Chapter II: ACROGYNÆ. The apex of the stem or of certain branches is adapted (5)

=C.= COLCHICEÆ.--_Colchicum_ (Autumn Crocus); perennial herbs, with a long, _funnel-shaped, gamophyllous perianth_, and introrse anthers. The flowers of _C. autumnale_ spring up immediately from the underground stem, which is in reality a _corm_ formed of one internode. ~_Colchicum autumnale_ flowers in autumn without leaves; in spring the radical foliage-leaves appear simultaneously with the fruit. The flower is protogynous, and is pollinated by insects (humble-bees, etc.) which seek the honey secreted by the free part of the stamen a little way down the tube. The length of the tube protects the fruit, and not, as in other cases, the nectary.--_Bulbocodium_ and _Merendera_ have unguiculate perianth-leaves, free, but closing together like a tube.~

175 species; chiefly in North America and South Africa.
_Tofieldia_ is an Arctic plant. The order is rich in pungent,
poisonous alkaloids (veratrin, colchicin, etc.). OFFICINAL;
the seeds of _Colchicum autumnale_ (Europe) and _Schœnocaulon
officinale_ (Mexico), and the rhizome of _Veratrum album_
(mountains of Central Europe).

Order 2. =Liliaceæ (Lilies).= Flowers as in the Colchicaceæ but with _introrse_ anthers; _ovary free, 3-locular, with single style; capsule_ 3-locular with _loculicidal_ dehiscence.--The majority are herbs with _bulbs_; the inflorescence is _terminal_. In many species reproduction takes place by means of bulbils (small bulbs) formed in the axils of the foliage-leaves (_e.g. Lilium bulbiferum_, _lancifolium_, etc., _Gagea lancifolia_, etc.), or in the bracts of the inflorescence (many species of _Allium_); in many species several buds are developed as bulbs in the axils of the bulb-scales themselves (accessory buds arising close together), and in some the formation of buds is common on the leaves.

=A.= TULIPEÆ, TULIP GROUP. Bulbs. The aerial, elongated stem bears the foliage-leaves. Flowers few but generally large, with free perianth-leaves. _Tulipa_; style absent, no honey; flowers generally solitary, erect.--_Fritillaria_ perianth campanulate with a round or oblong nectary at the base of each perianth-leaf.--_Lilium_; perianth widely open, generally turned back with a covered nectary-groove in the centre of each segment. Anthers versatile.--_Lloydia; Erythronium._

=B.= HYACINTHEÆ, HYACINTH GROUP. Bulbs. Leaves radical; aerial stem leafless with raceme or spike. In some the perianth-segments are free, in others united. Honey is produced often in glands or in the septa of the ovary (septal glands).--_Ornithogalum_ has a leafy stem; _Scilla_; _Eucomis_ has a tuft of floral-leaves above the raceme; _Agraphis_; _Hyacinthus_; _Puschkinia_; _Chionodoxa_; _Muscari_; _Veltheimia_; _Urginea_.

=C.= ALLIEÆ, ONION GROUP. Generally bulbs. Leaves radical. Stem leafless with a compound umbellate or capitate inflorescence of unipared helicoid cymes, which before flowering are surrounded by two broad involucral leaves.--~_Allium._ Filaments often petaloid and bidentate; in many species bulbils are found in the inflorescence.--Some species have flat leaves: _A. sativum_, Garlic; _A. porrum_, Leek; _A. ursinum_; others have round, hollow leaves: _A. cepa_, Onion; _A. fistulosum_, Winter Onion; _A. ascalonicum_, Eschalot; _A. schænoprasum_, Chive.~--_Gagea_; honey is secreted at the base of the perianth, no special nectary; inflorescence few-flowered.--_Agapanthus; Triteleia._

=D.= ANTHERICEÆ. Rhizome; raceme; the leaves not fleshy and
thick.--_Anthericum_; _Asphodelus_; _Bulbine_; _Chlorophytum_;
_Bowiea_ has an almost leafless stem with curved, climbing
branches.

=E.= ALOINEÆ, ALOES. Stem generally aerial and tree-like,
bearing on its summit thick, fleshy leaves, often with a thorny
edge (Fig. 306). Raceme branched or unbranched.--_Aloë_;
_Gasteria_; _Yucca_ (has secondary thickening, p. 274).

=F.= HEMEROCALLIDEÆ. _Phormium_, (_Ph. tenax._ New Zealand
Flax); _Funckia_ (_Hosta_); _Hemerocallis_.

At this point the following are best placed: _Aphyllanthes_
(_A. monspeliensis_); _Xanthorrhæa_ (Black-boy); _Xerotes_;
_Lomandra_; _Kingia_; the very membranous, dry perianth of the
last resembles that of the Juncaceæ, and also there are only
1–few ovules in the loculi.

POLLINATION by insects. Honey in some is produced on the
perianth (see Tulipeæ), in others by glands on the carpels (in
the septa and parietal placentæ, septal glands): _Hyacinthus_,
_Allium_, _Anthericum_, _Asphodelus_, _Yucca_, _Funckia_,
_Hemerocallis_, etc. Some _Allium_-species are protandrous.
_Fritillaria_ is visited by bees, _Lilium martagon_ by moths,
_L. bulbiferum_ by butterflies, _Phormium_ (New Zealand) by
honey-birds.

About 1,580 species; rare in cold climates; their home is in
sunny plains with firm, hard soil, and warm or mild climate,
particularly in the Old World (S. Africa; As. Steppes;
Mediterranean); at the commencement of spring the flowers
appear in great profusion, and after the course of a few weeks
disappear; during the hot season their life lies dormant in the
bulb, hidden underground. The woody species are tropical.--The
majority of the _introduced_ Liliaceæ (_Fritillaria imperialis_,
Crown-imperial; _Lilium candidum_; _Tulipa gesneriana_;
Hyacinth; _Muscari_-species; _Scilla_-species; _Ornithogalum
nutans_; _Hemerocallis fulva_ and _flava_; _Asphodelus luteus_
and _albus_) come from the Mediterranean and W. Asia; _Funckia_
from China and Japan; several Lilies from Japan and the
Himalayas; _Agapanthus_ from the Cape; _Allium sativum_ is a
native of the Kerghis-Steppes; _A. cepa_ from Persia (?); _A.
ascalonicum_ is not known wild (according to others a native of
Asia Minor), perhaps a form of _A. cepa_; _A. schænoprasum_ from
the N. temp. region.

