Chapter II: ACROGYNÆ. The apex of the stem or of certain branches is adapted (12)

=A.= PENTACYCLICÆ (FIVE-WHORLED). The flowers in this section have 5 _whorls equal in number_, namely, 2 staminal whorls in addition to the calyx, corolla, and carpels; in some instances, one of the staminal whorls is rudimentary or entirely suppressed, but in this case it is frequently the sepal-stamens which are suppressed, and the whorl which is present stands opposite the petals. The flowers are regular. The _number of carpels equals that of the sepals_, but in one of the orders (_Bicornes_) they are opposite the petals (the flower being obdiplostemonous); in the other two orders (_Primulinæ_ and _Diospyrinæ_) they are placed opposite the sepals (the flower being diplostemonous). This section is the most closely allied to the Choripetalæ, since the petals may sometimes be found entirely free, and the stamens inserted directly on the receptacle (Ericaceæ); ovules with two integuments are also found. ~It is very doubtful, whether the orders included under this head have any relationship with the other Sympetalæ. They appear in any case to represent older types.~

=B.= TETRACYCLICÆ (FOUR-WHORLED). The flowers have only 4 whorls, namely, beside sepals, petals, and carpels, only one whorl of stamens, which alternates with the petals; there is no trace of the second staminal whorl, and when the number of carpels is the same as that of the preceding whorls (“isomerous”) they alternate with the stamens; but in most cases there are 2 _carpels placed in the median plane_ (see the diagrams, _e.g._ Figs. 559, 567, 583, 590, etc.). This section is the largest, and the one which shows the characteristics of the Sympetalæ best. Very irregular flowers are met with.

The following families belong to the =Pentacyclicæ=: 26, _Bicornes_; 27, _Diospyrinæ_; 28, _Primulinæ_.

The remaining families belonging to the =Tetracyclicæ= are:--

=a.= HYPOGYNOUS flowers (with a few exceptions): 29, _Tubifloræ_; 30, _Personatæ_; 31, _Nuculiferæ_; 32, _Contortæ_.

=b.= EPIGYNOUS flowers: 33, _Rubiales_; 34, _Dipsacales_; 35, _Campanulinæ_; 36, _Aggregatæ_. The ovaries and ovules in the last family are always reduced to one; and at the same time the fruits become nuts, and the flowers are united into crowded inflorescences.

A. Pentacyclicæ.

Family 26. =Bicornes.=

This family is chiefly composed of shrubs, less frequently of small trees, or perennial herbs; their leaves are undivided, most frequently evergreen, stiff and leathery, and always without stipules. The flowers are ☿ and _regular_, rarely slightly zygomorphic, most frequently obdiplostemonous, and 4- or 5-merous through all the 5 whorls. _The stamens are attached to the receptacle_, and as a rule are quite free from the petals, an attachment which is very rare among the Gamopetalæ. They have a simple gynœceum with _one_ undivided style, a commissural stigma, and a _multilocular_ ovary, whose axile placentæ project considerably into the loculi, and bear a large number of ovules. ~The placentæ are sometimes not united, and in consequence, the ovary is 1-locular with incomplete partition-walls, _e.g._ _Pyrola_, _Monotropa_.~ Embryo straight, with endosperm. _The carpels are placed opposite the petals._

The _diagram_ is generally Sn, Pn, An + n, Gn, in which n is 4 or 5. To this may be added, that the _corolla is in most cases gamopetalous_, but in some (especially _Pyrolaceæ_) perfectly polypetalous; and that the _anthers usually open by pores_, and often have _two horn-like_ appendages (hence the name “Bicornes”) (Figs. 545, 546); frequently the two halves of the anther are also widely separated from each other at the upper end, so that the pores are placed each one at the end of its own tube (Fig. 546); the pollen-grains in the majority are united into _tetrads_ (Fig. 542 _D_).--The flowers, as a rule, are pendulous and borne in racemes, coloured (red or white), but odourless. When the fruit is a capsule, the placenta with the seeds attached persists as a central column. A _mycorhiza_ occurs on many.

The majority of plants belonging to this family inhabit cold and temperate countries, or high mountains in tropical regions; they prefer cold and dry or damp places (bogs, heaths, etc.). Plentiful in N. America.

Order 1. =Pyrolaceæ.= Perennial _herbs_; _petals most frequently quite free from each other_, and falling off singly after flowering; _the anthers are without appendages_, and open by pores (Fig. 544), or by a transverse slit. The placentæ are thick. The seeds in the _capsule-like_ fruit (loculicidal dehiscence) are exceedingly small and light, they have a sac-like testa which loosely envelops them, an oily endosperm, and an _extremely simple embryo_, which consists only of an ellipsoidal, cellular mass, without cotyledons or differentiation into plumule and radicle.

_Pyrola_ (Winter-green) is green, and has also large evergreen foliage-leaves. The flowers, 5-merous, are most frequently borne in racemes without a terminal flower; the anthers are extrorse in the bud with the pores in the lower portion (Fig. 544 _A_), but they become inverted at a later period, so that the pores open at the top (Fig. 544 _C_). ~_P. uniflora_ has a single, terminal flower; it winters by its roots, producing from these in the spring aerial, quite unbranched shoots. _Chimaphila umbellata._~

_Monotropa_ (Yellow Bird’s-nest) is very pale yellow, without chlorophyll, succulent, and has only scale-like leaves closely pressed upon the stem; it is a saprophyte. The raceme has a terminal flower, and is pendulous before flowering. The anthers open by a semicircular, transverse cleft. ~_M. hypopitys_ reproduces chiefly by root-shoots.~

About 30 species, especially N. Europe, N. America, and N. Asia.

Order 2. =Ericaceæ.= The flower (Fig. 545) is _hypogynous_, the median sepal posterior; corolla, _gamopetalous_; the stamens are generally _2-horned_, and the fruit is a _capsule_, less frequently a berry or drupe. At the base of the ovary is a nectar-secreting disc (Fig. 545 _B_). This order comprises shrubs or undershrubs (rarely small trees), which are evergreen, and as a rule have densely crowded leaves.

=1.= ERICEÆ, HEATH GROUP. Flowers most frequently _4-merous_ (S4, P4, A4 + 4, G4, united in a 4-locular gynœceum), rarely 5-merous. The withered corolla _persists_ after flowering. The leaves are most frequently acicular, opposite or verticillate; the buds are without scales. The fruit is a capsule.--_Calluna_ (_C. vulgaris_, Ling) has a deeply 4-cleft corolla, which is less than the coloured calyx; capsule with septicidal dehiscence.--_Erica_ (about 420 species; _E. tetralix_, Cross-leaved Heath) has a tubular or bell-shaped, 4-dentate corolla, which is much longer than the calyx. Capsule with loculicidal dehiscence.--_Pentapera._

=2.= ANDROMEDEÆ. The flowers are 5-merous (S5, P5, A5 + 5, G5), with _deciduous_ corolla. Capsule with loculicidal dehiscence. The leaves are scattered, and incline more to the ordinary broad-leaved forms.--_Andromeda_; _Gaultheria_; _Cassandra (Lyonia)_; _Cassiope_.

=3.= ARBUTEÆ. The flowers as in the preceding group (Fig. 545), but the fruit is a berry or drupe. _Arctostaphylos_ (_A. uva-ursi_, Bear-berry) has a drupe with 5 stones in a dry, farinaceous pulp; in other species there is 1 stone with several loculi. _Arbutus_ (_A. unedo_, Strawberry-tree) has a spherical berry.

