Chapter II: ACROGYNÆ. The apex of the stem or of certain branches is adapted (3)

If, in commencing our consideration of the _female flower_, we begin with that of _Ginkgo_, we shall observe in the corner of a scale- or foliage-leaf a small flower, which consists of two carpels, each bearing one ovule, and reduced almost to the ovule itself (Fig. 260 _C_, _D_). The flower in _Podocarpus_ is still further reduced, viz. to a single carpel with one ovule, which is anatropous and has two integuments. This ovule is situated in the axil of a cover-scale (_c_, in Fig. 262 _D_), and several female flowers of this description are collected in a small cone, the stalk and bracts of which become fleshy (Fig. 262 _C_). The external integument also becomes fleshy (an aril). _Dacrydium_, which is clearly related to _Podocarpus_, has an external integument which developes more independently as a fleshy aril (Fig. 262 _B_, _B’_). _Microcachrys_ also is clearly allied to these: the bracts are more fleshy, and the ovule (_i.e._ the female flower) is protruded beyond the bract (Fig. 262 _A_, _A’_). _Taxus_ stands in a more isolated position: a flower which has been reduced to an ovule is situated, in this instance, on the apex of a secondary branch which is studded with floral-leaves (Figs. 263, 264); an external integument is developed on all sides and surrounds the seed as a scarlet aril. According to this conception _the aril corresponds to an external integument_, and the Taxoideæ thus possess a partly dichlamydeous ovule. Only _Ginkgo_ and _Cephalotaxus_ appear to deviate from this, as in these there is only one integument (unless the small outgrowth indicated by _ar_, in Fig. 260 _D_, really is a rudimentary, external integument); in CYCADEÆ, to which _Ginkgo_ is most closely related, there is likewise only one integument. But in these genera the testa is differentiated into two layers, and the seed resembles a drupe; like the Cycadeæ there is an external fleshy covering and an internal hard one, and these two layers may probably be considered homologous with the two integuments. This theory is also borne out by the arrangement of the vascular bundles in _Cephalotaxus_ and _Podocarpus_, which present the xylem in the fleshy external layer to the _outside_ of the testa, which is therefore the upper side of the integument (Celakovsky).

The coalescence of the integuments into one is only slight in _Torreya_, more pronounced in _Podocarpus_ and strongest in _Cephalotaxus_ and _Ginkgo_. Celakovsky terms these ovules “holochlamydeous.”

If we pass from these to the order PINOIDEÆ, we find the female flowers collected into catkin-like cones, which have been considered from various points of view to be sometimes single flowers, at other times compound inflorescences. The structure in ABIETACEÆ is as follows: a number of spirally arranged, scale-like leaves, _cover-scales_ (Figs. 267, 268), are situated on a long axis. In the axil of each cover-scale a larger leaf-like projection, _the ovuliferous scale_, is borne, which turns the upper side towards its cover-scale (which is shown by the fact that the wood of its vascular bundles is turned downwards and towards the wood in the bundles of the cover-scale: Fig. 269). Two ovules, with micropyles turned towards the central axis, and with apparently only one integument (Fig. 268), are situated on the dorsal side of each ovuliferous scale, _i.e._ the side turned away from the cover-scale. The ovuliferous scales grow after fertilisation, into the woody or leathery “cone-scales,” which are usually much larger than the cover-scales. This ovuliferous scale with its axis may, according to Celakovsky, be considered as a dwarf-branch which is situated in the axil of the cover-scale, and bears two ovules (in the same way as in _Ginkgo_, one long-stalked flower, reduced to two ovules, is situated in the axil of a leaf), and _in this case the external integument of the ovules_ is expanded into leaf-like bodies, which have united to form one “_symphyllodium_” (_ovuliferous scale_) which is inverted so that its dorsal side is turned upwards and bears the nucellus and the other integument (“hemichlamydeous” ovules). The carpel itself is therefore in this instance extremely reduced. The keel, or (in _Pinus_) “mucro” (Fig. 268 _B_), which is found in several genera, represents then a third carpel, which is sterile. In the other orders of the Pinoideæ the cover-scales and ovuliferous scales grow more and more together and finally form one structure, which also is termed a “cone-scale,” although from its development it cannot be homologous with the cone-scales of the Abietaceæ. This connation is least in the TAXODIACEÆ and ARAUCARIACEÆ and may be traced on the upper surface of the “cone-scale” by the presence of a stronger or slighter ridge or pad, the free portion of the ovuliferous scale (Figs. 256, 266, 269). It is most strongly pronounced in the CUPRESSACEÆ, in which the two scales form one single structure, the cone-scale (Fig. 274). The vascular bundles in the under portion corresponding to the cover-scale, have the xylem towards the upper side as usual in leaves, whilst the bundles present in the upper side of the cone-scale, which thus represents the ovuliferous scale, turn their xylem downwards. The hemichlamydeous ovules are then situated on the upper side of this cone-scale. According to this theory the CUPRESSACEÆ appear to be the youngest type, a view which corresponds with their vegetative structure. If there is only one ovule in these orders as in _Agathis_ (Fig. 265) and _Araucaria_, then the flower is reduced to a single carpel and one ovule, as in the case of _Dacrydium_ and _Microcachrys_. If two or more ovules are present, then the same number of carpels may be supposed to exist, the external integuments of their ovules being developed into leaf-like structures which collaterally coalesce to form a “symphyllodium,” or are suppressed.

According to this theory, which is based on the researches of Celakovsky, the female flowers of the Coniferæ may be classed thus:--

1. In all cases situated in the axil of a bract and collected into cones, with numerous flowers or with few or one flower. In _Ginkgo_ only, are they situated in the axil of foliage- or scale-leaves.

2. It is only in _Taxus_ that bracteoles are present.

3. They are formed only from rudimentary carpels, in which the stem takes no part.

4. The number of carpels in each flower varies from one to many, most frequently three, of which the central one remains sterile.

5. Each carpel bears only one ovule. The flower which is formed of only one carpel appears to consist of only one ovule.

6. The ovule has in Taxaceæ either a double integument (Podocarpeæ, Taxeæ), of which the external is the “aril,” or, as in the Cycadeæ, a single one, which is homologous with the two united together.

7. The external integument in the Pinoideæ is expanded to form a leaf-like structure--the ovuliferous scale--and bears on its dorsal side the ovules, which are thus only provided with one, and that the inner, integument.

This later interpretation of the female cones in the Coniferæ is
more probably correct than the older ones; that, however, which
appeared in the former issues of this book, may also be stated.
It was to the effect that each catkin-like female cone is in
reality a single flower; the cone-scales in the Cupressaceæ
were single leaves, namely carpels, which bore the ovules on
the side which is turned upwards; the division into two parts
which makes its appearance in the other orders, and becomes
most prominent in the Abietaceæ, was compared with the division
of a leaf into a barren and a fertile portion, which is found
especially in Ophioglossaceæ and Marsiliaceæ, or with the ligule
in _Isoëtes_.