Many bulbs have pungent properties; many Onions are used as
culinary plants. The bast fibres of _Phormium tenax_ (New
Zealand Flax) are used technically. Dyes are obtained from the
_Aloe_; gum for varnish from the stem of _Xanthorrhæa hostile_
and _australe_. OFFICINAL; “Aloes,” the dried sap of S. African
species of _Aloe_ (_A. Africana_, _A. ferox_, etc.); the
bulb known as “Squills” from _Urginea_ (_Scilla_) _maritima_
(Mediterranean).

Order 3. =Convallariaceæ.= This order differs from the Liliaceæ in having the _fruit a berry_ (Fig. 308) and _in never being bulbous_; the seeds are less numerous.

=A.= CONVALLARIEÆ, LILY OF THE VALLEY GROUP. Rhizome (Fig. 307) and normal foliage-leaves.--_Polygonatum_: rhizome creeping; aerial shoot leafy, bearing the flowers in racemes in the axils of the foliage-leaves; perianth tubular. _P. multiflorum_ (Solomon’s seal), _P. officinale_, etc.--_Majanthemum_: flower 2-merous; perianth almost polyphyllous, spreading. _Smilacina. Streptopus_ (_S. amplexifolius_; the flowers or inflorescence unite with the entire succeeding internode).--_Convallaria_ (1 species _C. majalis_, Lily of the valley); flowers in terminal racemes; 2 basal foliage-leaves; perianth globose, bell-shaped. _Reineckea carnea_ (Japan, China) in gardens.--_Paris_ (_P. quadrifolia_, Herb-Paris); flowers solitary, terminal, 4-merous, polyphyllous; styles 4, free (approaching the Colchicaceæ; it is also poisonous); a whorl of 4 (-more) 3-nerved, reticulate leaves on each shoot.--Ornamental plants: species of _Trillium_, _Aspidistra elatior_ (Japan).

=B.= ASPARAGEÆ, ASPARAGUS GROUP. Scale-like leaves and green assimilating branches.--_Asparagus_: horizontal rhizome. The aerial shoots are very richly branched; the numerous needle-like bodies upon the plant are _leafless shoots_, which are crowded together in double scorpioid cymes in the axils of the scale-leaves; the two first lateral axes, placed outside to the left and right, generally bear flowers. Polygamous.--~_Ruscus_ (Butcher’s broom) is a S. European _shrub_ with _leaf-like_, ovoid or elliptical shoots (phylloclades) which are borne in the axils of scale-like leaves, and bear flowers on the central line. Diœcious. Stamens 3, united, anthers extrorse. _Semele androgyna_ bears its flowers on the edge of the flat shoot.~

=C.= SMILACEÆ. _Smilax_ (Sarsaparilla) (Fig. 308); _climbing_ shrubs with the leaf-sheath produced into tendrils. The leaves have 3–5 strong nerves proceeding from the base, and are reticulate. Orthotropous or semi-anatropous ovules. Diœcious (Fig. 308 _C_, _E_).

=D.= DRACÆNEÆ. Fruit in some a berry, in others a capsule.
The stem of DRACÆNA, when old, has the appearance of being
dichotomously branched; it has the power of increase in
thickness, and may become enormously thick. The Dragon-tree of
Teneriffe, measured by Humboldt, attained a circumference of
14 m. and a height of 22 m.; the leaves are large, linear or
linear-lanceolate.--_Cordyline_ (East Asia), various species in
gardens and greenhouses (_Yucca_ is closely allied). _Astelia._

POLLINATION. _Paris quadrifolia_ and _Convallaria majalis_
have no honey, and are chiefly visited by pollen-collecting
bees (in the absence of insect visits self-pollination takes
place); _Polygonatum multiflorum_ has honey secreted by septal
glands and protected by the base of the tubular perianth; it
is pollinated by humble-bees, etc. _Asparagus officinalis_ has
small, polygamous, greenish, honey-bearing flowers; the ♂-flower
is almost twice as large as the ♀; both have rudiments of the
opposite sex.

About 555 species; especially from N. America, Europe, and
Central Asia.

OFFICINAL: “Dragons’-blood,” a red resinous juice from the stem
of _Dracæna_ and the roots of some Central American species of
_Smilax_. The tuberous stems of the Eastern Asiatic _Smilax
glabra_ are officinal. The flowers of _Convallaria majalis_
have been lately used as a substitute for _Digitalis_. Pungent,
poisonous properties are possessed by _Paris_. None of the
species are used as food, except the young annual shoots of
_Asparagus officinalis_, a shore-plant which is used as a
vegetable.

Order 4. =Pontederiaceæ.= Flowers generally zygomorphic,
hypogynous, ☿, with handsome, white or violet, petaloid perianth
which forms a tube at its base. The stamens are inserted at
different heights in the perianth-tube, and are reduced to
three (in _Heteranthera_ seldom to one). In some the ovary is
trilocular with ∞ ovules (_Eichhornia_), in others reduced to
one loculus with one ovule (_Pontederia_). Fruit a capsule or
nut. Embryo as long as the abundant, mealy endosperm.--Tropical
water-plants (22 species) with peculiar sympodial branching,
nearly the same as in _Zostera_. Spikes without floral-leaves.
Many intercellular spaces in the stem and leaf.--In greenhouses:
_Eichhornia azurea_, _E. crassipes_ (both from tropical and
sub-tropical S. America); the latter has swollen petioles which
serve as floats and enable it to float freely on the water,
sending down its roots into the mud. _Heteranthera reniformis,
H. zosterifolia. Pontederia cordata._

Order 5. =Amaryllidaceæ (Narcissi).= The flower is _epigynous_, otherwise exactly the same as in the Liliaceæ (6 stamens). The majority, like these, are also _perennial_ herbs with bulbs and scapes. The fruit and the other characters as in the Liliaceæ. The external appearance is, however, very different.

=A.= AMARYLLEÆ have bulbs and the leaves generally arranged in two rows; the flowers are borne singly or in umbel-like inflorescences on lateral scapes, while the main axis of the bulb is unlimited. Beneath the inflorescence is an _involucre_ (Fig. 309).--_Galanthus_, Snowdrop, has a polyphyllous perianth without corona; the three inner perianth-leaves are emarginate and shorter than the outer; the anthers dehisce apically. ~_Leucojum_ differs in having the perianth-leaves equal in length.--_Amaryllis_ has a funnel-shaped perianth, entirely or nearly polyphyllous, but somewhat zygomorphic. _Crinum; Hæmanthus; Clivia._~--_Narcissus_ has a tubular _corona_, a ligular structure arising from the perianth-tube exterior to the outer stamens. ~In _Pancratium_ (Fig. 309) the corona is united with the filaments which appear to spring from its edge. _Eucharis amazonica._~

=B.= HYPOXIDEÆ. The leaves, which are grass-like, dry, folded,
and in some hairy, spring from a rhizome, generally with a
divergence of 1/3. Flowers small, perianth polyphyllous,
persistent, on which account perhaps the Hypoxideæ may be
considered as the least altered type. The chief characteristic
is that the embryo is separated from the hilum. _Hypoxis_;
_Curculigo_ (_C. recurvata_, a favourite ornamental plant; S.E.
Asia).