_Pollination_ is effected by means of insects, especially by
bees. The pollen is light and dry, and is shaken out through
the pores of the anthers when the insects agitate the horn-like
appendages during their visits. Self-pollination takes place,
no doubt, in many cases.--800 species; the very large genus,
_Erica_, especially in S. Africa (the Cape).--OFFICINAL: the
leaves of _Arctostaphylos uva ursi_. _Arbutus unedo_ (S. Europe)
has an edible, peculiarly warted (strawberry-like) fruit. Many
_Erica_-species are cultivated as ornamental plants.

Order 3. =Rhodoraceæ= (=Rhododendrons=). This differs from the preceding order in the _median sepal being anterior_, and hence the position of the other floral whorls is also reversed. The flower is _hypogynous_, in most cases 5-merous; the corolla is most frequently deeply cleft or polypetalous, and falls off after flowering; the anthers open by pores, and have _no horn-like appendages_. _Capsule_ with _septicidal_ dehiscence.--The shrubs or small trees belonging to this order have, like the Vaccineæ, ordinary foliage-leaves, and the buds are generally provided with _large bud-scales_.

_Rhododendron_ has 10 stamens, and a slightly zygomorphic flower with deeply 5-cleft corolla (the section _Azalea_ has frequently only 5 stamens, the petal-stamens being absent). They are Alpine plants (200 species) in the mountains of Asia, especially the Himalayas; some in S. Europe.--_Menziesia._--_Ledum_; small, rusty-brown, hairy shrubs with polypetalous, expanded, star-like corolla.--_Kalmia_ (N. Am.) has a cupular corolla, with 10 small, pocket-like depressions in which the anthers are concealed until the arched, elastic filaments are freed from this position by means of the insects, when they quickly straighten themselves in the centre of the flower.--_Phyllodoce_; _Loiseleuria_ (5 stamens); (_Clethra_ (?); also placed among the Ternstrœmiaceæ).

About 270 species. Several species are ornamental plants.
Several plants of the order are more or less _narcotic_. _Ledum
palustre_ has been used as a substitute for hops.

Order 4. =Diapensiaceæ.= Hypogynous flower. 3 floral-leaves
beneath the flower (S5, P5, A5 + 0, G3). Stamens on the throat
of the corolla. Pollen-grains single. Disc absent. Capsule
loculicidal.--9 species from the Arctic regions. It is doubtful
whether this order should be included in the Bicornes; perhaps
it would be more correctly assigned to the _Polemoniaceæ_.

Order 5. =Epacridaceæ.= This order comprises those species of
the family which are confined to Australia and the South Sea
Islands. They are shrub-like plants, resembling the Ericaceæ in
habit, in the inflorescence, and in the structure, form, and
colour of the flower. They differ especially in having only
1 _whorl of stamens_ (placed opposite the sepals) and in the
anthers having only 2 loculi, and opening by a longitudinal
slit. Fruit most frequently a drupe (or loculicidal capsule).
_Epacris_-and _Styphelia_-species are ornamental plants. About
325 species.

Order 6. =Vacciniaceæ= (=Bilberries=). _The flower_ (Fig. 546) _is epigynous, the corolla gamopetalous_, and _the fruit a berry_. The latter is most frequently spherical, and bears on its apex the calyx, which is generally very low, almost entire, and with a _disc-like expansion_ inside. The flower is 4- or 5-merous (Fig. 546 _B_, _D_). The anthers have 2 pores, and are most frequently 2-horned (Fig. 546 _F_, _G_). Small shrubs; the leaves are scattered, not needle-like.

_Vaccinium_ (Bilberry, Whortleberry) has an urceolate, gamopetalous, only slightly dentate corolla, and horn-like appendages to the anthers (Fig. 546). ~_V. vitis idæa_ (Cowberry) is evergreen, with flowers in racemes, and bright red berries; _V. myrtillus_ (Bilberry) and _V. uliginosum_ (Bog Whortleberry) both have black berries with a blue bloom, leaves deciduous.~--_Oxycoccus_ has a _polypetalous_ corolla with the petals projecting backwards. Anthers without appendages. ~_O. palustris_ (Cranberry) has a slender, creeping stem, and is evergreen. Dark red berry.~

Pollination essentially the same as the preceding order.--320
species; especially in N. Am. Some are useful on account of
their edible fruits, especially _Vaccinium myrtillus_ and _V.
vitis-idæa_, and in a less degree _Oxycoccus_, etc. The fruits
of _V. myrtillus_ are _officinal_.

Family 27. =Diospyrinæ.=

The flowers are _regular_, gamopetalous, typically diplostemonous, with the same number throughout all 5 whorls, thus: Sn, Pn, An + n, Gn, where n most frequently =5 (4–6), rarely 3, 7 or 8. Of the two whorls of stamens the one opposite the sepals is often present only as rudiments or is entirely suppressed, and the completely developed _stamens are thus placed opposite the petals_. The carpels are generally placed opposite the sepals. The _ovary is multilocular_ with the ovules attached in the inner angles. The fruit is most frequently a _berry_. The seeds are large, generally solitary, or a few in each loculus.--All plants belonging to this family are _trees_ or shrubs with _scattered_, _single_, _most frequently entire_, _penninerved_ and _leathery_ leaves without stipules; the majority are tropical (America, Asia), some are found in N. Am. and the Mediterranean.

Order 1. =Sapotaceæ.= Plants with latex; anthers extrorse, 1
_erect_ ovule in each loculus; fruit a berry; the seeds with
bony, shiny brown testa have a large, lateral hilum. The leaves
are frequently covered with silky hairs.--A useful order in
several respects (400 tropical species). The wood of some
genera, such as _Sideroxylon_ (Iron wood) and _Bumelia_, is as
hard as iron. The latex of _Palaquium_ (_P. oblongifolium_, _P.
gutta_, and other species), _Mimusops_ and _Payena_ (Sumatra,
E. Ind.), is the raw material of _gutta percha_. The following
have very delicious fruits: _Lucuma mammosa_, _Achras sapota_,
_Chrysophyllum cainito_ (Star-apple), etc. The seeds of _Bassia_
(E. Ind.) contain a large quantity of a fatty oil. _Isonandra_,
_Mimusops schimperi_ are often found in the Egyptian royal tombs.

Order 2. =Ebenaceæ.= Plants without latex, often diœcious;
flowers with a more or less leathery perianth. The number of
stamens is sometimes increased (by splitting?); ovules 1–2,
_pendulous_ in each loculus. Fruit a berry.--250 species;
chiefly tropical. Some are well known on account of their
hard and black-coloured heart-wood, _e.g._ _Maba ebenus_ (the
Moluccas) and _Diospyros ebenum_ (Ebony-wood, from Tropical
Asia) and others.--The fruits are edible _e.g._ of _Diospyros
lotus_ (Date-plum, Asia), which is also cultivated as an
ornamental shrub, together with several other species.

Order 3. =Styracaceæ.= The flower is more or less _epigynous_,
and the corolla is almost _polypetalous_. The stamens (by
splitting?) are more than double the number of the petals, and
often united at the base. Stellate hairs are frequent.--235
species; Tropical Asia and America, a few for example in the
East.--OFFICINAL: Gum-benzoin from _Styrax benzoin_ and perhaps
other species (Sumatra and Siam). _Halesia tetraptera_ (N. Am.)
is an ornamental shrub with 4-winged fruits.