POLLINATION is accomplished by means of the wind. At the period of pollination the leaves are always so widely separated from one another, that the ovules can catch the pollen-grains carried to them by the wind; this is often effected by the mucilaginous drops which appear at the micropyle, and by the evaporation of which the pollen-grains are brought in contact with the nucellus. The entire cone grows considerably as soon as fertilisation has taken place, and the cone-scales in Pinoideæ close together so that the seeds while maturing are enclosed, and it is not until the seeds are ready for distribution that the cone-scales again become separated. In the Pinoideæ, the fully developed ovuliferous scales are hard and woody; and in this condition the collection of female flowers is termed a _cone_. In the Taxoideæ, true cones are the exception. 2–15 cotyledons are present, arranged in a whorl.

The characteristic feature of this class is the abundance of _resin_, which is to be found in isolated cells (especially in the cortex), partly in intercellular glands or passages (both in the cortex and wood). _Taxus_ is the only genus which has no resin.

There are about 350 species, mostly from the Northern Temperate
zone (especially North America and Siberia), where they grow
gregariously and form the most northern forests. The Juniper,
Scotch Fir, and Yew are natives of Great Britain.

This class may be divided into two families:--

1. =Taxoideæ.= The ovules have either one integument, the external part of which is fleshy, and the internal hard and stone-like; or two integuments, of which the external is the fleshy and coloured “aril.” “Ovuliferous scales” are wanting. The cones are never woody, but are generally succulent, the bracts become fleshy, or cones usually are not developed. The seeds project more or less freely beyond the bracts.

2. =Pinoideæ.= The ovules have two integuments, the external one of which is leaf-like and becomes developed as the “ovuliferous scale”; if there are several of these in each flower they unite and form a “symphyllodium.” This may remain free or unite with the bract. The cones are most frequently woody, rarely succulent. The seeds are hidden among the cone-scales.

Family 1. =Taxoideæ.=

This family, considered to be most nearly related to the Cycadeæ, also made its appearance at a very early period. There is only one order.

Order. =Taxaceæ.= The characters have been given above.

_A._ CEPHALOTAXEÆ is the oldest group, presumably the connecting link between the Cycadeæ and the other Coniferæ. The flower consists normally of two ovules. Aril wanting. One integument. Seeds drupaceous.--The flowers in _Ginkgo biloba_ (_Salisburia_) are situated in the axil of foliage- or scale-leaves. The stamens bear only two pollen-sacs (Fig. 260 _A_). The female flower has two ovules, placed together at the end of a long, bare axis (Fig. 260 _C_). Round the base of the ovule a small collar (_ar_, in Fig. 260 _D_) is found, which may probably be considered homologous with the collar-like outgrowth which surrounds the base of the _Cycas_-ovule. The seed resembles a Plum, and has a fleshy external coat, surrounding a hard internal layer. The embryo is developed after the seed has fallen off. The Ginkgo-tree has long-stalked, fan-shaped leaves, more or less indented, with dichotomous veins resembling certain Ferns--the Adiantums. It is a native of East Asia, and the only surviving species of a genus which in earlier times was very rich in species, and distributed over the entire Northern Hemisphere. _Cephalotaxus_ (Eastern Asia) is related to it.

_B._ PODOCARPEÆ. The female flower is reduced to one ovule, placed in the axil of a bract, or a little forward upon it. The ovule has an aril (2 integuments).--_Phyllocladus_ (Fig. 261), from New Zealand and Tasmania, has obtained its name from its flat, _leaf-like branches_, the leaves proper being scale-like (_f_). The ovules stand _erect_ in the axil of the scale-like leaves (_c_), and several are collected at the end of short branches.--_Microcachrys tetragona_ (Tasmania) has a small female catkin with several spirally-placed, fleshy bracts, at the end of which the inward and downward turned ovule is attached (Fig. 262 _A_, _A’_). The ripe cones are red, succulent, and resemble Strawberries.--In _Dacrydium_ (Tasmania, New Zealand, Malaysia) the female cone has most frequently only 1–2 (–6) bracts, which resemble the vegetative leaves; they have also a fleshy aril (Fig. 262 _B_, _B’_).--_Podocarpus_ (40 species, East Asia, S. Temp.); the bracts of the female flowers become fleshy, and unite together; only 1 or 2 are of use in supporting the flowers. The ovules project high above the apex of the bract, and are _anatropous_, the micropyle being turned downwards (Fig. 262 _C_, _D_). An aril commences to develope in the flowering period as an external coating, and later on it becomes fleshy and coloured.

_C._ TAXEÆ. The female flower is reduced to one ovule, which is situated _terminally_ on an axis which bears 2–3 pairs of opposite, scale-like bracteoles; on this account the Taxeæ form a very isolated group among the Coniferæ.--_Taxus_ (_T. baccata_, the Yew-tree). _Diœcious_. _The female flower consists of only one ovule_, placed _at the end_ of a short secondary branch (Fig. 264), which is studded with scale-like leaves. The aril when ripe is thick, fleshy, and scarlet (sometimes yellow), and only loosely envelopes the seed (Fig. 263). The leaves are scattered, flat, linear, and pointed (Fig. 263, 264). The short male flowers have 5–8 pollen-sacs, pendent from the stamens, and are surrounded at their bases by scale-like bracteoles (Fig. 243). _Torreya_ (4 species, N. America and Japan) is closely allied to _Taxus_. The aril ultimately fuses with the woody inner integument, and hence the ovule becomes drupaceous, as in Cephalotaxaceæ.

USES. _Taxus baccata_ is usually planted in gardens, especially
in hedges. Its wood is very hard and is used for wood-carving.
The shoots are poisonous, but not the aril, which is often eaten
by children and by birds.

Family 2. =Pinoideæ.=

The four orders differ from one another partly in the arrangement of the leaves (_Cupressaceæ_ have opposite or verticillately placed leaves, flowers, and inflorescences; in the others they are placed spirally), but chiefly in the greater or less degree of union which takes place between the female flower (the leaf-like “symphyllodium”) and its supporting cover-scale, and in the position of the ovules (the micropyle being turned upwards or downwards). The “cone-scales” in _Abietaceæ_ are formed by “symphyllodia” alone, in the others by their union with the cover-scale.