=C.= ALSTRŒMERIEÆ. (_Alstrœmeria_, _Bomarea_); stems long,
leafy, often climbing.

=D.= VELLOSIEÆ (_Vellosia_, _Barbacenia_); stem woody, usually
dichotomously branched, with terminal, single flowers; it bears
numerous aerial roots which pierce the leaves and surround the
stem. Stamens often (by splitting) 6–18. High table-lands of S.
America and S. Africa.

=E.= AGAVEÆ. Very similar to the Bromeliaceæ both in their
distribution (nearly all American) and in external appearance.
They appear as gigantic bulbous plants with perennial, aerial,
generally short stem, and perennial, large, lanceolate or
linear, stiff, thick, and often thorny leaves, which form a
large rosette; after the course of several (8–20) years the
terminal inflorescence is developed, which is 10–12 m. high,
paniculate, and freely branched. Before the inflorescence
expands, a large quantity of sugar-containing sap is collected
from _A. americana_ by removing the terminal bud; this on
distillation yields “pulque,” the national drink of Mexico.
After flowering the entire shoot dies, but the subterranean
lateral shoots survive and reproduce the plant.--_Agave
americana_, etc.; _Fourcroya_; _Polianthes tuberosa_ (Tuberose;
Central America).

DISTRIBUTION. The 650 species are chiefly natives of S. Africa
and S. America. _Clivia_, _Hæmanthus_, _Amaryllis_ are from the
Cape; _Narcissus_ from S. Europe, whence many species have been
introduced; _Galanthus_ and _Leucojum_ are especially from S.
and Central Europe, and from the Caucasus.

USES, few, except as ornamental plants: _Galanthus nivalis_;
_Leucojum_; _Narcissus pseudonarcissus_, _N. poeticus_, _N.
jonquilla_, _N. tazetta_, etc.; _Amaryllis_, _Alstrœmeria_,
_Eucharis_, _Crinum_, _Vallota_, etc. The vascular bundles of
the various species of _Agave_ (_Agave rigida_, var. _sisalana_,
sisal hemp,) are used for cordage, etc.

Order 6. =Bromeliaceæ.= The flowers are hypogynous, epigynous or semi-epigynous; the perianth is divided into _calyx_ and _corolla_; stamens 6. The fruit is a capsule or berry with many seeds. Endosperm _mealy_, embryo small, at the edge of the endosperm, but not enclosed by it.

Perennial herbs with a very _characteristic appearance_ (Fig. 310); the stem is most often short, thick, and crowned by a _rosette_ of many leaves, which are long, often very narrow, _leathery_, stiff, and with a _spiny_ edge; they are usually channeled, completely closing round each other, with their edges forming a tightly closed hollow, in which generally water is collected (this among other things insulates the inflorescence and thus prevents the access of creeping insects, such as ants). The presence of numerous stellate, water-containing hairs often gives the leaves a grey appearance, and the layers of cells beneath the upper epidermis of the lamina form an “aqueous tissue,” which serves as a protection against the rays of the sun and regulates the evaporation. The stomata are often situated in furrows on the underside of the leaf, and hence cause a striped appearance. They _are all American_ (525 species), especially from S. America, where they live partly as epiphytes _on trees_, partly in the _clefts of rocks_, often on the steepest slopes, to which they firmly attach themselves by aerial roots; some are terrestrial. The stem is seldom tree-like or many metres in height (_Puya_, in Chili; _Hechtia_, in Mexico). _The inflorescence_ is a terminal spike, raceme, or panicle, often with large and brightly-coloured floral-leaves. The flowers are without scent. The seeds, in the species whose fruit is a capsule, are often provided with wings (hairs, expansions, etc).--_Ananassa sativa_, Pine-apple (W. Indies, Central America) is cultivated for the sake of its juicy, aromatic fruits, which coalesce with their fleshy bracts and form a large spike-like fruit-cluster (multiple-fruits,[29] Fig. 311) bearing on its apex a leafy shoot, which may be used as a cutting. Seeds very rarely developed.--_Tillandsia_ (_T. usneoides_ is a filamentous, richly branched, rootless epiphyte hanging in masses from trees; Trop. Am.), _Aechmea_, _Billbergia_, _Pitcairnia_, etc.

USES. The leaves of the Pine-apple, in its native country, are
used for the manufacture of cloth.

Order 7. =Hæmodoraceæ.= 120 species; in all parts of the world
except Europe; perennial, often tomentose and resembling
the Bromeliaceæ, Iridaceæ and Amaryllidaceæ. _Hæmodorum_
(Australia).--To this order belong _Ophiopogon_, _Peliosanthes_,
_Sanseviera_, and others.

Order 8. The =Iridaceæ= have _epigynous_, hermaphrodite flowers with petaloid perianth as in the Amaryllidaceæ, but the _interior whorl of stamens is entirely suppressed_, and the 3 developed _outer_ stamens have _extrorse_ anthers (Fig. 279); there is 1 style with 3 large, generally _more or less leaf-like branches bearing the stigmas_. Ovary and capsule as in the Amaryllidaceæ and Liliaceæ.--Perennial herbs; _bulbs are rarely found_, but horizontal rhizomes, corms, etc., take their place. The leaves are (except _Crocus_) as in the _Iris_, _two-rowed_, _equitant_ and _sword-like_. Flowers or inflorescences terminal.

