.

370 species; chiefly in the Tropics (Am.). They are principally
woody plants and their bark contains a yellow gum resin,
“gamboge,” which is extracted from _Garcinia morella_ (E. Ind.)
and others. Mangosteen (_Garcinia mangostana_ S.E. Asia), and
_Mammea americana_ (W. Ind.), have very delicious fruits.
To this order also belong _Platonia insignis_, _Pentadesma
butyracea_ (the Butter-tree), _Clusia_, _Calophyllum_, _Cataba_,
etc.

Order 14. =Ternstrœmiaceæ.= Trees and shrubs with scattered, simple, and often more or less leathery, evergreen, penninerved leaves, without stipules (Fig. 428). The two most important genera are: _Camellia_ and the closely allied _Thea_ (by some authorities these are united into one genus). The flowers are regular, hypogynous, and situated singly on very short stalks. A number of green floral-leaves are placed below the calyx and gradually pass over into the sepals, and the leaves (5–6) of the calyx again gradually pass over into the corolla (this being especially marked in _Camellia_), of which the number of leaves varies (5, 6, 7 and upwards); the calyx and the corolla are _acyclic_ or _eucyclic_; the petals are slightly united at the base; stamens _numerous_ in many whorls, the external ones are arranged in bundles and united with the petals as in the Columniferæ; gynœceum syncarpous; styles often _free_ nearly to the base; ovary 3–5-locular, ovules numerous in each loculus. The fruit is a woody capsule.--~Other genera show more distinctly than these the same structure as in the preceding orders, namely: S5, P5, A5 + 5, of which the calyx-stamens are often suppressed, and the petal-stamens divided into numerous stamens.--_Kielmeyera_ (S. Am.)~

260 species; especially in the Tropics (E. Asia, Am.) The
leaves of _Thea chinensis_ (or _Camellia thea_), the Tea-tree
(E. Asia), are cultivated for the well-known “tea,” and contain
theine: the best are the young, still hairy leaves, of greyish
colour; there are many varieties. Ornamental plants, _Camellia
japonica_ and _Actinidia_.

Closely allied to this order are: Order 15. =Rhizoboleæ= (with
enormously large hypocotyl--hence the name), and Order 16.
=Marcgraviaceæ= (partly epiphytes, with dimorphic leaves and
cup- or helmet-like, coloured, honey-secreting floral-leaves,
which serve to attract insects).

Order 17. =Dipterocarpaceæ.= This order has taken its name from
the large wings attached to the fruits in _Dipterocarpus_ (the
wings being largely developed sepals); trees and shrubs from
Trop. Asia. 180 species. Camphor ready prepared is found in the
stem of _Dryobalanops camphora_. _Hopea_; _Vateria_.

Family 12. =Gruinales.=

The flowers are hypogynous, ☿, polypetalous, usually regular (except _Pelargonium_, _Tropæolaceæ_, _Balsaminaceæ_) and _throughout 5-merous_: S5, P5, A5 + 5, or 5 + 0, G5 (_epipetalous_). The stamens soon fall off and are _obdiplostemonous_, often united at the base (_monadelphous_); the corolla-stamens are in some completely suppressed (_e.g. Balsaminaceæ_, Fig. 438), in others reduced to teeth (_Linum_, Fig. 431; _Erodium_). The _Tropæolaceæ_ have 3 carpels and only 8 stamens (Fig. 437). Ring-like nectaries are not present, but at most only glandular bodies, borne outside the base of the stamens. Ovaries many-locular. The ovules as a rule are pendulous, with the micropyle directed outwards (Fig. 431, B), and the radicle therefore also points outwards. Usually _herbs_. Related to the Columniferæ.

Order 1. =Oxalidaceæ.= Most of the species are herbs with rhizomes; the leaves are stalked, _compound_, with entire leaflets which are folded and bent backwards in the bud (and in the sleep position), exstipulate; some species have sensitive leaves. The flowers (Fig. 429) are regular, and have S5, P5, which are _twisted_ to the left or right in æstivation, A5 + 5, all united at the base (monadelphous), gynœceum 5-carpellate, _styles 5 free_, stigmas capitate, ovary 5-locular, ovules numerous. The fruit is a _capsule opening_ with clefts _on the dorsal sutures_ through which the seeds are ejected, while the _fleshy, external layer of the testa_ springs off elastically. Embryo straight. Endosperm.