Family 28. =Primulinæ.=

The flowers are _regular_, ☿, _hypogynous_, and gamopetalous. The _stamens_ are _equal in number_ to the petals (Fig. 547) and _are placed opposite to them_. The ovary is _unilocular_, with _a free, central_ placenta with 1–many ovules.--The flower is a further development of the Diospyrinæ; the suppression of the calyx-stamens, which commenced in this family, is carried further in the Primulinæ, so that in the majority of cases no trace of them is present, but in certain species and genera (_Samolus_, _Lysimachia thyrsiflora_, _Soldanella_, certain Myrsineæ) some small bodies (scales, teeth, etc.) are found in the position of the suppressed stamens. Again, the lateral portions of the carpels are suppressed, so that the _ventral placentæ_ with the ovules are separated from the dorsal portions, and _are united into a free central placenta_; this theory is supported by the branching of the vascular bundles, the development, and various comparative considerations.--Sn, Pn, A0 + n, Gn; where n = 4–8, generally 5. The carpels are placed opposite the sepals (Fig. 547).

Order 1. =Primulaceæ= (=Primroses=). This order has _many ovules_ attached to a _thick, free, central placenta_ (Fig. 547); _style undivided_ with a _capitate_ stigma; ovules semi-anatropous; fruit a _capsule_ with many seeds.

All the plants belonging to this order are _herbs_; stipules wanting; the flower is most frequently 5-merous (S5, P5, A0 + 5, G5; except _Centunculus_ and _Trientalis_). The corolla and capsule have various forms, but the capsule generally opens by teeth at the apex. The ovules are semi-anatropous (in _Hottonia_ they are anatropous), and the seeds are therefore _peltate_, with the hilum situated in the centre of one side. The endosperm is fleshy or horny. The flowers are borne either in racemes or in umbels; as _bracteoles are typically_ absent (Fig. 547), cymose branching does not occur.

_Primula_ (Primrose) has most frequently a vertical rhizome, bearing a rosette of leaves at its summit, and long-stalked umbels; corolla _rotate_ or slightly funnel-shaped; the capsule opens at the apex by 5 _teeth_. The flowers in some species are heterostyled (long-styled or short-styled; Fig. 548). Closely allied are _Androsace_ (with ovate, cup-shaped corolla-tube and ligular scales, alternating with the corolla-lobes) and _Soldanella_ (funnel-shaped corolla with laciniate lobes and most frequently ligular scales).--_Hottonia_ (Water-Violet) is an aquatic plant with pectinate leaves and heterostyled flowers.--_Cortusa._ _Dodecatheon._ _Cyclamen_ (Fig. 549) has solitary, long-stalked flowers, and a rotate corolla with the lobes reflexed; the stalk of the capsule rolls up spirally; the tuberous rhizome is formed by the hypocotyledonary internode. Only 1 cotyledon.--_Lysimachia_ (Money-wort); stem-internodes well developed, leaves opposite or verticillate, calyx almost polysepalous, corolla deeply 5-partite (Fig. 550). The flowers are solitary or in racemes.--_Anagallis_ (Pimpernel), leaves opposite, flowers solitary; the fruit a pyxidium (Fig. 551); similarly in _Centunculus_, which is 4-merous.--_Trientalis_, the flowers are most frequently 7-merous.--_Glaux_ (Sea Milk-wort) is a creeping maritime plant with opposite leaves; flowers solitary in the leaf-axils, _corolla absent_, but with coloured calyx. ~The petals are usually developed later than the stamens in the Primulaceæ; but in this instance they are entirely suppressed.~--_Samolus_ (Brookweed) differs from all the others in having an _epigynous_ flower; barren sepal-stamens are also present. The bracts in the racemose inflorescences are displaced along the flower-stalks.

POLLINATION. Insect-pollination in the majority;
cross-pollination is promoted in some by heterostyly (Fig.
548).--300 species; especially in northern temperate zones;
the majority on mountains (_Soldanella_, _Androsace_, etc.);
almost absent in the Tropics. A large number are ORNAMENTAL
PLANTS, _e.g._ _Primula auricula_ (from the Alps), _P. sinensis_
(China), _P. elatior_ (Oxslip, a native) and _grandiflora_, etc.
_Cyclamen europæum_ (Alpine Violet); the tubers are poisonous.

Order 2. =Myrsinaceæ.= Trees or shrubs; evergreen, tropical
Primulaceæ with fleshy fruits and few seeds, embedded in the
placenta. The leaves are nearly always dotted with yellow
glands (schizogenous resin-receptacles).--550 species;
especially Am.--ORNAMENTAL PLANTS: _Ardisia crenulata_ (W.
Ind.); other genera: _Clavija_, _Maesa_, _Theophrasta_ (barren
sepal-stamens), _Myrsine_, _Jacquinia_ (barren sepal-stamens),
etc.--_Ægiceras_, allied to this order, comprises arborescent
plants, often growing with _Rhizophora_ in tropical forests,
along the shore. The embryo germinates while still in the fruit.

Order 3. =Plumbaginaceæ.= This order has a position of the stamens similar to that in Primulaceæ (S5, P5, A0 + 5, G5), but it differs from these in the flower, which has generally a _membranous_, dry, thin, coloured, folded, almost entire calyx and an _almost entirely polypetalous corolla_, which, as a rule, has twisted æstivation and is _only united_ with the stamens _at its base_; but more especially it differs in the ovary, which bears 5 _free_ or almost free _styles_ and only 1 _basal_ ovule with a _long_, twisted funicle (the placenta of the Primulaceæ is here so much reduced that it bears only 1 ovule). The fruit is a _nut_ or _capsule_. The radicle is turned outwards. Endosperm mealy.--To this order belong herbs or under-shrubs, which are especially natives of the sea-coast and of salt-steppes; they also resemble the Primulaceæ in the scattered, undivided, entire leaves (without stipules), often in rosettes, and the inflorescence borne on a long stalk. In opposition to the Primulaceæ, the _bracteoles are typically present, and hence the branching is generally cymose_ (scorpioid).

_Armeria_ (Thrift) has a round _capitulum_, composed of closely-packed dichasia, surrounded at its base by an involucre with peculiar prolongations, directed downwards, and united into a sheath protecting the intercalary zone of growth. The pericarp is finally ruptured at the base, and drops off like a hood.--In _Statice_ (Sea-lavender), the unipared scorpioid cymes are prolonged and collected into panicle-like inflorescences.--~_Plumbago_ is the genus which approaches nearest to the Primulaceæ, and differs most from the characters given above. It has capitate or spike-like inflorescences, a salver-shaped corolla, and the stamens are not attached to the corolla. The style is only divided at the extremity; the calyx is not membranous, but is covered with sticky, glandular hairs.~

250 species; chiefly in the Mediterranean and about the Caspian
Sea, on salt-steppes and beaches. Some are Tropical; a few are
ornamental plants.

B. Tetracyclicæ.

a. Tetracyclicæ with hypogynous flowers.

Family 29. =Tubifloræ.=

The flower is regular, ☿, and _hypogynous_. The gamopetalous type is present in this family with great uniformity, without suppression or splitting; S5, P5, A5, G2 (3–5). The stamens are all fertile, alternating with the lobes of the corolla. Gynœceum with 2, more seldom 3–5 syncarpous carpels. Style nearly always simple; 2 dorsal stigmas. In each carpel 2–∞ ovules. At the base of the ovary is found a yellowish ring-like nectary (Fig. 552 C), sometimes 5-sinuate or 5-partite.--The leaves are nearly always scattered; stipules are absent.--~The Solanaceæ, which formerly were classed here, are so closely allied to the Personatæ, that it would be unnatural not to place them first in this family; and the Boraginaceæ (which were also placed in the Tubifloræ) appear to be best united, with the Labiatæ and others, into one family Nuculiferæ.~

Order 1. =Polemoniaceæ.= The flowers are regular; S5, P5,
A5, G3. The calyx and corolla have united leaves, the petals
_twisted_ to the right in _æstivation_ (all the left edges
being covered). The ovary is 3-locular with 2–∞ ovules in
each loculus; the style is trifid at the apex; the fruit
is a 3-valved capsule. Embryo straight; endosperm fleshy.
The inflorescences are dichasia passing over into unipared
helicoid cymes (the shoot of the _lower_ bracteole being the
more strongly developed).--Herbs without latex. 150 species;
especially Western N. Am.--_Phlox_ (salver-shaped corolla;
entire, opposite leaves), _Polemonium_ (campanulate or almost
rotate corolla; scattered, pinnate leaves), _Leptosiphon_,
_Gilia_, _Collomia_, _Cobæa_ (climbing, like the Vetches, by
tendrils at the ends of the leaves), etc. They are frequently
ornamental plants.

