Part 34

USES. Comparatively few. The only important one is _Beta vulgaris_ (from the Mediterranean basin), with its different varieties, viz. Beet-root, Cattle-beet or Red-beet, Sugar-beet, and others. These are biennial, making in the first year a root which acts as a reservoir of reserve material, with a rosette of leaves, and in the second year using this material in the production of a long stem, leaves and flowers. The primary root has been developed by cultivation into a very thick and fleshy tap-root; its mode of increase in thickness deviates from that of other roots, concentric rings of vascular bundles being formed from a cambial ring developed outside the previous ring. In this way several rings of vascular bundles separated by medullary rays, alternating with rings of parenchyma, may be found in the root of a Beet. Besides _Beta vulgaris_, var. _hortensis_ (Beet-root), the following are also cultivated: var. _cicla_ (Leaf-beet, “Mangold,” or “Roman Spinach ”), _Spinacia oleracea_ and _Atriplex hortensis_ as Spinach; a form of the latter and of Spinach are grown as ornamental plants. The tubers of _Ullucus tuberosus_ are used as potatoes; _Chenopodium quinoa_, in Chili and Peru, is an important farinaceous plant. Soda is made from some (_Salsola kali_, _Chenopodina maritima_ and others). Aromatic properties are rare: _Chenopodium ambrosioides_ and _botrys_.

Order 4. =Batidaceæ.= _Batis maritima_, a bushy West Indian maritime plant.

Order 5. =Phytolaccaceæ.= The ☿ (sometimes unisexual), regular, sometimes slightly perigynous flowers are inconspicuous and have a single sepaloid or coloured 4–5-leaved perianth (generally united at the base); stamens either in 1 whorl in the spaces between the perianth-leaves or in 1 whorl opposite the perianth-leaves, or in 2, one of which alternates with these; but the number may be increased by the splitting of one or of both the whorls to as many as 10–15–20–25. _Carpels_ sometimes only one, sometimes _many_ (4–10) placed in a whorl, either free or united into a gynœceum with a corresponding number of loculi in the ovary; but in all cases _each carpel bears only its own style and 1 ovule_. The fruit is a _berry_ (or nut, capsule, or schizocarp).--Mostly herbs or herbaceous shrubs, with scattered, simple leaves without stipules (_Petiverieæ_; have stipules). Inflorescences, most frequently _racemes_ or spikes, which in some instances are apparently placed opposite to a leaf, being displaced by a more vigorous growth of the axillary bud. Embryo always bent.--_Petiveria_ has a straight embryo with rolled cotyledons.--_Phytolacca_, _Pircunia_, _Microtea_, _Seguieria_, _Rivina_ (Pr4, A4, G1; berry), and others.

The following plant is, with some doubt, placed near this order: _Thelygonum cynocrambe_; monœcious. ♂-flowers: perianth, 2-leaved; stamens indefinite. ♀-flowers: perianth-leaves united, 3-toothed; G1, style gynobasic. Fruit a drupe. An annual plant; Mediterranean. Branching anomalous.

About 90 species; in tropical and temperate countries, principally America and Africa.--The red juice in the fruits, especially of _Phytol. decandra_, is used for colouring wine.

Order 6. =Portulacaceæ= (=Portulacas=). The flowers are regular (except _Montia_), hypogynous (except _Portulaca_) and ☿. The diagram which applies to the majority of genera is that in Fig. 367, but with all the 5 stamens completely developed: it may be considered as the Chenopodiaceous diagram with the addition of 2 _bracteoles_ in the median line (_m-n_, these by some are considered as sepals), and with a petaloid perianth (usually designated “corolla”). The “petals” fall off very quickly, and are sometimes wanting. Most frequently 5 stamens, situated opposite the “petals,” but in other genera the number varies; _Montia_ has only 3 stamens (by suppression of the two anterior and lateral, Fig. 367), others again have more than 5, some a large and indefinite number. This may be explained partly by the appearance of a second whorl of stamens alternating with the first, and partly by the splitting (dédoublement) of the stamens. Gynœceum most frequently tricarpellate, ovary unilocular with 1–several basal ovules (sometimes on a branched placenta, as in certain _Caryophyllaceæ_). The fruit is a _capsule_, more rarely a nut.--The majority are annual herbaceous plants with scattered, entire leaves, often fleshy and smooth, with or without rudimentary stipules (dry, membranous, modified into hairs). Inflorescence cymose.