_Oxalis_ (Wood-Sorrel). Leaves digitate. Species also occur
with phyllodia, _i.e._ leaf-like petioles placed vertically
without lamina; a few have pinnate leaves. The flowers are
situated singly or in dichasia, and unipared scorpioid cymes.
The pollination is effected by insects. Some species are
trimorphic (long-, short-, medium-styled flowers) and some,
_e.g. O. acetosella_, have cleistogamic flowers in addition
to the ordinary ones. Glands are found on the outer side of
the corolla-stamens or of all the stamens. _O. tetraphylla_
and others have adventitious edible roots, resembling
tap-roots.--_Averrhoa_ is a tropical tree, with berries and
pinnate leaves.

235 species (205 belong to _Oxalis_); chiefly in S. Africa and
Trop. America.--Oxalate of potash is contained in the leaves of
_Oxalis_.

Order 2. =Linaceæ.= Herbs with scattered or opposite, sessile, _simple_, small, entire leaves, without (rarely with small) stipules. The flowers (Fig. 430) are regular, 5- or 4-merous. Petals are free, _twisted_, quickly falling off. Stamens united at the base; the petal-stamens _are either reduced to teeth_ (Fig. 431 _A_, _m_) _or entirely suppressed_. _Styles free._ The (5–4) epipetalous loculi of the ovary are incompletely halved by _false divisional walls_, each half contains one ovule (Fig. 431 _C_). The fruit is a spherical _capsule, dehiscing along the divisional wall_ (Fig. 432); the 10 (-8) seeds have a straight embryo and very slight endosperm (Fig. 433).

Fig. 430.--The Flax plant.

Fig. 431.--_A_ Flower after removal of sepals and petals; _m_
petal-stamens reduced to teeth. _B_ Longitudinal section of
ovary. _C_ Transverse section of capsule.

Fig. 432.--Capsule (nat. size).

Fig. 433.--Transverse and longitudinal section of seed: _bl_ the
cotyledons; _k_ the plumule; _R_ the radicle; _fr_ the endosperm;
_sk_ the testa.]

_Linum_ (Flax) has 5-merous flowers. ~The main axis terminates in a flower; and the succeeding branching is cymose, or unipared scorpioid branching by unilateral development, and the flowers in consequence of the vigorous sympodial development of the lateral axis (and also by the leaves being displaced and pushed aside), assume a position apparently lateral (_i.e._ racemose) without bracts; each branch of the sympodium generally has 2 leaves. The testa is shining and smooth when dry, but its external cellular layer becomes mucilaginous in water.~--_Radiola_ has a 4-merous flower. It is a small herb with opposite leaves, and regular, dichasial branching.

The anthers and stigmas in _L. catharticum_ and _usitatissimum_
develop simultaneously, and cross-pollination as well as
self-pollination takes place. _L. grandiflorum_, _perenne_,
and others, are dimorphic (short-and long-styled). There are 5
nectaries outside the stamens.

130 species; _Linum_ and _Radiola_ are native genera.--_L.
usitatissimum_ is extensively cultivated in Europe (especially
in Russia and Belgium), N. America and elsewhere (its home no
doubt being Asia), partly on account of the oil (linseed oil)
which is extracted from the seeds, and partly on account of
the bast of the stem, which has very thick-walled cells. The
seeds and oil are OFFICINAL. The species cultivated in ancient
times was _L. angustifolium_. Several species are cultivated as
ornamental plants.

Order 3. =Geraniaceæ.= The majority are herbs with dichasial branching, and scattered or opposite, stalked, _palminerved_ (rarely penninerved) leaves with small _stipules_. The flowers are regular (except _Pelargonium_) and 5-merous, with 10 or 5 stamens, which are slightly united at the base. Nectaries alternate with the corolla-stamens. The ovary is most frequently 5-locular, deeply 5-grooved, and bears 1 _well developed style_ (“beak”), which towards the apex divides into 5 branches bearing stigmas; ovules 1 in each loculus, pendulous or ascending. _The 5 carpels become detached from one another when ripe_, and bend or _roll back_ (Fig. 434) or become _spirally twisted_ in the upper “beak-like” part (Figs. 435, 436), whilst a _central column_ (septal column) persists; each carpel, in consequence, remains either closed, and the fruit is a 5-merous _schizocarp_ whose nut-like lower portion, containing the seed, is forced into the ground, thus burying the seed by the movements of the spirally-twisted, hygroscopic “beak” (Figs. 435, 436); or it opens along the ventral suture, so that the seeds may fall out, and it is then a 5-valved _capsule_, with septicidal dehiscence (Fig. 434) and the rolling up often takes place so suddenly and violently that the seeds are shot out to considerable distances. The embryo is usually green and _curved_, and the _cotyledons are folded_; endosperm is wanting.