Order 2. =Hydrophyllaceæ.= This order approaches very closely to
the Boraginaceæ. Herbs with pinnate or palmate leaves; S5, P5,
A5, G2. The lobes of the corolla are imbricate in æstivation.
Generally 2 median carpels. The ovary is _most frequently
unilocular_, and the seeds are situated on 2 _parietal
placentæ_; capsule 2-valved; embryo straight; endosperm fleshy.
In the corolla-tube, opposite the corolla-lobes, there are
frequently appendages of various forms, which resemble those of
_Cuscuta_. The inflorescences correspond exactly with those of
the Boraginaceæ, being _unipared scorpioid cymes_, which, prior
to opening, _are tightly rolled up_.--130 species, especially in
N. Am. (California, etc.). Many annual species of _Phacelia_,
_Nemophila_, _Whitlavia_, _Eutoca_, _Cosmanthus_, etc., are
cultivated in gardens as ornamental plants. _Hydrolea_ (has a
bilocular ovary, and two free styles).

Order 3. =Convolvulaceæ= (=Bindweeds=). The flower is regular, hypogynous, with 5 almost free sepals (quincuncial æstivation), P5, A5, G2 (rarely 3–5). The _corolla_ is very characteristic; it is (with various forms) almost entire, or slightly 5-lobed, and _folded_ longitudinally _in the bud_ in such a way that 5 projecting, flat portions, tapering towards the top and frequently differing in colour and hairiness from the rest, are visible externally and applied close together, while the remainder of the corolla is folded inwards (Fig. 552 A); and hence the whole corolla is _strongly twisted to the right_ in the bud. The gynœceum most frequently has a bilocular ovary; _in each loculus_ there are _only_ 2 (erect) _anatropous ovules_ on the placenta, which is not especially thickened (Fig. 552 _D_, _E_); each loculus is sometimes divided into two by a false septum (a relationship with the _Boraginaceæ_, etc.); style simple with most frequently a bilobed stigma, or a bipartite style. The fruit is nearly spherical, most frequently a _capsule_. The seeds are erect, and have a large hilum at the base. The embryo is _curved_, with leaf-like, thin, bilobed, most frequently folded cotyledons; _endosperm absent or mucilaginous_.

=1.= CONVOLVULEÆ, BINDWEED GROUP. The majority are _twining_ (to the left) _herbs_, with _latex_. The leaves are scattered, without stipules, often long stalked, and nearly always with cordate base; some are palmately lobed. The flowers are most frequently solitary in the leaf-axils, large, quickly withering.--_Convolvulus_ (Fig. 552), _Calystegia_ (unilocular ovary, 2 large bracteoles), _Ipomœa_, _Batatas_, _Evolvulus_ (with a doubly bifid style), _Calonyction_, _Pharbitis_, etc.

=2.= DICHONDREÆ. This group is a more primitive form, not twining, and without latex. It has 2 _free_ carpels with basal style (as in Boraginaceæ) and valvate corolla.

=3.= CUSCUTEÆ, DODDER GROUP (Fig. 553). Parasites, with round, filamentous stems, bearing only scale-like leaves and almost destitute of chlorophyll (they are reddish or yellowish); they are parasitic upon other plants, around which they twine, first with narrow, compact coils from which haustoria (Fig. 553 _A_) are developed which enter the host-plant, and then with wider coils by which they raise themselves to other portions of their host or try to reach other plants. On germination a very temporary primary root is developed, which bears root-hairs as far as the tip (rootcap is wanting); it only serves as a kind of reservoir for water, and perishes very soon after the seedling has fastened on to a host. The embryo is filamentous and rolled up _spirally_ (Fig. 553 _C_), and is sometimes destitute of cotyledons. The flowers are crowded into capitulate inflorescences, complicated by accessory shoots (Fig. 553 _A_); they have S5, P5 (_imbricate_ æstivation), A5 (and beneath the stamens 5 scales on the corolla-tube), G2. Fruit a capsule opening by a lid.--_Cuscuta europœa_, _C. epilinum_ (Flax-Dodder), _C. epithymum_ (Lesser-Dodder), _C. trifolii_ (Clover-Dodder), etc., are parasitic on different hosts, or parasitic each on its own particular host.

840 species; the majority in the Tropics, especially Am. Many
are ornamental plants. OFFICINAL: some on account of their
purgative properties: the tuberous roots of _Ipomæa purga_
(Jalap, from Mexico) and the dried latex (“Scammony”) of
_Convolvulus scammonia_ (from the East). The tuberous roots of
_Batatas edulis_ (Trop. S. Am.) are used as a common vegetable
(Sweet Potato) in the Tropics.

Family 30. =Personatæ.=

The type of the flower is: S5, P5, A5 (of which one, or in some cases several, are suppressed), and G2. The flowers are _hypogynous_, ☿, perfect with gamopetalous corolla, but most frequently irregular (medianly zygomorphic, except _Solanaceæ_), the _corolla_ being _bilabiate_ (divided into a posterior part of two lobes and an anterior part of three lobes), and the _stamens_ 4, _didynamous_ (the posterior being suppressed). The ovary has 2 loculi (only 1 in _Utriculariaceæ_, _Gesneriaceæ_, _Orobanche_); the placenta in the first-named orders (1–7) is most frequently very thick, and bears a _great many ovules_ (Figs. 554, 555, 557, 562); the number of ovules in the last orders (8–9) is considerably reduced (Fig. 570).

Special mention may be made of the apparently 4-merous flower which is found, _e.g._ in _Veronica_ and _Plantago_ (Figs. 567, 562 _C_, 570, 571), and which arises from the typical 5-merous flower by the suppression of the posterior sepal and the posterior stamen, and by the union of the two posterior petals into one.--Terminal flowers very seldom occur on the main axis, and would not harmonise well with the very irregular form of the flower. When they do occur, they are, as a rule, “peloric,” _i.e._ regular (in _Linaria vulgaris_ two kinds of peloric flowers occur,--one with 5 spurs, and one without spurs). The halves of the anthers are often divided as far as the base, and laterally so widely separated from each other as to assume an almost straight line (Figs. 563, 564). There is generally a nectary (“disc”) round the base of the ovary, often 5-lobed (or divided into free glands).--A common vegetative characteristic is the _absence of stipules_.

The 9 orders of the Personatæ are: 1, Solanaceæ; 2, Nolanaceæ;
3, Scrophulariaceæ; 4, Utriculariaceæ; 5, Gesneriaceæ; 6,
Bignoniaceæ; 7, Pedaliaceæ; 8, Acanthaceæ; 9, Plantaginaceæ.