The _Iris_ (Flag) has a horizontal rhizome. The flowers are borne in the leaf-axils in fan-like inflorescences (rhipidium). The branches of the style are large and _petaloid_; on their under surface may be seen a small projecting shelf (Fig. 312 _a_) having on its upper surface the stigmatic hairs. Beneath the branches of the style are 3 well protected stamens, and immediately outside these the external perianth-leaves. ~The honey is secreted in the perianth-tube, and the insects, endeavouring to obtain it through the narrow passages at the base of the stamens, settle upon the outer perianth-leaves, which are bent backwards and often very hairy along their central line. The insects then rub their backs on the anthers just above them, beneath the branches of the style; they readily deposit the pollen on the stigma of another flower as they enter it, but cannot do so in withdrawing, since the stigma is pushed back, and self-fertilisation is thus avoided. The stylar branches lie close to the outer perianth-leaves, which are just beneath them, or separated by a distance of only 6–10 mm.; the first form of flower is adapted for _Rhingia rostrata_, the latter for bees~.--_Crocus_ has vertical, _tuberous_, underground stems surrounded by the leaf-sheaths (corms), and terminal flowers; the linear leaves _are not equitant_, but have two longitudinal furrows on the under side. The perianth is gamophyllous and funnel-shaped. The stylar branches (stigmas) are fleshy, _rolled together in the shape of a horn_, and split along the edge.--_Gladiolus_ has corms like the _Crocus_; spikes with slightly zygomorphic, almost bilabiate flowers, most frequently turning to one side. Position of the leaves as in the Iris.--~_Diplarrhena_ has 2 fertile and 1 barren stamen; _Hermodactylus_ has a unilocular ovary with 3 parietal placentæ. _Cypella_ and _Tigridia_ have bulbs.~

770 species; chiefly in the countries round the Mediterranean,
and in Africa, especially the Cape (_Gladiolus_, _Ferraria_,
_Moræa_, _Galaxia_, _Sparaxis_, _Antholyza_, _Tritonia_,
_Ixia_, etc.), Australia and Tropical America (_Sisyrinchium_,
_Tigridia_, _Cipura_, _Cypella_, etc). A great number are
ornamental plants: the cultivated _Crocus_-species are from the
South of Europe and Asia; _Gladiolus communis_ from S. Europe;
the other species principally from S. Africa. The native species
of _Iris_ are _I. pseudacorus_ (yellow) and _I. fœtidissima_.

OFFICINAL: the stigmas of _Crocus sativus_ (Oriental, cultivated
in France, Spain, Italy, and Austria), used as a colouring
matter, saffron; the rhizomes of the S. European _Iris
florentina_, _pallida_, and _germanica_ (“Orris-root”).

Order 9. =Dioscoreaceæ.= Perennial herbs with fleshy, often very large _tuberous rhizomes_ (or roots); _twining_ stems; leaves stalked, often arrow- or heart-shaped, lobed, _palminerved_ and _finely reticulate_ as in the Dicotyledons (Fig. 313). The flower is _diclinous_ (most frequently _diœcious_), regular, _epigynous_, _small_, and of a _greenish colour_, but otherwise typical (Pr3 + 3, and A3 + 3, or G3); in most instances 2 ovules are placed one above the other in each loculus. The inflorescence is a _spike_ or _raceme_, sometimes richly branched and paniculate.--The order approaches most nearly to the Amaryllidaceæ.

_Tamus_ (Bryony) has a berry, _Dioscorea_ (Yam) a thin-walled, 3-edged or 3-winged capsule (Fig. 313). Both have subterranean or aerial tubers; the Yam very often also developes tubers in the axils of the foliage-leaves; tuberous roots are said to occur in _D. batatas_. The tubers of many species of Yams (_D. batatas_ from China and Japan, _D. alata_, South Sea Islands and India, _D. bulbifera_) are a very important source of food in the Tropics, especially the first-named.--_Testudinaria_; _Rajania_.--~The tuberous stem of _Tamus communis_ and _Testudinaria elephantipes_, and some species of _Dioscorea_ is formed from one single internode (epicotyl), and the aerial shoots are developed from adventitious buds; in _T. elephantipes_ the stem is aerial, and covered with thick scales of cork, regularly arranged, and separated by grooves.~

Tropical order (167 species); 2 species (_Tamus communis_ and
_Borderea pyrenaica_) in Europe.

Family 6. =Scitamineæ.=

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.

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.

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_.

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):--

CANNACEÆ. MARANTACEÆ.

_w_ _w_ _w_ _w_
_st_ _st_
_w_ _lab_ _wi_ _c_
* *

_w_ The lateral staminodes, “wings;” _st_ fertile stamen; * the
suppressed stamen; _lab_ labellum; _c_ hood; _wi_ inner-wing.

The labellum of the Cannaceæ corresponds with the hood of the
Marantaceæ and not with the labellum of the Zingiberaceæ.

Order 4. =Marantaceæ.= The flower is asymmetrical. Only 1 or 2 of the 3 stamens in the outer whorl are present as staminodes; in the inner whorl 2 are petaloid and of the sixth stamen one-half is developed as a staminode and the other half bears a bilocular anther. One ovule only in each loculus. The style is strongly curved and at first enclosed in one of the staminodes (hood) of the inner whorl; later on it springs elastically forward towards the other staminode (inner-wing) of the same whorl. The stigma is very oblique or 2-lipped. Two of the three loculi of the ovary, in some (_Maranta_, _Thalia_) become small and empty. Embryo _curved_. Leaves in two rows, with sheath, stalk, and blade (Fig. 317); at the base of the last is a _characteristic swelling_ (_articulus_).--~_Phrynium_, _Calathea_, _Stromanthe_, _Ctenanthe_, _Saranthe_, etc. About 150 species; tropical, especially America. The starch of the rhizome of _Maranta arundinacea_ is OFFICINAL, “West Indian Arrowroot.”~

Family 7. =Gynandræ.=

The flowers are hermaphrodite and constructed on the ordinary 3-merous, pentacyclic type with petaloid, _epigynous, strongly zygomorphic_ perianth, and generally _one-stamened_ by the suppression of the other 5 stamens. The family has derived its name from the fact that the stamen is united with the style into a “_stylar column_” (except _Burmanniaceæ_). All are herbs; many grow as epiphytes on other plants.

This family and the Scitamineæ occupy correspondingly high
positions among the Monocotyledons; these two families may
therefore be placed close together, although one cannot be
derived from the other. The first of the two orders is very
small, but the second is very rich in species. The Apostasieæ
are best classed with the Orchidaceæ and have no independent
place.

Order 1. =Burmanniaceæ.= This order forms a transitional link between the Gynandræ and the epigynous Liliifloræ (_Amaryllidaceæ_), in having a 6-leaved perianth, and 6–8 stamens; but some have a labiate perianth (the median perianth-leaf of the _outer_ whorl being very large). The ovary is most frequently unilocular with three parietal placentæ; but in some it is 3-locular with axile placentation. Capsule. Seeds ∞, small, with _endosperm_. The relationship to the Orchidaceæ is shown especially in the very imperfectly developed embryo and in the ovary. Small, tropical herbs (59 species); some are saprophytes.