Order 1. =Araucariaceæ.= This order most frequently has _solitary_ ovules, _turned downwards_ and attached _to the centre_ of the cone-scales. In _Agathis_ (_Dammara_) the arrangement is the most simple, a winged seed (Fig. 265), which hangs _freely_ downwards, being borne in the centre of the undivided cone-scale. In _Araucaria_, the stamens with the _free, pendulous_ pollen-sacs have been represented in Fig. 242; the ovuliferous scale is united for nearly its whole length with the bract, and projects from its apex in the shape of a sheath-like, dentate scale, resembling the ligule in _Isoëtes_, and may therefore be termed a “ligule.” _Araucaria_ (S. America, Australia) has often rather broad leaves (_A. brasiliensis_). The ovuliferous scale in _Cunninghamia_ is more distinct, and stretches transversely over the entire cover-scale; it bears three inverted ovules (Fig. 266) (Eastern Asia).

Dammara-resin, which is used for varnish, is obtained from
_Agathis_ (_Dammara_) species (New Zealand, Philippine
Islands).

Order 2. =Abietaceæ (Pine and Fir Trees).= The leaves are spirally arranged and needle-like. The flowers are _monœcious_. The male flowers are long, and catkin-like, with numerous stamens, each bearing two _oblong pollen-sacs_. The pollen-grains are most frequently tri-lobed, having two bladder-like appendages, formed as outgrowths of the exospore, to assist in their distribution by the wind (Fig. 267 _N_). The bracts are arranged spirally. The union between the bract and the ovuliferous scale, which is found in the preceding order, is not in this instance so complete; these scales make their appearance as two free parts, and are attached only at their bases (Fig. 268); the lower portion, that is the cover-scale, in most instances remains quite small (Fir, Red Pine, and others), it is only in the “Noble Pine” (_Abies_) and _Pseudotsuga douglasii_, that it attains a greater length than the ovuliferous scale (Fig. 267, _B-G_). On the other hand the upper part, _the ovuliferous scale_ (the vascular bundles of which have the bast turned upwards), grows strongly and elongates, especially after fertilisation, becoming woody or leathery; it is commonly termed the “_cone-scale_,” but is in reality only homologous with a part of the “cone-scale” in the other order of Pinoideæ. On the side of the ovuliferous scale, turned towards the axis, are situated _two ovules_ with micropyles _directed inwards_. The seeds are most frequently provided with _a false wing_ (a tissue-like part of the surface of the ovuliferous scale). Cotyledons, _more than_ 2, _verticillate_. _Fertilisation does not take place until some time after pollination._ In _Pinus_, for instance, the pollen-tube only penetrates the nucellus for a short distance during the year of pollination, and then ceases its further growth, fertilisation not taking place until after the middle of the next year; whilst the seeds ripen about a year and a half after pollination. In the Larch and others, the seeds are mature in the autumn succeeding pollination.

_Abies_ (Fir). The leaves are often (_e.g. Ab. pectinata_) displaced into 2 rows, flat and indented at the apex, with 2 white (wax-covered) lines on the under surface, in which the stomata are situated. The leaf-scars are nearly circular and do not project. The cones are erect. _The cover-scales and the ovuliferous scales separate from the axis_, to which they remain attached in other genera.--~_Tsuga_ has leaves like _Abies_, but by the slightly projecting leaf-scars, and cones with persistent scales, it forms the transition to _Picea_.--_Pseudotsuga_ has leaves similar to those of _Abies_ and persistent carpels as in _Picea_, but the cover-scales grow as in _Abies_ and project beyond the ovuliferous scales (_P. douglasii_, Fig. 267). These two genera are considered as sub-genera of _Abies_.~--_Picea_. The leaves project on all sides, square and pointed; the leaf-scars are rhombic, on projecting leaf-cushions. The cones are pendulous. The cover-scales are much shorter than the leathery, persisting ovuliferous scales.--The genus _Larix_ (Larch) differs from all the others in having deciduous leaves (the three preceding have leaves which persist for eleven to twelve years). It has _long-branches_ with linear foliage-leaves and short, thick, _perennial dwarf-branches_, which each year form a new rosette of foliage-leaves, similar to those on the long-branches. The male flowers and the erect cones resemble those of _Picea_, and are borne on dwarf-branches.--_Cedrus_ (Cedar) resembles _Larix_ to some extent, but has persistent leaves (_C. libani_, _C. deodara_).--_Pinus_ (Pine) has long-branches and dwarf-branches. The leaves of the long-branches are scale-like and not green; the dwarf-branches have very limited growth, and persist for three years; they arise in the axils of the scales borne on the long-branches of the self-same year, and each bears 2–5 foliage-leaves, they are also surrounded at the base by a number of membranous bud-scales. The cone-scales have a _thick, rhomboid extremity_ (the “shield”).

The buds which develope into long-branches arise at the apex of
other long-branches, and being very close together, form false
whorls. The female cones occupy the position of long-branches,
and take about two years for their development. The male flowers
arise close together, and form a spike-like inflorescence at
the base of a long-branch of the same year. The male flowers
occupy the position of dwarf-branches, so that a female cone
may be considered to be a modified long-branch, and a male cone
a modified dwarf-branch. The main axis of the seedling has
needle-like leaves, similar to those found on the older parts,
and on dwarf-branches; it is not until some time later that
the dwarf-branches are developed and the permanent arrangement
attained.

USES. Several species are commonly cultivated in this country,
partly on heaths and moors, and partly in plantations and as
ornamental trees, such as Mountain Pine (_Pinus montana_, Cen.
Eur.); Austrian Pine (_P. laricio_, Eur.); Scotch Fir (_P.
silvestris_, Eur.); Weymouth Pine (_P. strobus_, N. Am.); common
Red Pine (_Picea excelsa_, Cen. and N. Eur.); White Pine (_P.
alba_, N. Am.); _Abies pectinata_ (Common Fir, S. and Cen. Eur);
_A. nordmanniana_ (Crimea, Caucasus); _A. balsamea_ (N. Am.);
_Tsuga canadensis_ (N. Am.); _Pseudotsuga douglasii_ (N.W. Am.);
Larch (_Larix europæa_, Alps, Carpathians); _L. sibirica_ (N.E.
Russia, Siberia).--The wood of many species, especially Pine,
on account of its lightness and because it is so easily worked,
is very well adapted for many useful purposes. The wood of the
Yew-tree is very hard and is used for ornamental turning. Resin
and Turpentine (_i.e._ Resin with essential oils, the name being
derived from the Terebinth-tree, from which formerly a similar
material was obtained) are extracted from _Pinus laricio_ and
_P. pinaster_. Oil of Turpentine is obtained by distillation of
turpentine with water; Tar by dry distillation of Pine-wood.
Canada-balsam is from North American _Abies_-species (_A.
balsamea_ and _Fraseri_). The officinal Turpentine is mainly
obtained from _Pinus pinaster_ (South of France), _P. tæda_,
_australis_, _strobus_ (Weymouth Pine) and other North American
species; more recently also from _P. silvestris_ (Scotch Fir),
_maritima_, _laricio_, _Picea excelsa_, and others; Venetian
Turpentine, from Larch (S. Eur.) Amber is resin from a Tertiary
plant (_Pityoxylon succiniferum_), closely related to the Pine,
which grew especially in the countries round the South-East
coast of the Baltic. _Pinus pinea_ (the Pine, S. Eur.) has
edible seeds and also _P. cembra_ (in Cen. Eur. and Siberia).