Order 1. =Solanaceæ.= The flower (Figs. 554, 555, 559) is hypogynous, regular (zygomorphic in _Hyoscyamus_), ☿, and gamopetalous, with S5, P5 (most frequently _imbricate_ or _valvate_), A5, G2, the 2 carpels being placed obliquely (Fig. 554); the bilocular ovary has a very _thick axile placenta_ (Figs. 554, 555 _H_, 557), which extends almost as far as the wall of the ovary. The fruit is a capsule or berry; the seeds are more or less reniform, and the embryo is _curved_ (rarely straight), in a fleshy endosperm (Figs. 555 _F_, _G_; 561).--Both arborescent and herbaceous forms are found in the order; leaves scattered without stipules, but with variously formed laminæ (always penninerved). _A peculiar leaf-arrangement_ is found in many species, viz. the leaves are borne _in pairs, a large and a smaller one together_; these pairs stand in 2 rows, and the flowers are then situated _between_ the individual leaves in each pair, apparently _not_ in a leaf axil. The inflorescences are frequently unipared scorpioid cymes without floral-leaves.

Zygomorphic flowers occur, and thus form a transition to the
closely allied Scrophulariaceæ; the zygomorphy sometimes
shows itself only in the relative length of the stamens,
sometimes also in the corolla (_Hyoscyamus_).--_Nicandra_ is
5-merous throughout all the whorls.--The peculiar relative
_leaf-arrangement_ in this order occurs from sympodial branching
and displacement. The most simple is, _e.g._ _Datura_ (Fig. 556
_A_); each shoot-generation in the floral parts of the plant has
only 2 foliage-leaves (_f^1_ and _f^2_), and then terminates
in a flower; the axillary buds of both the foliage-leaves
are developed and form a dichasium, but since the leaves are
displaced on their axillary-shoots as far, or almost as far, as
the first leaf of these axillary-shoots, the flowers are borne
singly on the dichasial branches, and all the branches appear to
be without subtending leaves (Shoot I is white, II shaded, III
white, etc., diagram _A_). _Scopolia_ and others (Fig. 556 _B_)
differ in that the lowest and smallest (_f^1_) of the two leaves
on each shoot is barren, and is therefore not displaced; but the
upper one (the second bracteole, _f^2_) is displaced as in the
first instance, and consequently it assumes a position near the
first leaf (the shaded leaf _f^2_ of shoot I being placed near
the white leaf _f^1_ of shoot II, etc.,) of the next youngest
shoot-generation, and hence the leaves are borne in pairs; the
flower placed between the two leaves of a pair is therefore the
terminal flower of the shoot to which the smaller of the two
leaves belongs, and the larger leaf is the subtending leaf for
the floral shoot itself.

=A.= FRUIT A CAPSULE. _Nicotiana_ (Tobacco) has a 2-valved capsule with septifragal dehiscence; the valves separate at the apex; the corolla is funnel-shaped, tubular, salver-shaped or campanulate. The flowers in panicles.--_Datura_ (_D. stramonium_, Thorn-apple) has a (frequently spiny) capsule (Fig. 558), which is _falsely 4-locular_ (at the top, bilocular) and opens septifragally with 4 valves. The lower part of the calyx persists as a thick collar (see Fig. 558). The corolla is funnel-shaped. The flowers are solitary, large.--_Hyoscyamus_ (_H. niger_, Henbane) has a pyxidium (Fig. 557) enclosed in the campanulate, completely persistent, thick-walled calyx. The flowers are slightly _zygomorphic_, and borne in unipared scorpioid cymes. ~_Scopolia_ (pyxidium); _Fabiana_ (Heather-like shrub); _Petunia_ (slightly zygomorphic flower; funnel-shaped corolla); _Nierembergia_; _Brunfelsia_ (almost a drupe); _Franciscea_; _Browallia_.~--Among those with capsular fruits are found the most anomalous forms, which by their zygomorphic flowers and often didynamous stamens present the transition to the Scrophulariaceæ: _Salpiglossis_; _Schizanthus_ (lobed petals; 2 perfect, and 3 rudimentary stamens).

FIG. 559.--Flower (1/1).

FIG. 560.--Stamen, ejecting pollen.

FIG. 561.--Longitudinal section of seed.]

=B.= FRUIT A BERRY. _Solanum_ (Nightshade); rotate corolla (Fig. 559). The stamens have short filaments, the anthers stand erect, close together round the style, like a cone in the centre of the flower, and open by pores at the apex (Fig. 560). ~_S. tuberosum_ (the Potato-plant); the Potato-tuber is a swollen, underground stem; the “eyes” are buds, situated in the axils of its scale-like, quickly-perishing leaves.~--_Lycopersicum_ resembles _Solanum_ in the flower, but the united anthers open by longitudinal clefts and have an apical appendage. The cultivated species, _L. esculentum_ (Tomato), has often a higher number than 5 in the flower, and in the fruit several loculi of unequal size.--_Physalis_ (Winter Cherry); the calyx ultimately swells out in the form of a bladder, becomes coloured, and loosely envelopes the spherical berry.--_Capsicum_ (Guinea Pepper-plant); some species have very large, irregular, rather dry (red, yellow, black) berries, which are unilocular in the upper part.--_Lycium_ (false Tea-plant); the corolla is salver- or funnel-shaped; shrubs; often thorny.--_Atropa_ (_A. belladonna_, Deadly Nightshade, Fig. 555); corolla campanulate; the calyx projects beneath the spherical, black berry. The flowers are borne singly.--_Mandragora_; (Mandrake); _Nicandra_ (ovary often 5-locular).--~A small tropical group: CESTREÆ (_Cestrum_, _Habrothamnus_, etc.) has an almost _straight_ embryo, which may also be found _e.g_. in species of _Nicotiana_. Related to the Scrophulariaceæ.~

About 1,500 species; the majority within the Tropics, outside
these limits especially in America. _Solanum nigrum_ is a common
weed.--_The Potato-plant_ (_Solanum tuberosum_), from Peru
and Chili, was introduced into Europe in 1584 by Sir Walter
Raleigh. (Potatoes = Batatos). The fruits of several serve as
_condiments_: Chilies or Pod-pepper (_Capsicum annuum_ and
_longum_), and the Cayenne-pepper (_C. baccatum_ and others),
whose fruits also are officinal, were brought to Europe from S.
America by Columbus, and are commonly cultivated in Tropical
America; _Lycopersicum esculentum_ (Tomato) and others from
Peru; _Solanum ovigerum_ (Egg-plant); _Solanum melongena_,
etc. _Poisonous_, _acrid_, _narcotic_ properties (alkaloids,
etc., solanine, nicotine, atropine, hyoscyamine) are found in
many: _Atropa belladonna_ (from S. Europe; the roots and leaves
are officinal); _Solanum dulcamara_ (Bitter-sweet; formerly
officinal), _S. toxicarium_ (Guiana); _Datura stramonium_ from
Asia (leaves and seeds officinal), _D. sanguinea_, _metel_,
_tatula_, and others; _Hyoscyamus_ (officinal: the leaves
and seeds of _H. niger_); _Nicotiana tabacum_ (Virginian
tobacco, officinal: the leaves), _N. rustica_ and others from
Trop. America (_Tobacco_ was introduced into Europe in 1560);
_Cestrum_-species. _Duboisia myoporoides_ (Australia); the
leaves contain _hyoscyamine_ and are used in medicine. A number
of species of these genera are ornamental plants.

Order 2. =Nolanaceæ.= These most resemble the Convolvulaceæ
in the corolla, but the Solanaceæ in their branching, and
leaf-arrangement (in pairs, etc.). The diagram is the same as
in _Nicandra_ with 5 carpels, but the fruits of this order
most frequently form, by invaginations in various directions,
an ovary (with 1 style) consisting of numerous and irregularly
grouped, 1-ovuled cells; the fruit is a schizocarp with many
1-seeded fruitlets.--_Nolana_ (Western S. America): a few are
ornamental plants.