Order 2. =Orchidaceæ.= The epigynous, petaloid perianth is strongly zygomorphic in having the _posterior_ leaf of the interior whorl, the _lip_ (labellum), differing from all the other leaves in form, size, and colour (except _Apostasieæ_); the position of the labellum is very frequently reversed, being turned _forwards and downwards_ by the twisting of the ovary (Fig. 318 _A_). _Only_ 1 of the stamens--the anterior of the external whorl--is developed and bears an anther (by the twisting of the ovary it is turned posteriorly and upwards); the others are entirely wanting (indicated by * in Fig. 318 _A_) or present as staminodes (Fig. 318 _A_, δ δ) (except _Apostasieæ_, _Cypripedileæ_); the filaments are united with the style to form a column (Fig. 318 _B_), the _stylar-column_[30] (_gynostemium_), and the anther (_a_) is thus placed on its apex and exactly behind or over the stigma (_s_). The anther is 4-locular; the pollen-grains do not separate (except _Apostasieæ_, _Cypripedileæ_) but remain united either in tetrads or in masses, which correspond to a pollen-mother-cell (Fig. 320 _C_, _D_, _E_); or the pollen-grains, formed in each of the two anther-halves, remain united and form one or a few wax-like masses (pollen-masses, pollinia). The 3 carpels form a _unilocular ovary_ with 3 parietal, deeply bifid placentæ (except _Apostasieæ_, _Selenipedilum_). Only the two lateral carpels are prolonged and developed into the stigma (Fig. 318 _B_, _s_), while the one lying in the median line, which is situated just within the anther (Fig. 318 _A_), becomes either rudimentary or developed into the “_rostellum_” (“a small beak”), on which the sticky bodies (_glandulæ_) arise; by aid of these the heavy, connected pollen-masses may be glued to the insects which visit the flower, and pollination is thus secured (in _Apostasieæ_ and _Cypripedileæ_ the 3 carpels each contribute to the formation of the stigma). The fruit is a _capsule_ which most often dehisces _by 6 valves_, 3 of which are broader and bear the placentæ, and 3 alternating with them are narrower and barren (except _Vanilla_). The very numerous and exceedingly small seeds have _no endosperm_, and have a somewhat _spherical embryo without any trace of external organs_. The testa is membranous and loose.

The Orchids are _all perennial herbs_ with diverse habits and varying morphological structure (see the genera); the leaves are scattered, of the usual Liliaceous form, and the inflorescences in all cases are _racemes or spikes_ (sometimes branched), with subtending bracts, but without bracteoles.

The forms which are the least modified are described first.

=1.= APOSTASIEÆ. The perianth-leaves are almost alike and free. The column is straight, with 3 equally-developed stigmas. _Neuwiedia_ has 3 perfect stamens (1 median of the outer whorl, and 2 lateral of the inner whorl); _Apostasia_ has only 2 perfect (inner lateral) and one barren (the median of the outer whorl), which however may be entirely wanting. The 3 _posterior_ stamens are entirely suppressed. The pollen is powdery. The ovary is 3-locular with axile placenta. 7 species (Tropical East India, Australia).

=2.= CYPRIPEDILEÆ.[31] The flower is strongly zygomorphic with a large boat-shaped labellum. There are two perfect stamens belonging to the _inner_ whorl, and the median anterior (later on the posterior) stamen of the outer whorl is transformed into a large, barren, shield-shaped body (Fig. 319). _Selenipedilum_ has a 3-locular ovary, but _Cypripedilum_ (Ladies’-slipper) has a unilocular ovary with 3 parietal placentæ--the typical structure for the Orchids. The pollen-grains are _separate_ (not in tetrads) and all the 3 lobes of the stigma are constructed to receive them. This group is therefore, next to the Apostasieæ, the least modified among the Orchids; in all the following groups, one of the lobes of the stigma is differently developed from the others, and there is only one stamen.--Terrestial Orchids.--~The pollination of _C. calceolus_ is effected by the forcible entrance of insects into the boat-shaped labellum (Fig. 319 _p’_) at _i_, and their escape at _ex_ (in 2) where the anthers are situated; in this way the stigmas will first be touched and then the anthers. The pollen-grains are surrounded by a sticky mass in order that they may adhere to the insects.~

=3.= NEOTTIEÆ. The majority are terrestrial Orchids with creeping, sympodial rhizomes; the blades of the leaves are not detached from the stem at joints, and have convolute vernation. The anthers do not drop off, but persist in the withered condition; their _apex_ is brought in contact with the rostellum (acrotonous Orchids). The pollen-grains are united in _tetrads_, which, however, often hang loosely together in pollinia, attached to a sticky part of the rostellum (“adhesive disc”), so that they adhere to the insects, and are by them transferred to the stigmas. _Spiranthes. Listera_; _Neottia_. ~_N. nidus-avis_ (Bird’s-nest) is brown (it has little chlorophyll) in colour, has no foliage-leaves, and lives mainly as a saprophyte; the rhizome is studded with unbranched, fleshy roots which may form buds at their extremities.~--_Vanilla_ climbs by aerial roots. The fruit is fleshy and hardly opens, or does so irregularly.--_Epipactis_, _Cephalanthera_.--_Epipogon_ and _Limodorum_ are saprophytes without chlorophyll.

=4.= OPHRYDEÆ. Anthers 2-locular, not falling off, on a very short column. The anther is united at _its base_ with the rostellum (_basitonous_ Orchids, Fig. 320 _A_, _B_), while in all other Orchids it is connected at the apex (acrotonous Orchids). The pollen-grains in each loculus are united into small “masses” (massulæ), each of which corresponds to a pollen-mother-cell in the anther, and which hang together by elastic threads (Fig. 320 _C_, _E_). Each pollinium is attached at the base by a stalk (caudicle) to an adhesive disc, formed by the modified stigma (rostellum), and is easily liberated from it (Fig. 320 _C_, _D_, _F_). The pollinium, which is formed in an anther-loculus, together with its caudicle and adhesive disc, is termed “pollinarium” (Fig. 320 _C_).--All Ophrydeæ are terrestrial with _tuberous roots_, two of which are present in the flowering period, an older one (from the preceding year) containing the nourishment for the flowering-shoot of the year, and a young one which is intended to contain the reserve material for the following year. Inflorescence terminal.