_Portulaca_ (Portulaca): flower, epigynous or semi-epigynous; fruit, a pyxidium. The stamens vary in number, and are most frequently placed in groups (in consequence of splitting) opposite the petals.--_Montia_: the corolla is slightly gamopetalous, but cleft on the posterior side (Fig. 367), and as a consequence of the larger size of the lateral petals, slightly zygomorphic; 3 stamens.--_Calandrinia_; _Talinum_; _Anacampseros_; _Claytonia_.

125 species; mostly in warm and temperate countries, especially the arid parts of S. Am. and the Cape. _Montia fontana_ (Blinks) is a native plant. _Portulaca oleracea_ is cultivated as a pot-herb in the south of Europe. A few species of _Portulaca_ and _Calandrinia_ are ornamental plants.

Order 7. =Nyctaginiaceæ.= The characteristic feature of this order is the _single_, regular, _united_, and often petaloid perianth, the lower part of which generally persists after flowering and embraces the fruit as a false pericarp. The upper portion is most frequently _valvate and folded_, or simply valvate in æstivation. The number of stamens varies. The free gynœceum is _unicarpellate_ and has 1 ovule. The fruit is a _nut_, but becomes a _false drupe_, since the lower persistent portion of the perianth becomes fleshy (as in _Neea_, where this fleshy part is almost always crowned by the upper persistent part of the perianth. In the majority of the Mirabileæ the lower part becomes the dry _anthocarp_, while the upper petaloid part falls away after flowering). Finally, a peculiar involucre is formed around the flowers by free or united floral-leaves.--The majority are herbs, some are trees (_Pisonia_, etc.); _Bougainvillea_ is a liane. The stems are often nodose and swollen at the nodes; the leaves are simple, penninerved, scattered, or opposite, without stipules. ~In some, the vascular bundles are scattered; stem anomalous.~

_Mirabilis_; the structure of the stem is abnormal. Dichasial branching with continuation from the second bracteole, thus forming unipared scorpioid cymes. The perianth is petaloid, funnel-shaped, and has a folded and twisted æstivation resembling that of the corolla of the _Convolvulaceæ_; the upper coloured portion falls off after the flowering. Outside, and alternating with it, is a 5-partite, sepaloid involucre of 5 spirally-placed floral-leaves.--_Oxybaphus_; the involucre envelops 1–3 dichasial flowers.--_Bougainvillea_; the involucre is rose-coloured, 3-leaved, and envelops 3 flowers (placed laterally; the terminal flower wanting). The leaves of the involucre in _Boerhaavia_, _Pisonia_, _Neea_, and others are reduced to teeth or scales.

157 species; mostly in tropical countries, and especially S. Am. Species of _Mirabilis_ (Am.) are ornamental plants. Theïn is found in _Neea theïfera_ Oersted (discovered by Lund in Lagoa Santa, Brazil), which may be used as a tea-plant.

Order 8. =Aizoaceæ.= Only 3 _whorls_ are found in the flower, which _alternate_ with one another when their leaves are equal in number. The first is sepaloid, the third one the carpels, and the intervening one is either uncleft, in which case it is developed as stamens, or it is divided into a large number of members which then all become stamens (arranged in groups), or the outermost ones become developed as petals. The fruit is most frequently a capsule with several loculi. Most of the species are herbs with thick, fleshy stems, and exstipulate leaves. The structure of the stem is usually anomalous.

=1.= AIZOIDEÆ have hypogynous or perigynous flowers with (4–) 5 perianth-leaves; stamens single, or (by splitting) in groups of 2–3, alternating with the perianth-leaves. The gynœceum (with 3–5 carpels) has 3–5 loculi in the ovary, and most frequently numerous ovules in each loculus, borne on the central placenta formed by the edges of the carpels. The fruit is a capsule. The inflorescences are dichasia and unipared scorpioid cymes.--_Aizoon_, _Mollugo_, _Sesuvium_, and others are herbs or bushes, most frequently hairy.