Order 3. =Scrophulariaceæ.= The flower is hypogynous, ☿, _zygomorphic_, with the usual type: S5, P5, A5, and G2, the latter placed _in the median plane_; some genera have all 5 stamens developed (Fig. 562 _A_), but most frequently the posterior one is suppressed and the flower becomes _didynamous_ (Fig. 562 _B_). The fruit, as in the capsular-fruited Solanaceæ, is a bilocular, 2-valved _capsule_, with a _thick, axile placenta_, and most often septicidal dehiscence (Fig. 563 _C_). The _numerous seeds_ are not reniform as in many Solanaceæ, and have a _straight, or only slightly curved embryo_, with abundant endosperm (Fig. 563 _D_).--The majority are herbs; some are arborescent; the leaves are opposite or scattered, but stipules are wanting as in the whole family.

The Scrophulariaceæ are closely allied to the Solanaceæ, and
there is, properly speaking, no characteristic feature which
absolutely separates them. The somewhat irregular corolla, with
five stamens of unequal length in _Verbascum_, is also found
in _Hyoscyamus_; curved and straight embryos are found in both
orders. The activation of the corolla in the Scrophulariaceæ is
_simple imbricate_, in the Solanaceæ most frequently _folded
imbricate_ (in _Atropa_ and those allied to it, imbricate
without folding). The genera (about 164) are distinguished
according to the form of the corolla, number of stamens,
inflorescence, arrangement of the leaves, etc. _Verbascum_
belongs to the most primitive 5-stamened forms, and from it
proceed a long series down to _Veronica_, with only two stamens
and most frequently the posterior sepal suppressed.

=1.= ANTIRRHINEÆ, SNAPDRAGON GROUP. This has most frequently a descending æstivation of the petals (the posterior petals are outside the lateral ones, which again enclose the anterior; Fig. 562 _A_, _B_). The plants belonging to this group are not parasites.

=a.= =5-stamened.=--_Verbascum_ (Mullein, Fig. 563 _A_) has a slightly irregular, rotate corolla; five stamens (frequently covered with woolly hairs), of which the two anterior ones are the longer and differ often also in other respects. ~The inflorescences are racemose, often with several series of accessory dichasia in the axil of each primary floral-leaf. The leaves are scattered and, together with the stems, are often covered with a grey felt of branched hairs.~

=b.= =4-stamened, didynamous= (Fig. 564).--_Scrophularia_ (Fig-wort, Fig. 565) has cymose inflorescences in a panicle; the corolla (Fig. 565) is urceolate, short two-lipped; the posterior stamens are present as a scale below the upper lip of the corolla (Fig 565 _s_). ~_S. nodosa_ has a tuberous rhizome.--_Pentstemon_; the posterior stamen is barren and very long.~--_Antirrhinum_ (Snapdragon). The corolla (Fig. 564) is personate, _i.e._ bilabiate, but with the under lip arched to such an extent that it meets the upper lip, closes the corolla throat, and entirely conceals the stamens and style; the corolla-tube is produced into a short pouch at the base on the anterior side. The capsule is oblique and opens by 2–3 pores, formed by small, dentate valves. In _Linaria_ (Toad-flax) the pouch is produced into a spur. Sometimes there are traces of the posterior stamens. The capsule opens by large pores (one for each loculus), produced by large, many-partite valves. _L. vulgaris_ reproduces by suckers.--_Digitalis_ (Foxglove, Fig. 566) has long racemes with drooping flowers; the posterior sepal is small (a step towards complete suppression, as in _Veronica_); the corolla is obliquely campanulate, and generally nearly 4-lobed, the two posterior petals coalescing.--_Alonsoa_; _Nemesia_; _Chelone_; _Herpestis_; _Mimulus_; _Torenia_; _Vandellia_; _Limosella_ (_L. aquatica_, Mud-wort, native); _Scoparia_; _Capraria_; _Erinus_ (found on the Roman Camp at Chesters, Northumberland, and supposed to have been introduced from Spain by the Roman soldiers); _Celsia_ (near _Verbascum_); _Maurandia_; _Lophospermum_; _Rhodochiton_; _Collinsia_; _Nycterinia_, etc.

=c.= =2-stamened.=--_Gratiola_ (Water-hyssop). 5-partite calyx. The upper lip of the corolla is undivided or slightly bifid; the two anterior stamens are either entirely absent or are reduced to staminodes (a transition to _Veronica_).--_Veronica_ (Speedwell), most frequently 4-partite calyx; 4-lobed, rotate, zygomorphic corolla with 2 perfect stamens and no trace of the others (Figs. 567, 562 _c_); capsule with loculicidal dehiscence. _Calceolaria_; the corolla has two slipper-like lips.

=2.= RHINANTHEÆ, YELLOW-RATTLE GROUP. Herbs, all of which (with the exception of _Lathræa_) are annual _parasites_ with green foliage-leaves. They attach themselves by haustoria to the roots of other plants and draw nourishment from them. The majority turn black when dried. Racemose inflorescences. In many the calyx is 4-partite, the posterior sepal being absent, or very small. The corolla is distinctly bilabiate (Fig. 568), with _most frequently ascending æstiration_; in the majority it does not become detached at the base, but by means of a ring-like cut some distance up the tube; 4 didynamous stamens; pollen-grains dry, easily falling out; the anthers are often furnished at the base with bristles or hairs (Fig. 568) which play a part in the pollination, the probosces of the insects, being forcibly pushed against them, agitate the anthers and shake out the pollen-grains. Capsule with loculicidal dehiscence.--_Euphrasia_ (Eye-bright), _Melampyrum_ (Cow-wheat), _Rhinanthus_ (Yellow-rattle), _Odontites_ (Bartsia), _Pedicularis_ (Louse-wort), and _Lathrœa_ (Tooth-wort) all have native species. The last named is pale yellow, or reddish (without chlorophyll); ~it is a parasite on the roots of the Hazel, Beech and other shrubs, having an aerial stem, and an underground, perennial rhizome, covered with opposite, scale-like, more or less fleshy leaves with a number of internal glandular, labyrinthine cavities. The inflorescence is a unilateral raceme. It approaches _Gesneriaceæ_ in having a _unilocular_ ovary with two parietal placentæ.~

The mechanical contrivances for POLLINATION are so numerous
that no general principle can be laid down. Personate flowers,
like those of _Antirrhinum_ are only accessible to strong
insects, such as humble-bees, which can force themselves
between the two lips, and so become dusted with pollen on
the back. In _Euphrasia_ and other _Rhinantheæ_ the insects
become covered with smooth, powdery pollen when they shake
the anther-apparatus in touching the hairs and bristles
mentioned above. _Scrophularia nodosa_ is protogynous (Fig.
565). _Digitalis purpurea_, however, is protandrous. _Mimulus
luteus_ and some others have sensitive stigmatic lobes, which
shut up on being touched. The _Veronica_-species constitute
a series, from large-flowered down to small-flowered forms,
and parallel with them are found various gradations from
insect-to self-pollination. In some (as _Euphrasia officinalis_,
_Rhinanthus crista galli_) there are two kinds of flowers:
large, which are pollinated by insects, and small, which are
self-pollinated (Fig. 568). _Lathræa squamaria_ (Tooth-wort)
is a protogynous spring-flowering plant, largely visited by
humble-bees. Others have cleistogamic flowers. _Nycterinia
capensis_ opens its flowers at night.