_Orchis._ The lip has a spur; each of the club-like pollinia is attached to its own adhesive disc, the discs being enclosed in a common pouch formed by the rostellum (Fig. 320 _C_, _D_). ~Tubers ovate, undivided: _O. morio_, _mascula_; tubers palmate: _O. incarnata_, _maculata_, _majalis_.~--_Ophrys_; no spur, the two adhesive discs are each enclosed in a separate pouch (Fig. 320 _F_).--_Anacamptis_ and _Serapias_ have one adhesive disc.--_Habenaria_, _Gymnadenia_, _Platanthera_, _Herminium_, _Nigritella_, _Cœloglossum_, etc., have naked adhesive discs (no rostellum).

=5.= EPIDENDREÆ. Acrotonous Orchids with deciduous anthers
(except _Malaxis_); 2-8 wax-like pollinia, with or without
caudicles; generally no adhesive discs. _Malaxis_ (the flower is
twisted through a complete circle, causing the labellum to be
turned upwards), _Sturmia_ and _Corallorhiza_[32] (Coral-root);
the latter has a creeping, coral-like rhizome _without roots,
and is destitute of chlorophyll_ except in the ovary. The
other two somewhat resemble the tropical Orchids in having the
lower internodes of the axis of the inflorescence tuberous.
_Liparis_; _Calypso_. Most of the genera are tropical epiphytes
and many have aerial, green tubers formed from one or more
stem-internodes; _Dendrobium_, _Eria_, _Phaius_, _Bletia_,
_Epidendrum_, _Cattleya_, _Lælia_, _Pleurothallis_, _Restrepia_,
_Masdevallia_, _Bulbophyllum_, etc.

=6.= VANDEÆ. These resemble the preceding but have only 2
wax-like pollinia in each anther, which are attached by a
caudicle to the adhesive disc of the rostellum. Nearly all are
tropical epiphytes. _Stanhopea_, _Catasetum_, _Maxillaria_,
_Oncidium_, _Vanda_, _Polystachya_, etc.

6,000 (10,000?) species. The majority live in the Tropics and
occur, especially, as epiphytes on trees or in the crevices of
rocks, to which they are attached by aerial roots. These _aerial
roots_, like those of Araceæ, are covered by several layers of
spirally-thickened cells (tracheides) which contain air and form
the velamen--an apparatus to absorb moisture from the air. The
roots have a white appearance when the cells are filled with
air, which changes to a greenish hue when they are filled with
water, the chlorophyll then shining through. They generally
have horizontal rhizomes; the ascending shoots, which bear the
foliage-leaves, may vary, but they very often swell and assume
the form of a tuber, which persists for several years fresh and
green after the leaves have fallen off (Fig. 321). _Vanilla_
is an exception (see above). Our Orchids are all terrestrial
(or marsh-plants); the largest number of species is found in
calcareous soils.

POLLINATION takes place principally by means of insects,
but self-pollination occurs in some. The lip serves as a
landing-stage for the insect visitors, which, on sucking the
honey, cause the adhesive discs, with the pollinia attached to
them, to adhere to their bodies (generally to the probosces)
and so carry them away to other flowers. In some species parts
of the flower are sensitive or irritable, which has some
connection with the pollination. Without doubt there are a great
many biological differences which are closely connected with
the infinite multiplicity of forms; Darwin (1862) has already
shown an enormous variety, never even dreamt of before, in the
European species. The genus _Catasetum_ has ♂-♀-and ☿-plants
with flowers of such different appearances that they have
been classed in various genera (_Myanthus_, _Monacanthus_).
_Platanthera_ is pollinated by hawk-moths; _Ophrys_, by flies;
_Epipactis latifolia_, by wasps; _Orchis_, by bees, especially
humble-bees, etc.

The DISTRIBUTION OF SEEDS is effected by the wind, the seeds
being so exceedingly small and light. Many species moreover have
peculiar, elater-like, fine, hygroscopic hairs in the ovary,
which eject the seeds in a manner similar to the elaters of the
Liverworts.

The USES are few, mostly as ornamental plants in conservatories.
The tubers of several _Orchis_-species are OFFICINAL; they
contain starch and mucilage and are used us “salep.” The fruits
of _Vanilla planifolia_ are used as condiments and differ from
other _Orchid_-fruits in being rather fleshy and in dehiscing
irregularly; the seeds are very small, shining and black.

Class II. =Dicotyledones.=

In this class THE EMBRYO has 2 seed-leaves, a rule from which there are few exceptions (_e.g. Ficaria_, _Cyclamen_, _Pinguicula_, certain species of _Corydalis_, with only 1; and a few, mostly parasitic forms, _e.g. Monotropa_, _Orobanche_, _Pyrola_, entirely without cotyledons). On germination the cotyledons nearly always raise themselves above the ground as green, assimilating leaves and are then termed aerial or epigean, in contradistinction to the underground or hypogean which are always buried. The structure of the seed varies (endospermous or exendospermous); the embryo may be straight or curved. In many instances the primary root grows as a vigorous tap-root, with weaker branches arising acropetally (in annuals, biennials, many perennials, especially woody plants); but in a large number of herbaceous perennials, which have rhizomes, the root behaves very much as in the Monocotyledons. The roots generally increase in thickness by means of a cambium.

THE STEM, when seen in transverse section, has its vascular bundles arranged in a ring; in reality, however, they form a kind of cylindrical network in the stem; the bundles are open, and thickening takes place by means of a cambium; annual rings are formed in the perennial stems. There is a rich and very varied form of _branching_. The two first leaves of a shoot (fore-leaves) are placed nearly always to the right and to the left; the same arrangement is found in the two first leaves developed on the flower-stalk, and these are, as a rule, the only two; they are found below the calyx and are usually termed the “_bracteoles_.” It has become customary to indicate the bracteoles by the letters α and β, according to their sequence of growth, and in that sense these letters will be employed in the following diagrams.

THE ARRANGEMENT OF THE LEAVES varies very much; there is also a great variety of shapes in the leaves and their venation, but the linear leaves, with parallel venation, so frequent in the Monocotyledons, are seldom met with, as also the large sheaths (though the sheath is well developed in the Umbelliferous plants); stipules occur much more frequently.