Order 3. =Taxodiaceæ.= The vegetative leaves and cone-scales are arranged spirally. The ovules (2–9) are situated either at the base of the ovuliferous scales, in which case they are erect; or at their centre, when they are generally more or less inverted. The ovuliferous scale is more or less united with the cover-scale, and projects beyond the surface of the cone-scale, like a comb (Fig. 269). The vascular bundles, which extend into the cover-scale, have the usual leaf-arrangement, viz. the wood placed above the bast; while those bundles which enter the ovuliferous scale have this arrangement of the bundles reversed.

_Taxodium distichum_ (the North American “Swamp Cypress”) has
annual dwarf-branches, with distichous leaves, and cone-like
“pneumathodia.” In the Tertiary period it was very common in
the Polar regions. _Sequoia (Wellingtonia) gigantea_ is the
famous Californian Giant-Fir, or Mammoth-Tree, which attains
a height of 300 feet, a diameter of 36 feet, and is said to
live for 1,500 years. _Cryptomeria japonica_ (Japan, China) has
the least adnate ovuliferous scales; _Glyptostrobus_ (China);
_Arthrotaxis_ (Tasmania); _Sciadopitys verticillata_ (the only
species in Japan) has, like _Pinus_, scale-like leaves on
the long-branches, of which those which are situated at the
apex of the annual shoots support “double needles,” _i.e._
_dwarf-branches_ similar to the two-leaved dwarf-branches in
_Pinus_, but without bud-scales, and with the two leaves fused
together at the edges into one needle, which turns its upper
surface away from the long-branch.

Order 4. =Cupressaceæ= (=Cypresses=). _The leaves are opposite or verticillate_, sometimes acicular, but most frequently scale-like (Fig. 270). In the species with scale-like leaves, the seedlings often commence with acicular leaves (Fig. 272), and branches are sometimes found on the older plants which revert to this form, seeming to indicate that the acicular leaf was the original form (atavism). The so-called “_Retinospora_” species are seedling-forms of _Biota_, _Thuja_, _Chamæcyparis_, which have been propagated by cuttings, and retain the seedling-form. The flowers are monœcious or diœcious. The male flowers are short, and have shield-like stamens, bearing most frequently several pollen-sacs. The cover-scales and ovuliferous scales are entirely fused together and form _undivided_ cone-scales, _opposite or whorled_; _the ovuliferous scales_ have slight projections near _the base_ on which 1–2–several _erect ovules_ are developed (Fig. 274). Most frequently 2 cotyledons.--_Evergreen_ trees and shrubs.

_Juniperus_ (Juniper). _Diœcious._ The cone-scales become fleshy and fuse together to form most frequently a 1–3 seeded “berry-cone.” ~_J. communis_ (Common Juniper) has acicular leaves, borne in whorls of three, and the “berry-cone” is formed by a trimerous whorl of cone-scales (Fig. 273). _J. sabina_ and _J. virginiana_ have “berry-cones” formed from several dimerous whorls of cone-scales; the leaves are connate and opposite, needle-and scale-like leaves are found on the same plant.~

_Cupressus_ (Cypress). _Monœcious._ The cones are spherical; the cone-scales shield-like, generally five-cornered and woody (Fig. 270), each having many seeds. The leaves are scale-like.--_Thuja. Monœcious._ Cones oblong. The cone-scales are dry, as in the Cypress, but leathery and imbricate, and not shield-like; each cone-scale bears 2–3 seeds. The leaves are most frequently dimorphic; those leaves which are situated on the edges of the flat branches are compressed, and only these bear buds, which are developed with great regularity, generally alternately, on both sides of the branch; those which are situated on the flattened surfaces are pressed flat and broad, and never bear branches (Fig. 271). Along the central line of each leaf there is a resin-canal (Fig. 271).--~_Chamæcyparis_, _Callitris_, _Libocedrus_, _Thujopsis_ (1 species: _T. dolabrata_; in Japan).~

OFFICINAL. _Juniperus sabina_ from Central and South of Europe
(the young branches yield an essential oil). The wood of _J.
communis_ is used in the production of an essential oil, and
_J. oxycedrus_ in the production of empyreumatic oil. The
“berry-cone” of _J. communis_ is officinal, and is also used
for gin.--The wood of _J. virginiana_ (N. Am.) is known as red
cedar, and is used for lead-pencils. Sandarack resin is obtained
from _Callitris quadrivalvis_ (N.W. Africa).

THE FOLLOWING ARE CULTIVATED IN GARDENS:--_Thuja occidentalis_
(Arbor vitæ) (N. Am.), and _orientalis_ (China, Japan);
_Juniperus sabina_ and _virginiana_; _Thujopsis dolabrata_
(Japan); _Cupressus lawsoniana_ (California), _C. sempervirens_
(S. Eur., W. Asia), and other species, are grown especially
in conservatories, and in Southern Europe particularly in
cemeteries.--The _Retinospora_ species which are so often
planted, do not belong to an independent genus, but are obtained
from cuttings, taken from seedling-plants with acicular leaves
(see page 267).

Class III. =Gneteæ.=

This class, independent of extinct forms, comprises the most highly developed of the Gymnosperms, partly from the circumstance that a perianth of 2–4 members encloses the _terminally placed ovule_, which is provided with one, or (in _Gnetum_) two, integuments, and partly owing to the fact that the wood has true vessels. There is only one order.

