Order 3. =Ribesiaceæ= (=Currants=). 5-stamened Saxifragaceæ with
epigynous flowers.--Moderately sized shrubs with _scattered_, stalked
and palminerved, and generally palmilobed leaves, with a large
leaf-sheath. The flowers (Figs. 490, 491), most frequently borne in
_racemes_, are regular, _epigynous_, and have often, _above the ovary_,
a cup- or bell-shaped, or tubular prolongation of the receptacle, on
which the sepals, petals and stamens are situated; they have 5 sepals
(often large, coloured), 5 _small_, free petals, only =5= stamens
(opposite the sepals) and a =2=-carpellate gynœceum with a _unilocular_
ovary and 2 _parietal_ placentæ bearing many ovules. The fruit is a
_berry_, whose seeds have a fleshy and juicy outer covering (Fig. 492).
~In some species, for example _Ribes grossularia_, there is found an
unbranched, or a 3–5-branched spine, very closely resembling the spiny
leaves of the _Berberis_, but which, however, are emergences springing
from the base of the petiole. _Ribes_ has two kinds of branches:
long-branches and dwarf-branches, the latter alone bearing the
flowers.~--_Ribes_ (Figs. 490–492). The blades of the leaf are folded
or rolled together in vernation. _R. alpinum_ is diœcious.
75 species; especially from the N. Temp. regions (especially
N. Am.).--The receptacle secretes honey on its inner surface.
The Gooseberry-flower is slightly protandrous, others are
homogamous; insect-and self-pollination are found. The following
are FRUIT BUSHES: _R. nigrum_ (Black Currant), _R. rubrum_
(Red Currant), _R. grossularia_ (Gooseberry), originating in
Northern Europe and Asia. ORNAMENTAL BUSHES: the North American
_R. aureum_ (Golden Currant) and _R. sanguineum_ (Blood-red
Currant), etc.
[Illustration: FIG. 493.--_Deutzia crenata._ Longitudinal section
of flower.]
Order 4. =Hydrangeaceæ.= Shrubs, with simple, opposite leaves,
without stipules; flowers generally epigynous, 4–5-merous (Fig.
493).--_Hydrangea_ (_H. hortensia_, etc.). Shrubs from N. Am. and E.
Asia; corolla often valvate. The inflorescence, as in the case of the
inflorescence of _Viburnum opulus_ (Guelder Rose), has often irregular,
large, but barren flowers at the circumference, whilst the others are
much smaller, regular and ☿; the barren flowers are mostly 4-merous;
in these cases it is the calyx which is large and petaloid, while the
other parts of the flower are more or less suppressed. The branches of
the inflorescence appear to be partially devoid of floral-leaves, since
they are displaced upon the main axis.--_Philadelphus_; racemes (with
terminal flower), sepals 4 (valvate), petals 4 (twisted), stamens many,
and carpels 4 (opposite the petals), forming a 4-locular ovary. The
numerous stamens (20–30) occur by the splitting of the sepal-stamens
and are often therefore placed in distinct bundles. Fruit a capsule.
_Ph. coronaria_ (Syringa, Mock Orange-blossom), from S. Eur., is a
common ornamental shrub, as also is _Deutzia_ (Fig. 493) from N. Am.
and E. Asia. The latter has S5, P5, A5 + 5, G3.--About 70 species.
Order 5 (?). =Pittosporaceæ.= This order has its home especially in
Australia (90 species). The flower has S5, P5, A5 (episepalous), G2
(3–5), most frequently a unilocular ovary with many ovules in 2 rows,
borne on 2 parietal placentæ, or a bilocular ovary. Some have berries,
others capsules. _Pittosporum, Citriobatus, Sollya, Billardiera._
Order 6. =Hamamelidaceæ.= Flowers more or less epigynous, with S4, P0
or 4, 4 fertile sepal-stamens, and 4 barren petal-stamens, bilocular
ovary with 1–2 ovules in each loculus. Fruit a capsule. _Hamamelis_:
one species in Japan and one in N. Am. _Fothergilla._ _Liquidambar_:
monœcious; flowers in capitula or spikes; ♂-flowers without perianth,
stamens indefinite; ♀-flower: slight perianth, 2-locular ovary with
many ovules. OFFICINAL: “Styrax-balsam,” which is obtained by boiling
the bark of _Liq. orientalis_, from Asia Minor. _Liquidambar_ and
_Parrotia_ are found as fossils in the Upper Oligocene; _Hamamelis_
perhaps in the Chalk.
Finally two orders with very reduced flowers are included in this
family.
Order 7. =Platanaceæ.= Trees, with large, scattered, palminerved and
lobed leaves, and ochreate stipules; the buds are concealed in a hollow
at the base of the petiole. The bark falls off in large scales. ♂-and
♀-flowers (monœcious) in crowded, spherical inflorescences which are
placed at wide intervals on a terminal, thin, and pendulous axis. The
flowers have an insignificant calyx and corolla; the ♂-flower has few
stamens; ♀-flower, perigynous, with 4 free carpels, 1 _pendulous_,
_orthotropous_ ovule in each. Fruit a nut; endosperm absent. 5 species;
frequently grown in avenues and parks. _P. occidentalis_ (N. Am.); _P.
orientalis_ (W. Asia.).
Order 8. =Podostemaceæ.= Aquatic plants, especially in swiftly
running water, with somewhat of an Alga-like, Moss-like, or thalloid
appearance; they show themselves in many ways to be adapted to their
mode of life and situations (having a dorsiventral creeping stem, the
flowers sunk in hollows, a formation of haptera upon the roots, and
thalloid assimilating roots and thalloid stems, etc.). Tropical; 100
species.