2,000 species; chiefly from the Temp. OFFICINAL: _Digitalis
purpurea_ (the leaves; Europe), a poisonous plant. _Verbascum
thapsus_ and _thapsiforme_, _Veronica officinalis_ (“Herba V.”),
_Gratiola officinalis_ (“Herba”) have medicinal uses. The whole
of the Scrophulariaceæ are more or less suspicious, if not
actually poisonous, and none serve as food. Many are ORNAMENTAL
PLANTS: _Mimulus luteus_ (N. America), _Paulownia imperialis_
(the only species; in Japan; a tree), _Antirrhinum vulgare_ (S.
Eur.), _Linaria_, _Pentstemon_, _Veronica_, _Calceolaria_ (Peru,
Chili, etc.).

Order 4. =Utriculariaceæ.= To this order belong only perennial, _insectivorous_, _aquatic_, and _marsh-plants_ (200 species) with a more or less characteristic appearance. They differ from the Scrophulariaceæ, especially in having =2= stamens (the anterior) and a _unilocular ovary_, with _free, central placenta_ (like that of the Primulaceæ). For the rest the flower is distinctly bilabiate, both in the calyx and corolla. Two-valved capsule; no endosperm.

_Pinguicula_ (Butter-wort) has a rosette of leaves close to the ground; these are sticky, covered with glandular hairs, and roll round any small insects which may be caught upon them; flowers solitary, terminal on a long scape; calyx, 5-partite; corolla with spur. The embryo germinates with 1 cotyledon.--_Utricularia_ (Bladder-wort). Our native species are floating, _without roots_, with hair-like, divided leaves, studded with peculiar bladders (in the Tropics there are terrestrial species, with ordinary foliage). The bladders (Fig. 569) have an aperture, closed by a valve opening inwards, so that small aquatic animals are allowed to enter, but are not able to escape; they are thus entrapped in the bladders, and are probably used as food. Calyx bipartite; corolla personate with spur.

The _embryo_ of _Utricularia_ is very imperfect, scarcely
more than a spherical, cellular mass, with a few slight
leaf-rudiments. On the germination of _U. vulgaris_, several
bristle-like leaves develop into a compact rosette; the stem
then develops, and also the finely-divided, bladder-bearing
leaves. A primary root is not developed. The stems branch
copiously and in a very peculiar manner. The growing-point of
the stem is rolled spirally.--The stigmatic lobes are sensitive
and close on being touched; self-pollination often takes place,
however, in _Pinguicula_.

Order 5. =Gesneriaceæ.= The flower in this order may be both
_epigynous_ (_Gesnerieæ_) and _hypogynous_ (_Cyrtandreæ_),
but otherwise is nearly the same as in Scrophulariaceæ,
only that _the ovary is unilocular_, with 2 _parietal_,
often bifid, _placentæ_. Of the 5 stamens the posterior is
rudimentary, or (more rarely) entirely wanting, and the others
are didynamous (Cyrtandreæ have often only 2 stamens); their
anthers are generally glued into a quadrangular mass. The
majority are herbs with juicy stems, opposite, verticillate
or scattered leaves without stipules, often, like the stems,
thick and juicy, soft-haired or glabrous. The corollas are
often highly-coloured (scarlet, red-yellow, etc., and spotted
internally), large and magnificent, so that many species are
ornamental plants. GESNERIEÆ (often epigynous) have endosperm;
S. Am.--CYRTANDREÆ, hypogynous, without endosperm; Asia, S.
Africa.--_Streptocarpus_, neither the primary root nor primary
shoot attains development; one of the cotyledons dies, while the
other grows and becomes a very large foliage-leaf, from which
spring adventitious roots and adventitious inflorescences.

500 species. _Gloxinia_, _Achimenes_, _Gesneria_, _Alloplectus_,
_Tydæa_, _Columnea_, _Nægelia_, _Æschynanthus_, and others,
especially in the forests of tropical America. Some are
epiphytes on trees, others prefer the leaf-mould of the
forest and crevices of cliffs. Several genera have peculiar,
catkin-like, underground shoots, with scale-like compact leaves;
others have tubers.

_Orobanche_ (Broom-rape) is allied to this order as a
_parasitic_ form. It is a parasite on the roots of other
plants, not like _Lathræa_ by means of thin rootbranches with
haustoria, but growing with the base of its stem in close
contact with its host, and probably even often protruding a kind
of thallus into it, in a manner similar to the Loranthaceæ. Its
aerial shoots are not entirely destitute of chlorophyll, but
are not green; they only bear scale-leaves and terminate in a
raceme or spike-like inflorescence.--Some _Orobanche_-species
are detrimental to various cultivated plants (Hemp, Lucerne,
Tobacco, etc.). The flowers are strongly zygomorphic; the
posterior sepal is often wanting, and the anterior are united
to the two lateral ones. Ovary unilocular, as in Gesneraceæ,
with 2 or 4 parietal placentæ.--The exceedingly small seeds have
a very rudimentary embryo, formed of an ellipsoidal, cellular
mass, without indication of cotyledons or other organs.--About
100 species; especially in the Mediterranean region.

Order 6. =Bignoniaceæ.= 500 species; nearly all trees and
shrubs, and to a great extent lianes, climbing by tendrils
(modified leaves), which are sometimes terminated by a
special clasping apparatus. These lianes have, as a rule, an
_anomalous stem structure_, the wood being either divided
into four wedges at right angles to each other, separated
by four grooves filled with secondary wood-parenchyma, or a
greater number of wedges occur, by the cambium ceasing to
form wood in several places. The leaves are most frequently
opposite and compound; the flowers in the main are similar
to the didynamous Scrophulariaceæ, and especially resemble
those of _Digitalis purpurea_; they are bilabiate, large,
and beautiful, campanulate or trumpet-shaped, many of the
prettiest ornamental plants in the Tropics belonging to this
order. The fruit is most frequently a large, woody, 2-valved,
siliqua-like, septifragal capsule, whose valves separate from
the flat and broad partition-wall, which bears the large,
generally winged seeds: _Tecoma_; _Bignonia_.--In gardens:
_Catalpa syringæfolia_ (Trumpet-wood); _Tecoma radicans_
(from S. Am.).--“Palisander”-wood is from _Jacaranda_ (S.
Am.).--_Eccremocarpus_ (N. Am.) forms, by its unilocular
capsule, a transition to the Gesneriaceæ (_E. scaber_;
herbaceous).

_Crescentia_ is allied to this order; _C. cujete_ (Calabash) is
its best known species. The fruit (unilocular with 2 parietal
placentæ) is a very large, spherical or ellipsoidal berry, with
a firm, finally woody outer layer. After the removal of the
juicy interior, these are commonly used as drinking vessels in
Tropical America.

Order 7. =Pedaliaceæ.= _Sesamum_ (_orientale_ and _indicum_);
very important oil-plants, which from olden times have been
cultivated in tropical Asia and Africa for food and as medicinal
plants, and are now cultivated in America also. The seeds are
used as a raw material in the manufacture of soap in Europe.--To
this order also belong _Martynia_ and _Craniolaria_, which have
a long horned capsule and sensitive stigmas.--46 species.

Order 8. =Acanthaceæ.= 1,500 species; mostly erect, slender,
branched herbs or shrubs, rarely arborescent, especially in
S. Am. and Ind. The branches frequently have swollen nodes;
the leaves are _opposite_, penninerved, undivided, more or
less lanceolate or elliptical, and generally leave a distinct
scar when they fall off. Stipules are wanting. The flowers are
solitary or in dichasia, which are arranged in 4-rowed spikes
or racemes, each flower with its subtending bract, which may be
brightly coloured, and most frequently also with two bracteoles.
With regard to the corolla (which is often labiate, in any
case irregular, and frequently prettily coloured), the 2 or
4 didynamous stamens (of whose anthers one half is inserted
lower than the other, or suppressed) and the gynœceum, the
Acanthaceæ are true Personatæ, approaching most nearly to the
Scrophulariaceæ: they differ from the other orders especially in
the _fruit_, which is a bilocular, 2-valved, often elastically
dehiscing capsule, which never has more than 2 rows, and in some
only 2 seeds in each loculus, the seeds being often compressed
and borne on _strong_, _curved_ or _hook-like funicles_
(_retinacula_) which persist after dehiscence. _Embryo curved
without endosperm_; radicle pointed downwards.--Cleistogamic
flowers are found in several species. Cystoliths are common.