Order. =Gnetaceæ.= The three known genera differ very much in
appearance. _Welwitschia mirabilis_ (from the deserts of South
Western Africa) is the oldest (?) genus now living. It resembles
a giant radish, in that the hypocotyl is the only part of the
main axis of the stem which becomes developed. It attains a
circumference of upwards of four metres with a length of 1/2½-⅔
of a metre. It bears _only_ two oblong, leathery leaves (Fig.
275) which are torn into segments at the apex and lie on the
surface of the soil; these are the two first foliage-leaves
which succeed the cotyledons, and they are remarkable for
their enormous length (upwards of two metres) as well as for
their long duration, living as long as the plant itself. In
their axils are situated the 4-rowed, spike-like male and
scarlet-coloured female cones, upon dichotomous branches. The
perianth consists in the ♂ of 2 alternating pairs of leaves,
the inner ones of which are slightly united. The andrœcium
likewise consists of 2 whorls: the external (transverse) with
2, the internal with 4 stamens; the lower halves of the 6
filaments uniting to form a cup. Each of the terminal anthers
corresponds to a sorus of 3 sporangia, the sporangia being fused
together, and opening at the top by _one_ three-rayed cleft.
In the centre of the ♂-flower there is a sterile ovule. In the
♀-flower a perianth of two connate leaves is present.--_Ephedra_
(desert plants, especially in the Mediterranean and W. Asia)
at first sight resembles an _Equisetum_; the stems are thin,
long-jointed, and the leaves opposite, small, and united into
a bidentate sheath; ♂-perianth of two connate leaves (median
leaves); 2–8 stamens united into a column. Each anther is formed
of 2 sporangia (is bilocular). ♀ mainly, as in _Welwitschia_.
The seeds are surrounded by the perianth which finally becomes
red and fleshy. There are 30 species.--_Gnetum_ has opposite,
lanceolate, pinnately-veined, leathery leaves. They are mostly
climbers (Lianas) from Tropical Asia and America. The ♂-flowers
have a tubular perianth, (formed from two median leaves) which
surrounds a centrally-placed filament, bearing 2 anthers. In
the ♀-flower there is a similar perianth, surrounding an ovule
provided with 2 integuments. The perianth becomes fleshy and
envelops the hard seed. 20 species.

From the circumstance of _Welwitschia_ having ♂ flowers
which, besides stamens, possess also a rudiment of an ovule,
Celakovsky draws the inference that the earliest Gymnosperms
had hermaphrodite flowers which from this structure became
differentiated entirely into ♂-and ♀-flowers, with the exception
of _Welwitschia_ only, in which this differentiation was only
carried out in the ♀-flower. This theory has so far been
scarcely proved.

=Fossil Gymnosperms.=

The earliest continental plants which are known belong to the
CORDAITACEÆ, a group of plants which existed as early as the
Silurian period; they were Gymnosperms, but it has not yet been
determined whether they were Cycads or Conifers. The CYCADS,
even in the Coal period, were scarce; they attained their
fullest development in Jurassic and Cretaceous periods, during
which they were rich in species and genera, and extended as far
as the Polar regions. In addition to these, Taxaceæ, Abietaceæ,
and Taxodiaceæ appeared in the Carboniferous period. The TAXACEÆ
appear to have attained their culmination in the Jurassic and
Cretaceous periods; _Ginkgo_ appears in the Rhætic; _Torreya_,
in the Cretaceous; _Taxus_ and _Podocarpus_ in the Tertiary
periods. The ABIETACEÆ also appear in the Carboniferous;
_Pinus_ was first known with certainty in the English Weald
and in the Cretaceous; almost all other contemporary genera
are represented in this latter period. The ARAUCARIACEÆ first
appear, with certainty, in the Jurassic. The TAXODIACEÆ may
be traced back as far as the Carboniferous (?); _Sequoia_ is
first found in the lowest Cretaceous, at that period it spread
throughout the entire Arctic zone, and being represented by a
large number of species, formed an essential part of the forest
vegetation. _Sequoia_ played a similar part in the Tertiary
period. The CUPRESSACEÆ are first known with certainty in the
Jurassic, but they appeared more frequently and numerously in
the Tertiary period, in which most of the present living genera
were to be found. The GNETACEÆ, according to a theory advanced
by Renault were represented in the Coal period by the genus
_Stephanospermum_, which had four ovules enclosed by an envelope.

DIVISION V.

ANGIOSPERMÆ.

See pages 3 and 224. To this Division belong the majority of the Flowering-plants. They are divided into two parallel classes, the Monocotyledons and the Dicotyledons, which differ from each other not only in the number of cotyledons, which, with a few exceptions, is one in the former, two in the latter, but also in the internal structure of the stem, the venation of the leaves, the number of the parts of the flower, etc. ~Assuming that these two classes have sprang from a common origin, it is amongst the Helobieæ in the first, and amongst the Polycarpicæ in the second class that we might expect to find closely allied forms, which might reasonably be supposed to have varied less from this original type. As for the rest, they seem to stand quite parallel, without exhibiting any close relationship. It is scarcely proved that the Monocotyledons are the older class.~

[Our knowledge of the forms included under the Angiosperms has recently been considerably increased by Treub (_Ann. d. Jar. Bot. d. Buitenzorg_, 1891), who has shown that the Casuarinas differ in many important points from the typical Angiosperms. Among other characters the pollen-tube is found to enter the ovule near the chalaza and therefore at the opposite end to the micropyle, and Treub therefore suggests that these plants should be placed in a subdivision termed Chalazogams.

According to this view the principal divisions of the Angiosperms would be represented thus:--

=Angiospermæ.=

Sub-division. Sub-division.
CHALAZOGAMES. POROGAMES.

Class. Classes.
Chalazogames. Monocotyledones, Dicotyledones.

More recently Nawaschin (_Bull. Acad. Imp. Sci. St. Petersb._, ser. iii., xxxv.) has shown that _Betula_, and Miss Benson (_Trans. Linn. Soc._, 1894) that _Alnus_, _Corylus_, and _Carpinus_ also belong to the Chalazogams.

Our knowledge, however, is still so incomplete that one would hesitate to accord the full systematic value which Dr. Treub attaches to his discovery until the limits of the Chalazogamic group are better defined; and it would hardly be justifiable to include the Casuarinas and the above-noted genera in one family.]

Class 1. =Monocotyledones.=

_The embryo has only one cotyledon; the leaves are as a rule scattered, with parallel venation; the vascular bundles of the stem are closed, there is no increase of thickness. The flower is typically constructed of five 3-merous whorls, placed alternately._

THE EMBRYO is generally small in proportion to the abundant endosperm (exceptions, see _Helobieæ_), and its single cotyledon is often sheath-like, and very large. On the germination of the seed either the entire cotyledon, or its apex only, most generally remains in the seed and absorbs the nutritive-tissue, while the lower portion elongates and pushes out the plumule and radicle, which then proceed with their further growth. The primary root in most cases soon ceases to grow, but at the same time, however, numerous lateral roots break out from the stem, and become as vigorous as the primary root, or even more so. Increase in thickness does not take place in these roots; they branch very little or not at all, and generally die after a longer or shorter time.