_Geranium_ (Crane’s-bill) has 5 + 5 stamens,and a septicidal capsule; the carpels most frequently remain suspended from the apex of the column (Fig. 434). The leaves are most frequently palminerved. The flowers are situated solitarily or 2 together (2-flowered scorpioid cyme).--_Erodium_ (Stork’s-bill); inflorescence a many-flowered unipared scorpioid cyme, stamens 5 + 0 (petal-stamens are wanting), and fruit a schizocarp whose carpels become detached; their beaks are hairy on the internal surface and _twist themselves spirally_ (Fig. 436). The umbellate inflorescences are composed of multiflowered scorpioid cymes. The leaves are often penninerved.--~The most primitive type is represented by _Biebersteinia_: S5, P5, A5 + 5, G5 (ovaries _free_, and styles united above); fruit 5 small nuts. The most advanced type is _Pelargonium_, which has _zygomorphic_ flowers, the posterior sepal being prolonged into a spur which becomes adnate to the peduncle; the petals are unequal in size; some of the petal-stamens are often wanting. (_Erodium_ may be slightly zygomorphic).~

POLLINATION. The large-flowered _Geranium_-species are
protandrous, _e.g. G. pratense_ (one whorl of stamens opens
first, and then the other, and succeeding these the stigmas,
after shedding the pollen the stamens bend outwards); the
small-flowered are also adapted, with various modifications,
for self-pollination.--470 species; moderately hot climates,
especially S. Africa.--Several _Pelargonium_-species, with
numerous varieties, are ornamental plants (from S. Africa).

Order 4. =Tropæolaceæ.= Herbaceous, juicy plants which have scattered, long-stalked, peltate leaves without stipules, and often climb by their sensitive petioles. The flowers are situated singly in the axils of the foliage-leaves on long stalks, and are _zygomorphic_, the receptacle under the posterior sepal being prolonged _into a spur_; there are also differences between the posterior and anterior petals, the 2 posterior petals situated on the border of the spur being _perigynous_, and the edge of the anterior petals adjoining the claw fringed. After the 5 sepals (which are more or less coloured) and the 5 petals, follow 8 _stamens_ (as the 2 median ones are suppressed, one from each whorl) and a gynœceum formed of 3 carpels; in each of the 3 loculi of the 3-grooved ovary is 1 ovule. The fruit is a _schizocarp_ and divides into 3 1-seeded, _drupe-like_ fruitlets, which do not (as in the Geraniaceæ) leave any pronounced column between them. Endosperm is wanting. The cotyledons are thick and sometimes slightly coalescent. ~Tubers often occur.~

_Tropæolum._--About 40 species; all from America.

POLLINATION.--The spur is the receptacle for the nectar; the
flowers are protandrous; the anthers open first, and one by
one take up a position in front of the entrance to the spur,
resuming their original position when the pollen is shed; the
stigma finally takes their place after the filaments have bent
backwards.--These plants have an acrid taste (hence the name
“Nasturtium,” “Indian Cress”), on which account the flower-buds
and young fruits of _T. majus_ are used as capers. Some species
are ornamental plants.