THE FLOWER is most commonly cyclic, but acyclic or hemicyclic forms also occur. The type which may be taken as a basis consists in the majority of instances, as in the Monocotyledons, of 5 whorls, of which the 4 outer ones (calyx, corolla, and the 2 whorls of stamens) are most frequently 4 or 5 in number and placed in regular alternation, whilst the innermost one (the carpels) has generally fewer members, probably on account of space (Figs. 360, 361, 421, 429, 487, etc.). Trimerous (Figs. 384, 387, etc.) flowers, or those in which the members of the flower are in threes or a multiple of three, also occur, as well as dimerous flowers; other numbers are rare. It is of the greatest importance in connection with the relative position of the members of the flower to the axis and bract (orientation), whether the bracteoles are typically present (even though they may not be developed), or are typically absent. If there are 2 bracteoles present, then their position in a pentamerous flower is often as follows: the first sepal turns obliquely forward, the second is posterior and median, the third obliquely forward, the fourth and fifth obliquely backward; quincuncial æstivation is often found in these buds (Figs. 360, 429, 471, 475, 584). The first and third leaves, in the following chapters, are most frequently alluded to as the “anterior,” the fourth and fifth as the “lateral” leaves. The _reversed_ arrangement, with the median sepal in the front, occurs for instance in _Papilionaceæ_ (Fig. 511), _Lobeliaceæ_ (Fig. 594), _Rhodoracecæ_. If any bracteoles are present below a tetramerous flower, the relation is generally that 2 sepals (the first ones) stand in the median plane, the two next ones transversely (Fig. 393), and the corolla then adopts a diagonal position (Fig. 397); but a diagonal position of the calyx generally shows that the flower is not, strictly speaking, tetramerous, as in _Plantago_ (Fig. 567), _Veronica_ (Fig. 559 _C_) and others.

If the bracteoles are _not_ typically present, then the position of the sepals is changed accordingly, and the two outer sepals endeavour to assume the position which the bracteoles would otherwise have occupied, _e.g._ in _Primula_ (Fig. 547). Other positions are also found when the number of bracteoles is more or less than two.

The leaves which follow the sepals occupy definite positions with regard to them, which we may consider later. An arrangement must, however, be mentioned here; when the flower is “_diplostemonous_” that is, has two whorls of stamens (thus, Sn, Pn, An + n), these may be arranged in two ways. _Either_ the first-formed whorl of stamens, which are termed the “calyx-stamens,” stands directly in front of the sepals (that is “episepalous”), and is the _outermost_ whorl, and in this case a regular alternation takes place between sepals, petals and the two whorls of stamens, which is also continued into the carpels if their number is the same as that of the other whorls: the carpels are then placed opposite the sepals (Fig. 278) and the flower is _isomerous_ and Gn should be added to the formula above. _Or_, the calyx-stamens form the _innermost_ whorl, and the corolla-stamens, which are subsequently formed (“epipetalous” stamens), stand _outside_ these (Figs. 360, 429); if the number of carpels is the same as that of the preceding whorls, they are often placed _right in front_ of the petals and the corolla-stamens. The first-mentioned arrangement is termed _Diplostemonous_, and the second _Obdiplostemonous_. ~Both arrangements may be found in one and the same order, _e.g._ Caryophyllaceæ. The size and relation of the members of the flowers, and also the contact with other members in the early stages of their development, play an important part in determining the arrangement.~

The great number of structural arrangements found in this enormously large class, may, as is the case in the Monocotyledons, be further varied by _suppression and division_ of certain leaves (especially the stamens). Instances of this will occur in the following (Figs. 559, 568.--426, 441, 445, etc.).

The Dicotyledons were formerly divided into 3 sub-classes: Apetalæ (those without corolla), Sympetalæ or Gamopetalæ (those with the petals united), and Choripetalæ or Polypetalæ (the petals not united). This division has now been abandoned because it has been proved that the Apetalæ were merely reduced or incomplete forms of the Choripetalæ, and they have therefore been distributed among the various families of the latter sub-class.

With regard to the Sympetalæ (or Gamopetalæ) it may be stated that they form to a very great extent a closely connected and natural group, having in common not only the character that the corolla is gamopetalous and the stamens united with it (this being also found in the Choripetalæ), but also a great many others (such as persistent calyx, cyclic flowers with the formula S5, P5, A5 and as a rule G2, the two carpels being united to form the ovary; seeds with a thick integument and a very small nucellus). They are therefore considered as an independent sub-class, and must be placed at the close of the system of classification as the forms which presumably have arisen the latest. In the future systems of classification this arrangement will very probably be changed, and the first families of the Sympetalæ, the Bicornes and others will for instance be to a certain extent united with the families or orders of the Choripetalæ. The Sympetalæ may certainly be considered as the youngest types, the strongly pronounced metamorphosis supporting this theory, as also the formation of the integument of the ovule, the one thick integument being undoubtedly derived from the coalescence of two--a holochlamydeous ovule, etc.

The Apetalæ and Choripetalæ are united into one sub-class. The leaves of the perianth in this case are, as a rule, free from each other, the structure of the flowers presents many differences, and the ovules have as a rule 2 integuments and a large nucellus. Considerable uncertainty still prevails regarding the arrangement and the relationship of the individual families of the Choripetalæ, and some of the following families are hardly quite natural; but the best arrangement arrived at so far has been adopted here.

At the beginning of the book a review of the orders of the Dicotyledons will be found.

Sub-Class 1. =Choripetalæ. Petals free.=

Family 1. =Salicifloræ.=

Trees and shrubs, which, in the structure of the vegetative shoot and the catkin-like inflorescences, resemble the Quercifloræ, but the structure of the flower differs so much from them, that the only order brought under this heading--_Salicaceæ_--well deserves to be separated and to form a family of its own, the nearest relatives of which are still doubtful. ~As Juglandaceæ and Myricaceæ also deserve to be placed in a special family, the name _Amentaceæ_ (_Catkin-bearers_), hitherto applied to all of these plants, cannot be retained as the name of a family.~

There is only one order.

Order. =Salicaceæ= (=Willows=). Trees with simple, scattered, _stipulate leaves_. _Diœcious_. The flowers are arranged in _simple inflorescences_ (spikes or racemes) which are termed catkins, and which fall off as a whole after flowering (♂) or after the ripening of the fruit (♀) (Fig. 322). The perianth is very imperfect[33] or wanting, particularly in _Salix_ (Fig. 323 _o_); the ♂-flower with 2–several stamens and without any trace of a carpel (_a_, _b_, _c_): the ♀-flower has a free bicarpellate ovary, _unilocular_, and formed from 2 lateral carpels with 2 _parietal_ (_median_) _placentæ_ and generally ∞ ovules; the style divides into two stigmas (_d_, _e_, _f_). The fruit is a two-valved _capsule_ and the very small seeds bear a _tuft of hairs_ at the base. _Endosperm absent._--~The catkins are situated on dwarf-branches, which in some species often develop before the leaves and bear at their base only scale-leaves; in others foliage-leaves are borne beneath the catkins. The vegetative bud commences with 2 bud-scales which are united on the anterior side into a scale. The capsule opens by the dorsal suture. The seed-hairs spring from the funicle.~