THE STEM is frequently a corm, bulb, or other variety of underground stem, as the majority of the Monocotyledons are perennial, herbaceous plants; it has scattered, closed vascular bundles (Fig. 276), and no cambium by which a continuous thickening may take place. The stem of the Palms, however, attains a very considerable thickness, which is due to the meristem of its growing-point continually increasing in diameter for a lengthened period (often for many years), until it has reached a certain size. In this condition the growing-point has the form of an inverted cone, and it is only when this cone has attained its requisite size that the formation of a vertical cylindrical stem commences. Certain tree-like Liliaceæ, as _Dracæna_, _Aloe_, etc., have a continuous increase in thickness; this is due to a meristematic layer, which arises in the cortex, outside the original vascular bundles, which were formed at the growing-point of the stem. This meristem continues to form thick-walled parenchyma and new, scattered vascular bundles. The primary vascular bundles, in the Palms and others, run in a curved line from their entrance into the stem at the base of the leaf, towards the centre of the stem, and then bend outwards and proceed downwards in a direction more parallel to the sides of the stem (Fig. 277). The bundles formed later, in those stems which increase in thickness, are not continued into the leaves.

THE BRANCHING as a rule is very slight, the axillary buds of the majority of the leaves never attaining development, _e.g._ in the Palms, bulbous plants and others. As the cotyledon arises singly, the succeeding leaves also must be scattered, but they are frequently arranged in two rows (Grasses, Iris, etc). _The first leaf borne on a branch_ (the “Fore-leaf,”[24]--the bracteole, if on a floral shoot) has generally, in the Monocotyledons, a characteristic form and position, being situated on the posterior side of its own shoot, and hence turned towards the main axis; it is sometimes provided with two laterally-placed keels (Figs. 279 _f_, 290 _øi_), but the midrib is often absent. It arises in some cases from two primordia, which at the beginning are quite distinct, and thus has been regarded as formed by two leaves. It is, however, only one leaf, a fact which is evident from several circumstances, one being that it never supports more than one shoot, and this stands in the median plane (Fig. 279).

THE LEAVES are _amplexicaul_, and have a large sheath but no stipules; the blade is most frequently long, ligulate, or linear, entire, with parallel venation, the veins being straight or curved (Figs. 300, 309). Connecting the large number of veins which run longitudinally, there are as a rule only weak transverse ones. It is very rarely that other forms of leaves are found, such as cordate (Figs. 302, 312), or that the blade is branched, or the venation is, for example, pinnate or palmate (Figs. 225, 298); these deviations are especially found in the Araceæ, the Palms, the Scitamineæ (Fig. 308), the Dioscoreaceæ, and in several aquatic plants. The incisions in the Palm-leaf are derived by the splitting of an originally entire leaf.

THE STRUCTURE OF THE FLOWER is generally as follows: Pr3 + 3, A3 + 3, G3, rarely S3 + P3 with the other members unchanged.[25] Instead of 3, the numbers 2 and 4 may occur; rarely others. In all these instances there are 5 whorls, which regularly alternate with one another, most frequently in the 3-merous flower, as in the diagram (Fig. 278). This diagram is found in the following orders: Liliaceæ, Convallariaceæ, Juncaceæ, Bromeliaceæ, Amaryllidaceæ, Dioscoreaceæ, Palmæ, some Araceæ, and in some small orders, and may be considered as the typical structure and also the starting point for the exceptional orders. The ovary in many Monocotyledons has many ovules, and the fruit becomes a many-seeded berry or capsule; this form is no doubt the oldest. In others the number of seeds becomes reduced to 1, and the fruit then becomes a cypsela, or a drupe (_e.g. Gramineæ_, _Cyperaceæ_, _Palmæ_, etc).

Deviations from this typical floral structure in some instances may be traced to _suppression_, very rarely to a _splitting_ of certain members, the typical relative positions not being changed. Thus, the Iridaceæ, the Cyperaceæ, most of the Gramineæ and some Juncaceæ deviate in having only 3 stamens (Fig. 279), the inner whorl (indicated by *) not becoming developed. The Musaceæ differ in the posterior stamen not being developed; _Zingiberaceæ_ (Fig. 314), _Marantaceæ_, and _Cannaceæ_, in the fact that only 1 of all the stamens bears an anther, and the others are either suppressed or developed into petaloid staminodes, with some perhaps cleft in addition. The Orchideæ deviate in having, generally, only the anterior stamen of all the 6 developed (Fig. 280). In this, as in other instances, the suppression of certain parts of the flower is often connected with _zygomorphy_ (_i.e._ symmetry in _one_ plane), chiefly in the inner perianth-whorl, but also in the other whorls. In the Orchids, the perianth-leaf (the labellum, Fig. 280 _l_) which is directly opposite the fertile stamen, is larger and altogether different from the others. The perianth-leaves may also be suppressed; see, for example, the two diagrams of the Cyperaceæ (Fig. 284). In some orders the suppression of these leaves, which form the basis of the diagram, is so complete that it is hard to reduce the actual structure of the flower to the theoretical type, _e.g._ the Grasses (Fig. 290) and _Lemna_ (Fig. 303). In the first family, which especially comprises water-plants, a somewhat different structure is found; thus Fig. 282 differs somewhat from the ordinary type, and other flowers much more so; but the floral diagrams which occur in this family may perhaps be considered as the most probable representatives of an older type, from which the ordinary pentacyclic forms have taken their origin. In favour of this theory we have the larger number of whorls, the spiral arrangement of some of these in the flower, with a large and indefinite number of stamens and carpels, the perfectly apocarpous gynœceum which sometimes occurs, etc., etc.

The Monocotyledons are divided into 7 Families:--

1. HELOBIEÆ. This family forms a group complete in itself. It
commences with hypogynous, perfect flowers, whose gynœcium is
apocarpous and terminates in epigynous and more or less reduced
forms.

2. GLUMIFLORÆ. These have as a starting point the same diagram
as the following families, but otherwise develope independently.

3. SPADICIFLORÆ. Also an independent branch, or perhaps two
different ones which terminate in much reduced forms.

4. ENANTIOBLASTÆ. These ought perhaps to be amalgamated with the
following family.

5. LILIIFLORÆ. These advance from forms with the typical diagram
and hypogynous flower, to epigynous and reduced forms.

6. SCITAMINEÆ and

7. GYNANDRÆ. Two isolated families, which probably have taken
their origin from Liliifloræ, and have epigynous, mostly
zygomorphic, and much reduced forms.

Family 1. =Helobieæ.=

To this family belong _only water- or marsh-plants_; _the endosperm is wanting_, and they possess an embryo with a very _large hypocotyl_ prolonged downwards and often club-like. The perianth is often differentiated into calyx and corolla; the flower is regular, and in the first orders to be considered, may be reduced to the ordinary Monocotyledonous type; there are, however, _usually found two_ 3-_merous whorls of carpels_ (Fig. 282), and thus in all 6 whorls, or again, the _number of carpels may be indefinite_; the number of stamens also may be increased, either by the division of the members of a whorl, or by the development of additional whorls. _Syncarps_,[26] with nut or follicular fruitlets, are _very common_, for example, in the first orders; in the last (Hydrocharitaceæ) the carpels are not only united, but the ovary is even inferior.