Order 5. =Balsaminaceæ.= Herbaceous, chiefly annual plants with juicy, brittle stems, so transparent that the vascular bundles may be distinctly seen. The leaves are simple, usually scattered, penninerved and dentate; stipules are wanting, but sometimes large glands are present in their place at the base of the petioles. The flowers are strongly zygomorphic; of their five 5-merous whorls the petal-stamens are suppressed (S5, P5, A5 + 0, G5); the sepals are _coloured_, the 2 _anterior ones_ (Fig. 438 _3_, _5_) _are very small_ or entirely suppressed, _the posterior one_ is very large and _elongated into a spur_, and the 2 lateral ones pushed forward; sometimes the weight of the spur turns the flower completely round, so that the posterior leaves assume an anterior position; apparently only 3 petals, since the lateral and the posterior petals become united in pairs, and the anterior is larger and differently shaped; the 5 stamens have very short and thick filaments united at the base, and their anthers finally adhere together and remain in this condition, covering over the gynœceum; the filaments ultimately rupture at the base, and the entire anthers are raised on the apex of the gynœceum as it grows up. The gynœceum has a _sessile stigma_ and a 5-locular ovary. The fruit is a capsule which, on maturity, opens suddenly when irritated, dividing into valves from the base upwards, and as the 5 valves roll up elastically, the seeds are shot out on all sides to considerable distances; a central column persists (Fig. 439). The embryo is straight, and without endosperm.

_Impatiens_; in Europe only _I. noli-me-tangere_. 225 species;
especially from Asia. Several species have two kinds of flowers:
small, cleistogamic, but fertile; and large, coloured flowers,
which in _I. balsamine_ (ornamental plant, E. Ind.) are
protandrous and pollinated by hive-and humble-bees, as they suck
the honey from the spur.

Order 6. =Limnanthaceæ.= The flowers are regular and differ
from all the other orders in the family by having the carpels
not in front of the petals, but _in front of the sepals_
(which are _valvate_), and further, the loculi are nearly
_free individually_, but with a _common gynobasic_ style;
the ovules are _ascending_ and _apotropous_ (anatropous with
ventral raphe). The fruit is a schizocarp, with nut-like
cocci.--_Limnanthes_ (4 species; N. Am.) perhaps belongs to
another family.

Order 7. =Humiriaceæ.= Trees and shrubs; about 20 species; Trop.
Am.

Family 13. =Columniferæ.=

The chief characteristics of the orders belonging to this family are the ☿, regular, generally 5-merous, _hypogynous_ flowers with 5-merous _calyx_, sepals united and _valvate_ in the bud; petals 5, free (often _twisted_ in the bud); stamens ∞ _e.g._: 10, in two whorls, but one of these is more or less suppressed, often altogether wanting, or replaced by 5 staminodes, while _the other_ (inner whorl) _is generally divided more or less deeply_ into a large number of anther-bearing filaments. The filaments too (except _Tiliaceæ_) are _united into a tube_, which, especially in the _Malvaceæ_, forms a long column in the centre of the flower, surrounding the gynœceum (Figs. 445, 448); in this case, which is the most pronounced, the filaments are united into one bundle (_monadelphous_), in other instances, _polyadelphous_. The number of carpels varies greatly (2 to about 50), but they are nearly always united and form a syncarpous multilocular gynœceum.--The vegetative characters also closely agree, the leaves _are always scattered and generally stipulate_; all the green portions very often bear _stellate hairs_, and the bark in all the 3 orders is _rich in tough bast_. Mucilage is often present in cells or passages.--This family is connected with the _Ternstrœmiaceæ_, from which it is very hard to draw a sharp line of demarcation, and it is also allied to the _Cistaceæ_ and to the _Gruinales_.

Order 1. =Sterculiaceæ= (including Buettneriaceæ). This is, no doubt, the least modified order, and one in which the stamens occur undivided. Obdiplostemonous. The 10 stamens in two whorls are most frequently united at the base into a short tube, and have _4-locular, extrorse_ anthers. The calyx-stamens are nearly always simple, tooth-like staminodes, situated on the edge of the tube, or are entirely suppressed. The same relation is found, for instance, in the Ampelidaceæ and Rhamnaceæ, namely _5 stamens in front of the 5 petals_; not infrequently the 5 stamens are doubled (Fig. 441). Unisexual flowers are found in _Sterculia_, _Cola_, _Heritiera_. The corolla is often wanting, or developed in an unusual manner. Each loculus of the ovary (generally 5) always contains more than one ovule. Fruit a capsule. Androgynophore often present (_Helicteres_; _Sterculia_, etc.).

