The diagram of the flower (Figs. 465–467) is the same as in the
Gruinales, namely S, P, A2 and G in whorls of 5 (less frequently 3, 4,
6, 8), and the same modifications also occur with the suppression of
the petal-stamens, etc. But a _ring_ or sometimes _cup-like glandular
structure_ (_disc_) is found _between_ the andrœcium and the gynœceum
(Figs. 465, 466). The flowers similarly are regular, _hypogynous_, ☿
and polypetalous, though exceptions are found to all these characters:
thus, for example, united sepals and petals frequently occur, and,
in some orders, unisexual flowers by the suppression of one sex. In
most cases the flowers are small, greenish-yellow, and arranged in
paniculate inflorescences. The carpels (most frequently 5) are free in
a few, but generally united into a multilocular gynœceum; rarely more
than 1 or 2 ovules in each loculus. The gynœceum in the Anacardiaceæ
is so reduced that it has only 1 fertile loculus with 1 ovule.--The
_ovules are epitropous_, _i.e._ anatropous with outward-turned raphe
(except the Anacardiaceæ).--The majority of the species are trees
and shrubs with scattered, often _compound (pinnate) leaves_ without
stipules, and as in addition they frequently contain _aromatic,
especially turpentine-like substances_, they assume a certain
resemblance to the Walnut trees, and were formerly classed with them
mainly on this account. In a series of genera the volatile, scented
oils are found in special glands in the bark of the branches and in the
leaves, in the latter case appearing as _pellucid dots_. This family
includes several orders which are somewhat difficult to distinguish
from each other.
Order 1. =Connaraceæ.= This order forms the connecting link
between Terebinthinæ and Rosifloræ (_Spiræa_) as well as
Leguminosæ, with which they are sometimes classed. The flowers
have 5 5-merous whorls; 2 ovules in each loculus; micropyle
turned upwards. Fruit a _follicle_, rarely a collection
of follicles. Seed with aril. Shrubs with scattered (most
frequently pinnate) leaves, without stipules. 170 species.
Tropical.
Order 2. =Meliaceæ.= Trees and shrubs with scattered, often
pinnate leaves without pellucid dots and exstipulate; the
leaflets are nearly always entire. Flowers small in paniculate
inflorescences. Calyx and corolla 4–5-merous; 2 whorls of
stamens; 3–5 carpels in the gynœceum. A very characteristic
feature is the union of the filaments into a tube, on the
edge of which stipule-like teeth are often found. There are
most frequently 2 ovules in the loculi; fruit a capsule with
many winged seeds in _Swietenia_ (Mahogany tree; Trop. Am.),
_Cedrela_, etc.; berries in others. The wood of _Cedrela_ is
used for making cigar boxes. 550 species; tropical.
Order 3. =Rutaceæ.= Leaves glandular with pellucid dots. The type
is the same as that of the family. Flowers 4–5-merous. The ovary is
most frequently 4–5-grooved. Disc well pronounced, often appearing as
a “gynophore.” The majority are shrubs with alternate or opposite,
compound, more rarely simple, leaves.
=A.= The ovary is deeply 2–5-cleft with basal styles which are more or
less united; the carpels in some genera are entirely free (groups 1,
2). The fruit is capsular and most frequently dehisces like follicles
along the ventral suture or septicidally, so that a horn-like internal
layer (endocarp) separates elastically from the external layer.
=1.= ZANTHOXYLEÆ. _Zanthoxylum_; _Choisya_; _Evodia_.
=2.= BORONIEÆ. Australia.--_Correa._
=3.= DIOSMEÆ. Heather-like shrubs; Africa.--_Diosma_,
_Coleonema_, _Empleurum_ and _Barosma_. OFFICINAL: _Barosma
crenulata_ and _betulina_, “broad Buchu leaves” (_B.
serratifolia_ and _Empleurum serrulatum_, “narrow Buchu-leaves”).
[Illustration: FIG. 465.--_Ruta._ Flower (mag.).]
[Illustration: FIG. 466.--_Ruta._ Longitudinal section of flower.]
[Illustration: FIG. 467.--_Ruta._ Floral diagram.]
=4.= RUTEÆ. _Ruta_ (Figs. 465–467) _graveolens_ is an herbaceous,
glaucous, strongly smelling plant with bipinnate leaves and yellow
flowers; the terminal flower is 5-merous, the others 4-merous (S.
Eur.).--_Dictamnus_; zygomorphic flower. ~The individual carpels of the
fruit separate from each other, and dehisce like follicles, upon which
the internal layer is detached elastically and springs out, carrying
the seeds with it. Several species are ornamental plants.~
=5.= CUSPARIEÆ. American. Flowers often zygomorphic with
gamopetalous corolla; stamens 5.--_Ticorea_; _Galipea_ (_G.
officinalis_; S. Am.; “Cortex angosturæ”); _Cusparia_;
_Almeidea_.
=B.= The ovary is entire or only slightly grooved; the style is
terminal, undivided. The fruit is most frequently a drupe or berry.
=6.= TODDALIEÆ. _Ptelea_; winged fruit. The buds are enclosed in
the leaf-sheath. _Skimmia_; _Phellodendron_.
[Illustration: FIGS. 468–470.--_Citrus vulgaris._
FIG. 468.--Branch with compound leaves.
FIG. 469.--Transverse section of fruit.