=2.= MESEMBRIANTHEMEÆ have semi- or wholly-epigynous flowers.--_Tetragonia._ The perianth is 4 (more rarely 3–5–6)-merous. Stamens single, or (by splitting) in groups alternating with the perianth-leaves. There is an indefinite number of carpels, and each loculus of the ovary contains _only_ 1 pendulous ovule. Fruit a nut or drupe. The flowers arise singly in the leaf-axils, with an accessory foliage-bud below them; in some instances there is also an accessory flower between this bud and the flower. Southern hemisphere, especially at the Cape; _T. expansa_, New Zealand Spinach, is a fleshy plant which is cultivated as a pot-herb (Japan, Austr., S. Am.).--_Mesembrianthemum_: the flowers are 5-merous; the numerous linear petals and the still more numerous stamens all arise by the splitting of 5 or 4 protuberances (primordia) alternating with the sepals. The ovary presents another characteristic peculiarity: the carpels alternating with the 5–4 stamens form an ovary (with several loculi) with the ovules at first borne, as in other cases, on the _inner_ corner of the inwardly-turned carpels; but during the subsequent development the whole ovary is so turned round that the placentæ become parietal and the ovules assume, apparently, a position very rarely met with in the vegetable kingdom: on the dorsal suture of the carpels. Shrubs or under-shrubs, more rarely herbs with fleshy stems and simple, entire, more frequently thick or triangular leaves, containing a quantity of water. The flowers open about noon, and are brightly coloured, generally red or red-violet, but odourless. The capsules dehisce in rainy weather. 300 species, mostly found at the Cape. Some are ornamental plants. _M. crystallinum_ (the Ice-plant) and others are covered with peculiar, bladder-like, sparkling hairs, the cell-sap of which contains salt--these serve as reservoirs of water.

Family 8. =Cactifloræ.=

The position of this family is very doubtful; but it seems in many respects to approach _Mesembrianthemum_. Some botanists place it near to the Ribesiaceæ; others, again, to the Passifloraceæ. Only 1 order.

Order =Cactaceæ= (=The Cacti=). The flower is epigynous, ☿, regular, and remarkable for its _acyclic_ structure; there are, for instance, a large number of spirally-placed sepals and petals, which gradually pass over into one another, and which in some species, to a certain extent, arise from the walls of the ovary as in _Nymphæa_ (Fig. 383 _A_, _B_). The petals are free; rotate, opening widely in _Opuntia_, _Pereskia_, and _Rhipsalis_; erect and united at their base into a shorter or longer tube in _Cereus_, _Epiphyllum_, _Mammillaria_, _Echinocactus_, _Melocactus_, and others (Fig. 369). _Stamens numerous_, attached to the base of the corolla; gynœceum formed of _many carpels_, with one style, dividing into a number of branches corresponding to the number of carpels; the ovary has _one loculus_ with _many parietal_ placentæ; the ovules are anatropous, on long and curved funicles. Fruit a berry with exendospermous seeds. The fruit-pulp is mainly derived from the funicles.--The external appearance of the Cactaceæ is very peculiar; _Pereskia_, which has thick and fleshy leaves (Fig. 368), deviates the least; foliage-leaves of the usual form are wanting in the other genera, or are usually very small, and quickly fall off and disappear (_Opuntia_), or are modified into thorns; the stem, without normal foliage-leaves,--so characteristic a feature in this order,--makes its appearance after the two normally developed cotyledons. The stems are fleshy, perennial, and may finally become woody. In some they are elongated, globose, pointed, and more or less dichotomously branched, _e.g._ in several of the _Rhipsalis_ species, which live mostly as epiphytes on trees; in others, elongated, branched, globose, or, most frequently, more or less angular (prismatic) or grooved and provided with wings, and either columnar and erect (as much as about 20 metres in height and 1 metre in circumference, as in _C. giganteus_ in New Mexico) or climbing by roots (_Cereus_ and _Rhipsalis_-species); in others again, compressed, more or less leaf-like, often with a ridge in the centre (winged), branched and jointed: _Epiphyllum_, _Phyllocactus_, _Opuntia_, some species of _Rhipsalis_; others are thick, short, spherical or ovoid, unbranched or only slightly branched, and either studded with prominent warts (_mammillæ_) each of which supports a tuft of thorns (Fig. 368 _A_; _Mammillaria_ and others) or with vertical ridges, separated by furrows (rows of mammillæ which have coalesced) in _Melocactus_, _Echinocactus_, _Echinopsis_ (Fig. 369); at the same time the ovary in some is embedded in the stem so that leaves or leaf-scars, with tufts of thorns in their axils, may be observed on the ovary just as on the stem.--The flattened shoots of the Cactaceæ are formed in various ways, either by the compression of cylindrical axes (_Opuntia_) or, as in _Melocactus_, etc., from winged stems in which all the wings are suppressed except two.

The thorns are produced directly from the growing points of the axillary buds, and are modified leaves. The axillary bud is united at its base with its subtending leaf, which as a rule is extremely rudimentary; and these together form a kind of leaf-cushion, larger in some genera than in others. This leaf-cushion attains its highest development in _Mammillaria_, in which it is a large, conical wart (see Fig. 368 _A_), bearing on its apex the tuft of thorns and rudimentary lamina.--The _seedlings_ have normal cotyledons and a fleshy hypocotyl.