_Salix_ (Willow) has short-stalked, most frequently lanceolate leaves and erect catkins with undivided bracts (Fig. 322). The flowers are naked; 1 (_o_ in _a-f_) or 2 yellowish glands situated in the median line. In the ♂-flower generally two stamens, situated laterally like the carpels in the ♀-flower. ~Various forms are seen in Fig. 323.--The terminal bud of the branches often aborts regularly, the uppermost lateral bud taking its place.~

_Populus_ (Aspen, Poplar) has long-stalked, more or less round or cordate leaves with drawn-out apex; catkin pendulous; lobed bracts; perianth cup-like with oblique edge; stamens usually numerous; stigmas often divided.--~_P. tremula_ (Aspen) has received its name from the tremor of the leaves: _cf._ “to shake like an aspen leaf.”~

POLLINATION. The Poplars are wind-pollinated. The Willows have
sticky pollen and are pollinated by insects. The catkins of
the Willows, especially the ♂, are more conspicuous, from the
numerous, closely-packed, yellow flowers, rich in honey and
pollen. The catkins often appear before the foliage and so
are much more easily seen, whilst at this time of the year the
number of competing honey-flowers is smaller, and the insect
visits consequently more numerous. On many catkins of the Willow
the flowers open earliest on the side which is turned towards
the sun and in descending order, _i.e._ the upper flowers
develop before the lower ones. Hybrids frequently appear.

There are about 180 species existing in the northern, cold and
temperate latitudes. Some in the Polar regions are scarcely more
than an inch in height, and have a creeping rhizome (_Salix
herbacea_, _polaris_, _reticulata_). Fossil forms are found in
the Tertiary and perhaps also in the Upper Cretaceous.

USES. Principally for ornamental trees, as they grow very
quickly and are easily propagated by cuttings, _S. babylonica_,
Weeping Willow; _S. purpurea_; _Populus alba_, Silver Poplar;
_P. pyramidalis_, Pyramid Poplar--a form of _P. nigra_; _P.
monilifera_, Canadian Poplar. The wood is very poor and
little used; the branches of many Willows are cultivated for
basket-making, etc. The wood of the Aspen is used for matches.
The bark contains tannin and, in many Willows, a very bitter
extract, _Salicin_ (_S. pentandra_, _fragilis_). Salicylic
acid (officinal) is obtained from _Salix_. Balsam is extracted
from the buds of many Poplars, especially when the leaves are
shooting.

Family 2. =Casuarinifloræ.=

Trees with verticillate, scale-like leaves forming sheaths at the nodes. Monœcious. Flowers unisexual. ♂-flowers in catkins; ♀ in short spikes. _Pollen-tube entering the ovule at the chalaza_, and not through the micropyle. Ovary 1-seeded, unilocular. Carpels uniting into a multiple fruit. Only one order.

Order. =Casuarinaceæ.= Trees (30 species), from Australia and certain parts of S.E. Asia, with peculiar, equisetum-like appearance. The leaves are verticillate, scale-like and united into sheaths. The internodes are furrowed. Branching verticillate. The unisexual flowers are situated in catkins or short spikes. The ♂-flower has a central stamen, surrounded by 2 median, scale-like perianth-leaves and 2 lateral bracteoles. The ♀-flower has a 1-chambered ovary (2 ascending, orthotropous ovules), no perianth, but 2 large, lateral bracteoles which finally become woody and form two valves, between which the nut-like fruit is situated. The multiple-fruits therefore resemble small cones.--_Casuarina equisetifolia_, cultivated, gives “iron-wood.”

[The Casuarinas differ from the ordinary Dicotyledons in many
important respects which may be briefly summarised thus:--The
bicarpellate ♀-flower has a well-pronounced stylar-cylinder
terminated by two stigmas, but the cavity of the ovary closes
very soon after its formation, and in it are developed two
parietal ovules; these are united by a bridge of cellulose to
the stylar-cylinder or summit of the ovary, and hence the ovules
are connected with the walls of the ovary by the bridge (above),
as well as by the funicle (below). The archespore is developed
from the hypodermal cells at the summit of the nucellus,
two primordial mother-cells are first formed and from these
by tangential divisions a central cylindrical mass of cells
(sporogenous-tissue) is produced which is surrounded by tapetal
cells. The cells of the sporogenous tissue correspond to the
mother-cells of the embryo-sac of other Angiosperms; they divide
transversely and from 16–20 macrospores are formed together with
inactive cells which are not crushed together as in the case
of other Phanerogams. The sexual apparatus is developed from a
single cell, but the number of cells composing this apparatus
is subject to variation, the oosphere being accompanied by one
or two neighbouring cells which resemble canal-cells rather
than synergidæ. The sexual apparatus is found in the majority
of the macrospores, but in most of these it remains as a number
of naked cells; while in the fertile macrospores the cells
are invested by walls of cellulose (usually only one fertile
macrospore is found in each ovule). Antipodal cells are never
developed. The macrospores elongate considerably towards the
chalaza, into which some penetrate. The pollen-tube traverses
the stylar-cylinder and enters the ovules at the chalaza, its
passage through the tissue of the nucellus being assisted by
the prolongation of the macrospores. About the centre of the
nucellus the pollen-tube is ruptured; the apical portion which
alone takes part in the fertilisation being firmly attached to
the macrospore. Although the actual impregnation has not been
observed, Treub considers that the endosperm begins to be formed
before fertilisation.]

Family 3. =Quercifloræ.=

_Trees_ and _shrubs_ with small, unisexual, _monœcious_ flowers, having no perianth or a simple inconspicuous one. The ♂ and ♀ flowers are very different and generally placed in separate inflorescences. The ♂-flowers are most often adnate to the bracts. The stamens are placed _opposite the perianth-leaves_, when they are present in equal numbers. The ♀-flower is _naked_, or has a _superior_ perianth. The ovary at the base is 2- or 3-(-6) locular with 1 or 2 pendulous ovules in each loculus, only one of which is developed; the fruit is a one-seeded _nut_; _endosperm absent_; embryo straight. The inflorescences, which are either compound and mixed (small dichasia in spikes) or simple, are here also termed _catkins_; but, strictly speaking, this term is applied to the ♂-inflorescences only. In all Quercifloræ the leaves are _scattered_ (usually in 2 rows) _simple_, and _penninerved_, and with _deciduous stipules_.