The flowers belong to the ordinary monocotyledonous type. They are
hermaphrodite, _epigynous_, and have either a petaloid perianth, or
calyx and corolla; they are, however, _zygomorphic_ or _unsymmetrical_,
and of the stamens most frequently only one is _completely developed_,
the others being generally represented by petaloid staminodes. The
ovary has 3 loculi, more rarely it is unilocular with the suppression
of 2 loculi. Endosperm is absent (except _Zingiberaceæ_); but, on the
other hand, there is a _large perisperm_. To this family belong large,
glabrous, especially _perennial herbs_ with rhizomes; leaves large,
distinctly divided into sheath, stalk, and blade, the latter being more
or less elliptical or lanceolate, entire, with pinnate venation, and
always with a very _well-pronounced midrib_, gradually tapering towards
the apex, and giving off numerous branches, which run outwards, towards
the margin, at a larger or smaller angle; these _lateral veins_ are
closely packed, and parallel, but with only weak, connecting branches
between them; the leaves, therefore, are easily torn pinnately (Figs.
314, 317). The leaf-sheaths close tightly round each other and form a
false stem.
This very natural family comprises orders closely connected with each
other, but is not itself nearly allied to any other family. First in
the series stands:--
Order 1. =Musaceæ.= The _petaloid_ perianth is strongly zygomorphic,
the anterior leaf being very large (a kind of “labellum”), the
posterior one small; only the posterior stamen is wanting, or is
rudimentary, the other five are developed, and have quadrilocular
anthers; ovary, 3-locular. Seed with straight embryo in mealy perisperm.
[Illustration: FIG. 314.--Two _Musa_-species.]
The best-known genus is _Musa_, the Banana (Fig. 314). From the
short rhizome arise enormously large, spirally-placed leaves, whose
sheaths envelope one another, and form an apparently aerial stem,
several metres in height. The inflorescence is a terminal _spike_
with floral-leaves placed spirally, and sometimes magnificently
coloured; in the axils of each of these several flowers are situated
in two transverse rows (accessory buds); the lowest flowers in the
inflorescence are ♀, the central ones ☿, the upper ones ♂, so that
fruits are only found in the lower region of the inflorescence, the
remaining portion persisting as a naked axis after the floral-leaves
and flowers have fallen off; the inflorescence terminates in an ovoid
bud formed by the flowers which have not yet opened (Fig. 314, the
left-hand figure). The perianth-leaves are united (except the posterior
one). The fruit (known as a “Banana”) is a _berry_, having the form of
a smooth, short, three-cornered Cucumber (as much as 30 cm. in length);
inside the tough skin is found a farinaceous, aromatic pulp. No seed
is developed in the cultivated species.--~Several _Musa_-species are
cultivated in the Tropics for the sake of the fruit (_M. paradisiaca_,
_M. sapientum_); for the fibrovascular bundles, _M. textilis_ (Manilla
Hemp).--Their home is, no doubt, the Tropics of the Old World; they
were introduced into America before the arrival of Europeans. _Musa
ensete_ has dry, leathery fruits; an ornamental plant.~
In _Musa_ the barren, posterior stamen belongs to the inner
whorl; and also in _Strelitzia_ and _Ravenala_; the latter
may have all 6 stamens developed. In _Heliconia_, on the
contrary, it belongs to the outer whorl; in _Heliconia_ the
perianth-leaves are differently arranged, and there is only
one ovule in each loculus. The three latter genera have dry
fruits and leaves arranged in two rows. In the “Travellers’
Palm” (_Ravenala madagascariensis_) the foliage-leaves form an
enormous fan.--Tropical; about 50 species.
The order may be divided as follows:--1. Museæ: _Musa_, _Ravenala_,
_Strelitzia_ in the Old World. 2. Heliconiæ: _Heliconia_ in the New
World.
[Illustration: FIG. 315.--Diagram of a _Zingiberaceous_ flower
(_Kæmpferia ovalifolia_): _b_ bract; _v_ bracteole; _k_ calyx;
_p^1_, _p^2_, _p^3_ the petals; _sst_, lateral staminodes
(“wings”); _lab_ labellum (formed of two staminodes); _st_ the
fertile stamen; * position of suppressed stamen. The ovary is in
the centre of the diagram.]
Order 2. =Zingiberaceæ.= Perianth most frequently divided into _calyx_
and _corolla_. Calyx gamosepalous. Only 1 _fertile stamen_ (the
posterior, Fig. 315, belonging to the inner whorl) with quadrilocular
anther, which encloses the style in a furrow; the 2 stamens in the
outer whorl are staminodes, the median one (the anterior) is wanting.
The 2 lateral staminodes of the inner whorl form the “labellum” (Fig.
315 _lab_), which usually is the largest segment of the flower, and
is often bilobed. Ovules many. The fruit in some is a leathery,
3-valved capsule, with loculicidal dehiscence; in others it is more or
less berry-like and indehiscent, or irregularly dehiscent. Straight
embryo.--The aerial stem is seldom developed to any extent, and the
inflorescences, which are (compound) spikes or racemes, often with
coloured floral-leaves, spring in some (_e.g. Zingiber officinale_)
directly from the rhizome. The leaves are arranged in two rows.--The
ovary in a few instances (_Globba_ and others) is unilocular, with 3
parietal placentæ.
They are perennial herbs with fleshy and tuberous rhizomes,
which are used as condiments and in medicine on account of their
pungent and aromatic properties and also for starch, dyes, etc.
OFFICINAL: _rhizomes_ of _Zingiber officinale_ (Ginger, unknown
wild, but cultivated generally in the Tropics), of _Curcuma
longa_ (Turmeric, a dye, E. India) and _C. zedoaria_, of _C.
angustifolia_ and others (as E. India Arrowroot), of _Alpinia
officinarum_, China (galangal). “Preserved Ginger” from _Alpinia
galanga_. Similar aromatic materials (volatile oils) are present
also, for example, in _the fruits_; Cardamom fruits and seeds
(from _Elettaria cardamomum_, China, seldom from _E. major_).
315 species; Tropics, preponderating in the Eastern Hemisphere,
India, and especially S. Asia, whence all the aromatic
species originate; they are now commonly cultivated in the
Tropics. Some are ornamental plants in greenhouses, _e.g._
_Hedychium_, _Costus_, etc. _Globba_ (with axillary buds in the
inflorescence, as in _Ficaria_), _Renealmia_, _Kæmpferia_.
[Illustration: FIG. 316.--Flower of _Canna_: _f_ ovary; _pa_
calyx; _pi_ corolla; _l_ labellum; _st_ stamens; _an_ anther; _g_
stigma; α and β staminodes.]
Order 3. =Cannaceæ.= American herbs without aromatic properties.
Flowers asymmetric (Fig. 316). Calyx polysepalous. The stamens are
_petaloid_ (Fig. 316 _st_) and barren with the exception of one (the
posterior), which bears on one of its _edges_ a bilocular anther;
another, which is especially large and coloured, is termed the
_labellum_. The style is compressed and leaf-like, with a small stigma
at the apex. Ovules numerous in the 3 loculi. The capsule is furnished
with warts or soft prickles. _Embryo straight._
_Canna_ (30 species; Trop. Am.). The inflorescence is a terminal
spike with 2-flowered unipared scorpioid cymes in the axils of the
floral-leaves. Ornamental plants: _Canna indica_, etc.
The diagram of the andrœcium of the Cannaceæ and Marantaceæ may be
represented in the following manner (calyx, corolla and gynœceum being
omitted):--