The primitive type appears to be a hypogynous flower, similar
to that of the Juncaginaceæ or Alismaceæ, with several 3-merous
whorls, and free carpels, each with many ovules; the green
perianth in this instance being no doubt older than the coloured
ones. If we take a flower with this structure as the starting
point, then the family developes partly into epigynous forms,
partly into others which are so strongly reduced and exceptional
that it is scarcely possible to refer them to the ordinary
type. The family, through the peculiar _Zostereæ_, appears to
approach the Araceæ, in which _Potamogetonaceæ_ and _Najadaceæ_
are included by some authorities. However, the inclusion of
_Potamogeton_, and with it _Ruppia_ and _Zannichellia_, in the
Juncaginaceæ appears quite correct. It would scarcely be right
to separate _Zostereæ_ from these. Great stress has often been
laid upon the similarity with the Ranunculaceæ which is found
in the Alismaceæ, but it is scarcely more than an analogous
resemblance.

Order 1. =Juncaginaceæ.= The ☿, regular, _hypogynous_ flowers have the _perianth_ 3 + 3, _sepaloid_, stamens 3 + 3 (with extrorse anthers), and carpels 3 + 3 (free or united), of which last, however, one whorl may be suppressed (in _Triglochin maritima_ all 6 carpels are developed, in _T. palustris_ the inner whorl is unfertile). Inflorescence long spikes. Embryo _straight_.--Marsh-plants with radical, rush-like leaves, arranged in two rows, and often sheathing and ligulate (“squamulæ intravaginales”); the inflorescence is a spike or raceme.--_Scheuchzeria._ Carpels almost free; in each at least two ovules. Follicles.--_Triglochin_ has long, fine racemes without bracts or bracteoles; one ovule in each carpel. The carpels in the two native species are united, but separate when ripe as a schizocarp, loosening from below; they open along the ventral suture or remain closed; a linear central column remains. ~The most reduced is Lilæa (1–2 sp. Am.)--Protogynous. About 10 species. Temp. Fossils in Tertiary.~

Order 2. =Potamogetonaceæ.= The aquatic plants belonging to this order are perennial, living entirely submerged, or with floating leaves, and preferring still water. The leaves are alternate, in some linear and grass-like, in others there is an elliptical floating blade, supported by a linear submerged petiole. Axillary scales. The fruit is generally a syncarp with _nuts_ or _drupes_; the _embryo is curved_, of very various forms.

_Potamogeton_ (Pond-weed). The rhizome is creeping, sympodial (with two internodes in each shoot-generation); the inflorescence is a terminal, many-flowered spike, without floral-leaves; below it are found 2 foliage-leaves placed nearly at the same height, from whose axils the branching is continued cymosely. The flowers are ☿, 4-_merous_, naked, and consist only of 4 _stamens_, with the _connectives, broadly developed_ at the back of the anthers, _resembling a perianth_, and of 4 _free, sessile carpels_. They are common plants in fresh water. ~The spike, during the flowering, is raised above the water. Wind-pollinated and protogynous.--Closely allied is _Ruppia_ (Tassel Pond-weed), in salt or brackish water. The spike has only two naked flowers, each consisting of 2 stamens and 4 carpels. The stalks of the individual carpels are considerably prolonged.--_Zannichellia_ (Horned Pond-weed) is monœcious; the ♀-flower consists of 4 (2–9) carpels, with membranous, bell-shaped perianth; long styles; the ♂-flower has 1 (-2) stamens. _Althenia._~

_Zostera_ (Grass-wrack) is an entirely submerged, marine plant with creeping rhizome (with displacement of buds) and strap-shaped leaves. The flowering shoots are sympodia with displacement of the axes (Fig. 281). The inflorescence is a peculiar, flatly-compressed spike, on _one_ side of which the flowers are borne (Fig. 281). ~This inflorescence may be considered, no doubt correctly, to be derived from the symmetrical spike of _Potamogeton_ by strongly dorsiventral development, and by a strong suppression of the floral parts taking place simultaneously. Two rows of flowers are developed, but of these one is so pressed into the other that apparently only one is present.~ Each flower consists of only 1 stamen and 1 carpel situated at the same height (Fig. 281); the unilocular ovary encloses 1 pendulous ovule and bears a bifid style. As regards the perianth (?) one leaf may be present (_Z. nana_, Fig. 281 _D_). The pollen-grains are filamentous. Pollination takes place under water. ~_Posidonia_ and _Cymodocea_ are allied to these. About 70 species.~

Order 3. =Aponogetonaceæ.= Aquatic plants with tuberous stem. They have a single, petaloid perianth (3–2–1–leaved), most frequently 6 stamens and 3(-6) carpels. Straight embryo.--About 15 species (Africa, Madagascar, Tropical Asia and Australia).--_Aponogeton distachyos_ and _A._ (_Ouvirandra_) _fenestralis_ are grown in conservatories; the latter has lattice-like, perforated leaves.

Order 4. =Najadaceæ.= Only one genus _Najas_ (about 10 species); annual fresh water plants with leaves in pairs and solitary, unisexual flowers. The ♂ flower is remarkable in having a terminal stamen, which has either 4 longitudinal loculi or 1 central one; on this account the stamen of _Najas_ is considered by some authorities to be a stem and not a leaf-structure. The unilocular gynœceum and the single, erect, anatropous ovule are also terminal. Pollination takes place under the water.

Order 5. =Alismaceæ.= The regular, _hypogynous_ flowers are in some species unisexual by the suppression of either andrœcium or gynœceum; they have a 6-merous perianth, _generally_ differentiated into 3 sepals and 3 petals; generally 6 _stamens in the outer whorl_ (by the division of the 3; Fig. 282) and often several 3-merous whorls inside these, and 6–∞ _free_ carpels arranged cyclically or spirally. Fruit a syncarp.--Marsh- or water-plants with radical leaves and long-stalked inflorescences.

