=7.= AURANTIEÆ, ORANGE GROUP. Fruit a berry with a leathery external
layer.--The most typical flower is found for example in _Limonia_:
S5, P5, A5 + 5, G5 (2–5).--_Citrus_ has 4–5–8-merous flowers, a
gamosepalous, dentate calyx, free petals, one whorl of stamens which
are split irregularly into several bundles (Fig. 470). The fruit is a
_multilocular berry_ provided with a thick, tough, outer layer. The
juicy pulp, which fills up the loculi and envelopes the seeds, is
formed from many large-celled, juicy hair-structures which arise on the
inner side of the walls of the loculi and by degrees entirely fill them
up; the dissepiments remain thin, and form the partitions so easily
separating from each other (Fig. 469). The seeds in many instances are
remarkable for containing several embryos. The blade of the leaf is
separated from the frequently winged stalk by a _node_ (and hence is a
compound leaf with only the terminal leaflet developed?) (Fig. 468);
in other genera, as _Triphasia_, there is a fully developed trifoliate
leaf. Thorns are frequently developed.--~The species of this genus,
which is a native of the warmer parts of S. E. Asia, are very hard to
separate. The differences are found in the forms of the fruit, the
leaves and the leaf-stalks, and in the number of stamens. _Citrus
medica_, “Cedrat” (Ind.); _C. limonum_, “Citron,” “Lemon” (introduced
into Italy in the 3rd to 4th century). OFFICINAL: the fruits and
essential oil of Lemon. _C. aurantium_ from E. Asia, the Orange
(introduced into Italy in the 14th century). _C. vulgaris_ (Fig. 468),
Bitter Orange (introduced into Europe at the time of the Crusades);
the unripe Bitter Oranges, and peel of the Bitter Orange is officinal;
it is from the flowers of this species especially that the essence
of Neroli is made. _C. limetta_, _C. bergamia_, Bergamot; essence of
Bergamot is officinal. _C. decumana_, Pomalo, a native of the Islands
of the Pacific. About 780 species; chiefly tropical.~
Order 4. =Burseraceæ.= Fruit a drupe; 1–5 stones. The bark,
as well as the other parts, contain strong aromatic resins
and balsams, and hence several species are used: the Myrrh
tree, _Commiphora_ (_Balsamodendron_) from Arabia and Africa;
OFFICINAL: Myrrha (_Commiphora myrrha_). Mecca-balsam from _C.
opobalsamum_, Arabia; E. Africa. The Incense-tree (_Boswellia_)
from the same parts of the globe and E. India. The incense of
_B. carteri_ is medicinal (Frankincense). The resin (Elemi) of
_Protium_-species is officinal, and is used technically for
varnish (S. Am.). Takamahaka-resin from _Elaphrium_ (S. Am.)
_Protium_ (_Icica_); _Amyris_ (1 carpel). 270 species; tropical.
Order 5. =Zygophyllaceæ.= The majority have opposite, pinnate
leaves with stipules. _Leaves without pellucid dots._ The
filaments have a scale on the inner side. The most important is
_Guaiacum officinale_ (West India), the wood (Lignum Vitæ) of
which is very hard and heavy, this wood and Gum-guaiacum are
officinal. Others have a peculiar repulsive smell and taste: the
Creosote shrub (_Larrea mexicana_) and _Zygophyllum simplex_.
_Tribulus terrester_ is a common weed in S. Europe. _Fagonia._
_Peganum harmala_ (South of Russia) yields a red dye.--110
species; especially in the Tropics; several species in sandy
deserts. _Nitraria._
Order 6. =Simarubaceæ.= This order is distinguished by the
abundance of _bitter_ substances which it contains (Quassine)
especially in the bark and the wood. The wood of _Quassia amara_
(Guiana, Antilles) is officinal; _Picraena excelsa_ yields
Jamaica Quassia; the bark of _Simaruba_, _Simaba_-species
and others is used. _Ailanthus glandulosa_ is a garden plant
(pinnate leaves, winged fruit).--110 species. Tropical.
Order 7. =Ochnaceæ.= Flowers diplostemonous, 5-merous. The
unilocular ovaries, which are individually free, project
considerably into the air around the gynobasic style; 1 ovule
in each loculus; the fruitlets are drupes. Shrubs; leaves
alternate, with stipules. _Ochna_; _Ouratea_.--160 species;
tropical; especially American.
Order 8. =Anacardiaceæ.= The ovary rarely contains more than 1
ovule, even though there be several loculi and several carpels;
in _Anacardium_ all the 10 stamens except one become suppressed.
Resin passages.--_Anacardium._ The most peculiar feature is the
development of the flower-stalk into a fleshy body about the
form and size of a pear (_A. occidentale_ from Trop. Am. and
_A. orientale_ from E. Ind.) which bears the kidney-shaped nut
(the so-called “Cashew-nut”) on its apex. _Mangifera indica_
(the Mango-tree, from E. Ind.) is cultivated in several tropical
countries on account of its delicious drupe. Similarly, species
of _Spondias_ (_S. dulcis_, Pacific Islands, _S. lutea_).
Several species of _Rhus_ are ornamental shrubs in this country,
for instance, _R. typhina_ (N. Am.), _R. cotinus_ (the Wig-tree,
the _barren_ flower-stalks of the panicles being feather-like
and hairy); _R. toxicodendron_ (Poisonous Sumach, from N. Am.)
is poisonous. Chinese galls are produced by the sting of a
leaf-louse (_Aphis chinensis_) on _R. semialata_ (China), and
Japanese wax is from the seeds of _R. succedanea_ (Japan).
Considerable quantities of Sumach (_R. coriaria_) are used in
tanning and as a black dye. OFFICINAL: the mastic resin of
_Pistacia lentiscus_ (the Mastic-tree, from the Mediterranean).
The fruits of _Pistacia vera_ (Syria) are edible; _P.
terebinthus_ and others yield turpentine.--450 species; tropical.
Order 9. =Icacinaceæ.= Flowers 4–5-merous; haplostemonous;
receptacle convex or cup-like surrounding the gynœceum; in
the (single) loculus of the ovary, 2 anatropous, pendulous
ovules.--200 species; tropical.