The following grow wild in Europe: _Acanthus_ (_spinosus_
and _mollis_, whose pinnatifid leaves served as models for
the capitals of the Corinthian columns). The posterior sepal
is the largest of all the leaves of the flower, and covers
the other parts like a helmet; the 2 anterior sepals are
united, and the two lateral ones are small and greenish; the
corolla has no upper-lip, but only a 3-lobed under-lip. The
anthers are bilocular; the filaments ultimately become very
firm.--_Justicia_, _Eranthemum_, _Goldfussia_, _Thunbergia_ (a
twiner), _Ruellia_, _Dicliptera_, etc.--Ornamental plants in
conservatories.

Order 9. =Plantaginaceæ= (=Plantains=). The flowers (Figs. 570, 571) are regular, ☿, hypogynous, with a =4=-partite, persistent calyx, a gamopetalous, _scarious_ corolla with =4= projecting lobes, =4= stamens, incurved in the bud, later on projecting considerably, about equal in length, and a bilocular ovary with _one_ long, filamentous, _undivided_, _feathery_, papillose style (see Fig. 571). The ovary is most frequently bilocular with 1–few ovules in each loculus. An hypogynous disc is wanting. The fruit is a _pyxidium_ with 1–few peltate seeds attached in each loculus (_Littorella_ is in several respects an exception). All species are herbs, the majority with leaf-rosettes near the ground, and the flowers in spikes or capitula.

The labiate-like flowers are in this case entirely concealed
under a regular, apparently 4-merous exterior. The structure of
the flower, however, is the same as in the _Scrophulariaceæ_,
only the reduction, which is found in _Veronica_ (compare Figs.
562 _C_, 567 with 570, 571), is also present in this instance
and the lobes are also more equally developed; the posterior
petal corresponds to the bilobed upper-lip; the posterior stamen
and the posterior sepal also are entirely wanting. In the
development of the flower there is no trace of posterior sepal
or stamen, and the posterior petal arises from one primordium,
but the two anterior sepals arise before the lateral ones. The
position of sepals and petals does not agree with that of a
true 4-merous flower, which is represented in Fig. 361 _E._ The
bracteoles are always suppressed in _Plantago_.

_Plantago_ (Plantain, Rib-grass). The foliage-leaves are most frequently scattered, entire, with curved veins, arranged in a rosette close to the ground on an unlimited rhizome; the spike-like inflorescence is borne on a long scape; in some (_P. psyllium_) the leaves are opposite on a stem with well-developed internodes, and the inflorescences are borne in their axils. The order also presents a transition from insect-pollinated to wind-pollinated flowers. ~The flowers are protogynous, wind-pollinated in _P. major_ and _P. lanceolata_, partly also in the other species, but insect pollination also occurs, and _P. media_ has three kinds of flowers, some of which are adapted for wind-pollination (Fig. 571), others, with short filaments, for insects.~ _Littorella lacustris_ (Shore-weed) is the most reduced of the Plantaginaceæ: an aquatic plant with rosettes of round, awl-like leaves and diclinous (monœcious) flowers. ~In the axils of the foliage-leaves is a very short 3-flowered spike, formed by 2 sessile ♀-flowers, and above them a long-stalked ♂-flower; all the flowers are lateral, the terminal one being absent, as in _Plantago_. The ♂-flower is essentially the same as in _Plantago_, but the ♀-flower has a scarious corolla, with a narrow, 3–4-dentate mouth, which closes tightly round the nut-like fruit.~

FIG. 570.--Diagram of _Plantago media_.

FIG. 571.--Two different forms of the flower (magnified):
1, chiefly adapted for pollination by wind; 2, for
insect-pollination. _a_ The stigma; _b_ the calyx; _k_ the
corolla.]

The genus _Plantago_ constitutes nearly the entire
order (200 species). Some are widely distributed weeds
(_e.g._ _P. major_, “The white man’s footstep”). In
_P. psyllium_ (S. Eur.) the integument of the seeds is
mucilaginous, and swells considerably in water.

Family 31. =Nuculiferæ.=

The flowers are _hypogynous_ and _zygomorphic_ (in _Boraginaceæ_ and _Cordiaceæ_, however, they are regular, except _Echium_ and _Anchusa arvensis_). The calyx is gamosepalous, the corolla _bilabiate_ (except in the two orders mentioned), mostly after 2/3, _i.e._ divided into a 2-leaved posterior portion, and a 3-leaved anterior portion. The æstivation of the corolla is nearly always descending.--In _Boraginaceæ_ and _Cordiaceæ_ there are 5 stamens of equal length; in the other orders 4 didynamous ones, or only 2 fertile; the posterior stamen is sometimes developed as a staminode, sometimes fertile (in _Stilbaceæ_). The ovary is formed of 2 median carpels (except some _Verbenaceæ_), with (1-) =2= ovules on each carpel; in the majority of the orders it is, however, divided by a false partition-wall between the dorsal and ventral sutures, into =4= _loculi_, each of which is often raised independently, causing the style to be situated in the depression between the four lobes (“gynobasic” style, Figs. 572, 573, 575, 579). The fruit in these orders most frequently becomes a _4-partite schizocarp_ with _nut-like fruitlets_. The other orders have a 1(-2)-locular ovary.--The leaves are _simple, without stipules_.

The family is related to (and proceeds from) the _Tubifloræ_,
especially _Convolvulaceæ_, which has an almost similar
construction of the ovary. It is doubtful whether the
_Cordiaceæ_ and _Boraginaceæ_ should be classed with the others.

The orders are: 1, Cordiaceæ; 2. Boraginaceæ; 3, Verbenaceæ; 4,
Labiatæ; 5, Selaginaceæ; 6. Globulariaceæ; 7, Stilbaceæ.

Order 1. =Cordiaceæ= unites Convolvulaceæ and Boraginaceæ.
Tree-like plants with 5-(4–10) merous flowers, doubly bifid
style, and drupe with 4 or less loculi. No endosperm; cotyledons
folded.--185 species; tropical.

Order 2. =Boraginaceæ.= The vegetative parts are very characteristic: _herbs_ with _cylindrical_ stems and _scattered_, undivided, nearly always sessile, entire leaves, without stipules, and generally, together with the other green portions of the plant, covered with stiff hairs, consequently rough and often even stinging (hence the other name for the order _Asperifoliæ_). The inflorescences are _unipared scorpioid cymes_ with the branches coiled spirally (“helicoid,” Fig. 573) before the flowers open. The flower is perfect, _regular_ (obliquely zygomorphic in _Echium_ and _Anchusa arvensis_), hypogynous, gamopetalous: S5, P5 (often with ligular outgrowths), A5, G2, but each of the two loculi of the ovary becomes divided by a false partition-wall into two, each of which contains one _pendulous_ anatropous ovule with the micropyle turned upwards; the four loculi arch upwards, so that the ovary becomes 4-lobed, and the style is then, as in the _Borageæ_, placed _at the base_ (“gynobasic”) between the four projections (Figs. 572, 573). The fruit is a _4-partite schizocarp_ with four nut-like fruitlets (Fig. 572).--_Endosperm is wanting_ (except in _Heliotropium_); the radicle is turned _upwards_.