=A.= _Butomeæ. Follicles with many seeds, which are borne on nearly the whole of the inner surface of the cyclic carpels_ (as in Nymphæaceæ). Embryo _straight_.--_Butomus_ (Flowering Rush, Fig. 282), has an umbel (generally composed of 3 helicoid cymes). _S_ 3, _P_ 3, stamens 9 (6 + 3, _i.e._ the outer whorl doubled), _G_ 3 + 3. ~_B. umbellatus_; creeping rhizome with triangular Iris-like leaves.--_Hydrocleis. Limnocharis._~

=B.= _Alismeæ._ Fruit achenes. Latex common (in the intercellular spaces). The flowers are arranged most frequently in single or compound whorls. Embryo _curved_, horse-shoe shaped.--_Alisma_ has _S_ 3, _P_ 3, _A_ 6 (in 1 whorl, grouped in pairs, _i.e._ doubled in front of the sepals), and 1 _whorl_ of 1-seeded achenes on a flat receptacle. The leaves are most frequently radicle, long-stalked; the lamina have curved longitudinal veins, and a richly branched venation. _A. plantago._--_Elisma_ (_E. natans_) has epitropous (turned inwards) ovules, whilst the ovules of _Alisma_, _Sagittaria_ and others are apotropous (turned outwards).--_Echinodorus_ (_E. ranunculoides_) has a convex receptacle, carpels many, united and capitate. _Damasonium_.--_Sagittaria_ (Arrow-head) has _monœcious_ flowers, several whorls of stamens and _spirally-arranged achenes_ on a very convex receptacle. ~_S. sagittifolia_ reproduces by tuberous buds formed at the end of long, submerged branches. The leaves, in deep and rapidly running water, are long and strap-shaped, but in the air arrow-shaped.~

Honey is secreted in the flower and pollination effected
by insects. _Alisma plantago_ has 12 nectaries. The
submerged flowers of _Elisma natans_ remain closed and are
self-pollinated. _Butomus_ has protandrous flowers. There are
about 50 species, which mostly grow outside the Tropics.--Uses
insignificant. The rhizome of some is farinaceous.

Order 6. =Hydrocharitaceæ.= This order differs chiefly from the preceding in its _epigynous_ flowers. These are in general unisexual (_diœcious_), and surrounded by a 2-leaved or bipartite _spathe_; they are 3-merous in all whorls, but the number of whorls is generally greater than 5, sometimes even indefinite. The perianth is divided into _calyx_ and _corolla_. The ovary is _unilocular_ with parietal placentation, or more or less incompletely plurilocular. The fruit is berry-like, but usually ruptures irregularly when ripe. Embryo straight.--Most often submerged water-plants, leaves seldom floating on the surface. Axillary scales (_squamulæ intravaginales_).

_Hydrocharis._ Floating water-plants with round cordate leaves; S3, P3 (folded in the bud); ♂-flowers: 3 (-more) flowers inside each spathe; stamens 9–15, the most internal sterile. ♀-flowers solitary; three staminodes; ovary 6-locular, with many ovules attached to the septa; styles 6, short, bifid. [The petals of the ♀-flowers bear nectaries at the base. In this and the following genus the pollination is without doubt effected by insects.] ~_H. morsus ranæ_ (Frog-bit) has runners; it hibernates by means of special winter-buds.~--_Stratiotes_; floating plants with a rosette of linear, thick, stiff leaves with spiny margin, springing from a short stem, from which numerous roots descend into the mud. Inflorescence, perianth, and ovary nearly the same as in _Hydrocharis_, but the ♂-flower has 12 stamens in 3 whorls, of which the outer 6 are in 1 whorl (dédoublement), and inside the perianth in both flowers there are numerous (15–30) nectaries (staminodes?). _S. aloides_ (Water-soldier); in N. Eur. only ♀-plants.--~_Vallisneria spiralis_ is a tropical or sub-tropical plant, growing gregariously on the mud in fresh water. The leaves are grass-like, and the plants diœcious; the ♂-flowers are detached from the plant, and rise to the surface of the water, where they pollinate the ♀-flowers. These are borne on long, spirally-twisted peduncles which contract after pollination, so that the ♀-flower is again drawn under the water, and the fruits ripen deeply submerged.--_Elodea canadensis_ is also an entirely submerged plant. The leaves are arranged in whorls on a well-developed stem. Only ♀-plants in Europe (introduced about 1836 from N. Am). This plant spreads with great rapidity throughout the country, the reproduction being entirely vegetative. _Hydrilla_, _Halophila_, _Thalassia_, _Enhalus_.--In many of these genera the number of whorls in the flower is remarkably reduced; for example, in _Vallisneria_, in the ♂-flowers to 2: Pr 3, A (1-) 3, in the ♀ to 3: Pr 3, Staminodes 3, G 3.--About 40 species; Temp. and Trop.~

Family 2. =Glumifloræ.=

The _hypogynous_ flowers in the Juncaceæ are completely developed on the _pentacyclic, trimerous_ type, with _dry, scarious perianth_. Even in these the interior whorl of stamens becomes suppressed, and the ovary, which in _Juncus_ is trilocular with many ovules, becomes in _Luzula_ almost unilocular, but still with 3 ovules. The perianth in the Cyperaceæ and Gramineæ is reduced from hairs, in the first of these, to nothing, the flowers at the same time collecting more closely on the inflorescence (spike) supported by _dry_ bracts (_chaff_); the number of stamens is almost constantly 3; stigmas linear; the ovary has only 1 loculus with 1 ovule, and the fruit, which is a capsule in the Juncaceæ, becomes a nut or caryopsis.--The endosperm is large and floury, the embryo being placed at its lower extremity (Figs. 286 _B_, 291).--The plants belonging to this order, with the exception of a few tropical species, are annual or perennial herbs. The stems above ground are thin, and for the most part have long internodes, with linear, parallel-veined leaves which have long _sheaths_, and often a _ligule_, _i.e._ a membranous projection, arising transversely from the leaf at the junction of the sheath and blade. The underground stems are short or creeping rhizomes. The flowers are small and insignificant. Wind- or self-pollination.

Order 1. =Juncaceæ= (=Rushes=). The regular, hermaphrodite, hypogynous flowers have 3 + 3 brown, dry, free perianth-leaves projecting like a star during the opening of the flower; stamens 3 + 3 (seldom 3 + 0) and 3 carpels united into one gynœceum (Fig. 283); the ovary is 3- or 1-locular; there is as a rule 1 style, which becomes divided at the summit into 3 stigmas, often bearing branches twisted to the right (Fig. 283). _Fruit a capsule_ with loculicidal dehiscence. The embryo is an extremely small, ellipsoidal, cellular mass, without differentiation into the external organs.

_Juncus_ (Rush) has glabrous foliage-leaves, generally cylindrical, rarely flat; the edges of the leaf-sheath are free (“_open_” leaf-sheaths) and cover one another. The capsule, 1- or 3-locular, with _many_ seeds--_Luzula_ (Wood-Rush) has flat, grass-like leaves with ciliated edges; the edges of the leaf-sheath are united (“_closed_” leaf-sheath). The capsule unilocular and _3-seeded_.--_Prionium_: S. Africa; resembling a _Tacona_.

The _interior_ whorl of stamens, in some species, disappears
partially or entirely (_J. supinus_, _capitatus_,
_conglomerates_, etc.)