_Hermannia_, _Mahernia_, _Melochia_, etc., have flat petals
with twisted æstivation; 5 undivided stamens, which usually
are but slightly united at the base, and most frequently,
without staminodes. _Thomasia_; _Helicteres_; _Sterculia_
(free follicles).--_Theobroma_, _Rulingia_, _Buettneria_,
_Commersonia_, _Guazuma_, etc., have petals concave at the
base, and terminating in a limb abruptly bent back, and at the
boundary between them most frequently ligular outgrowths, as in
certain genera of the Caryophyllaceæ; stamens 5–15–∞, anthers
at the edge of a short tube and 5 linear staminodes (Fig.
441).--The Cocoa-tree (_Theobroma_), (Fig. 440) bears large,
reddish-yellow, berry-like fruits, resembling short cucumbers,
but ultimately becoming leathery to woody; in each of the 5
loculi are 2 (apparently only 1) rows of horizontal, oily seeds,
as large as almonds. Cotyledons large, thick, and irregularly
folded. Endosperm absent (Fig. 442).

49 genera, with about 750 species; almost entirely confined
to the Tropics; none in Europe or in N. Asia.--The seeds
of the Cocoa-tree (_T. cacao_, _bicolor_, _glaucum_, etc.,
natives of Trop. Am., especially north of the Equator) are
used for chocolate and are also _officinal_ (“Cocoa-beans,”
“Cocoa-butter,” “Oil of Theobroma”). Theobromine. _Cola
acuminata_, Africa.

FIG. 441.--Diagram of the flower: _st_ barren stamens.

FIG. 442.--_B_ Seed in transverse section: _n_ hilum. _A_ Embryo
after the removal of one of the cotyledons.]

Order 2. =Tiliaceæ.= This differs from the other orders of the Columniferæ chiefly in the stamens being entirely _free_ from each other, and also _divided_ into many filaments, _as far as the base_, or at all events very far down, so that the _flower appears to have numerous stamens_ or to be _slightly_ polyadelphous (Fig. 443); in addition to this, it may be observed that the anthers are _4-locular_ and _introrse_. In _Luehea_ the groups of stamens alternate with the petals. In a few genera (_Corchorus_, _Triumfetta_) 10 free and single stamens are found in 2 whorls; but, in the majority, groups of free stamens in separate bundles. The stamens are more or less united in _Apeiba, Luehea_. Style simple. Ovary 2-locular. The ovules are pendulous; raphe turned inwards. The calyx readily falls off; the æstivation of the entirely free petals is slightly imbricate (_not twisted_).

_Tilia_ (Figs. 443, 444). Calyx and corolla 5-merous; the 5 staminal leaves (opposite the petals) divided as far as the base into a large number of stamens which are free or united into groups; gynœceum with 5 loculi in the ovary (opposite the sepals); there are 2 ovules in each loculus, though the ovary ripens into a 1-seeded nut, which is not detached from the axis of the inflorescence, but is carried away by the wind, whirling round and round, its large-winged bracteole serving as a parachute (Fig. 443).--~Only trees, with alternate, obliquely heart-shaped and dentate leaves; stellate hairs, as in the other Columniferæ, are often present. The terminal bud of the branch always fails to develop, and the growth is then continued sympodially by the uppermost axillary buds. The INFLORESCENCE (Figs. 443, 444) is a 3–7-flowered dichasium (Fig. 444 _t_, _d_, _e_), which is developed in the axil of a foliage-leaf (Fig. 444). The first of its 2 bracteoles (_a_) is large, thin, leaf-like, and united with the inflorescence, the lower portion of which forms a broad wing, its so-called “bract”; the second bracteole (_b_), on the other hand, remains scale-like, and supports a winter foliage-bud covered with bud-scales which thus is situated at the base of the inflorescence, and is a bud of the 2nd order, in relation to the vegetative shoot. This bud is always found beneath the inflorescence on the branch placed horizontally, and the winged bracteole is always found above it, a relation which is connected with the fact that the 2 rows of shoots on the sides of a branch are _antidromous_ with regard to each other.--The dichasium itself (Fig. 444) terminates with the flower (_t_); it has 3 floral-leaves (_c_, _d_, _e_), which soon fall off; _c_ is barren: the other two bear flowers, or few-flowered dichasia, or unipared scorpioid cymes (indicated in the figure).--The foliage-leaves are folded in the bud upon the median line (1, 2, 3 in Fig. 444 are foliage-leaves with their 2 stipules), the inner half is broader than the outer, and after unfolding is turned away from the mother-axis (the position of the new inflorescences and vegetative buds is indicated in their axils on the figure).--The cotyledons on germination appear above the ground as large, _lobed_ leaves.~