All the species (1,000?) are American (one epiphytic species of _Rhipsalis_ is indigenous in S. Africa, Mauritius and Ceylon), especially from the tropical table-lands (Mexico, etc.). Some species, especially those without thorns, as _Rhipsalis_, are epiphytes. _Opuntia vulgaris_, the fruits of which are edible, is naturalized in the Mediterranean. The cochineal insect (_Coccus cacti_) lives on this and some closely allied species (_O. coccinellifera_, etc.), particularly in Mexico and the Canary Islands. Several are ornamental plants.

Family 9. =Polycarpicæ.=

The flowers _as a rule are_ ☿, _regular_ and _hypogynous_; however in some orders they are unisexual, _e.g._ in the Myristicaceæ, or zygomorphic (in Monkshood and Larkspur in the Ranunculaceæ); in the Lauraceæ, (Fig. 386) for example, perigynous, and in _Nymphæa_ (Fig. 383) even partially epigynous flowers are typical.--The flowers are acyclic in very many of the genera of the two first orders, if not completely so, at any rate in the numerous stamens and carpels, thus denoting an old type. It is a remarkable characteristic that in the majority of the orders the number 3 prevails in the calyx and corolla; the number 5 also occurs, but the number 2 is seldom met with. Most orders have a double perianth; chorisis does not occur, suppression is rare, and the parts of the flower are developed in acropetal succession. The most characteristic feature in the order is the _free, one-leaved_, as a rule _numerous carpels_ (apocarpous gynœceum). The number of carpels in some of the last mentioned orders dwindles down to 1 (_e.g._ the _Berberideæ_ and _Myristicaceæ_). The carpels in _Nymphæaceæ_ become united into _one pistil_ (syncarpous), a condition which we also find distributed among the other orders.

_Endosperm occurs in almost all_ the orders (except _e.g. Lauraceæ_). The nutritive tissue in _Cabombeæ_ and _Nymphæeæ_ is chiefly _perisperm_.

Order 1. =Ranunculaceæ.= Nearly all are _herbs_ (except _Clematis_). The leaves are scattered (except _Clematideæ_), they have a large sheath with broad base (no stipules), and are most frequently palminerved with palmate lobes. The flowers are hypogynous, with most frequently a well pronounced convex receptacle (Figs. 374 _B_, 380), ☿, regular (except _Delphinium_ and _Aconitum_); their structure varies very much; in some the leaves are verticillate, in others arranged spirally; in others, again, both modes of arrangement are found. It is a characteristic feature that the various series of leaves (especially calyx and corolla) are not so distinct or so sharply divided as is usual. The leaves of the perianth are free, imbricate (except _Clematideæ_); stamens _numerous_, with most frequently extrorse anthers; gynœceum _free_, _apocarpous_ (except _Nigella_ and partly _Helleborus_), with 1 or several ovules (Figs. 373, 378, 379) borne on the ventral suture. The fruit is either a nut or a follicle (_Actæa_ has berries). The seed has a _large, oil-containing_ endosperm and a small embryo (Fig. 374).

The main axis generally terminates in a flower, and the lateral axes branch in a cymose manner (Fig. 371). The flowers show the following differences in construction: VERTICILLATE (EUCYCLIC), _i.e._ constructed all through of alternating whorls: _Aquilegia_ (Fig. 370), _Xanthorhiza_, and sometimes _Eranthis_. SEMIVERTICILLATE (HEMICYCLIC) _i.e._ with sepals and petals in alternate whorls, and the others arranged spirally: _Ranunculus_ (Fig. 371), _Myosurus_, _Pæonia_ and several other genera entirely, or in certain species only. SPIRAL-FLOWERED (ACYCLIC) _i.e._ all the leaves are arranged spirally, so that sepals and petals do not alternate the one with the other, even though they are the same in number: _Adonis_ (Fig. 372), _Aconitum_, _Delphinium_-species, _Nigella_-species, _Helleborus_. The leaves of the calyx are in this instance arranged on a spiral of 2/5; those of the corolla on 2/5, 3/8, 5/13 or 8/21, and stamens and carpels likewise on higher fractions of the same series.

The genera _Caltha_, _Anemone_, _Thalictrum_ and _Clematis_ have a _single perianth_, which is most frequently petaloid; it is thus apparent that the sepals are petaloid, and the leaves, which in other genera have developed as petals, are in these instances stamens. The calyx is similarly petaloid in the genera _Helleborus_, _Eranthis_, _Nigella_, _Delphinium_ and _Aconitum_; but the petals are present in these instances in unusual (horn-like) forms, and almost entirely given up to the function of nectaries, a function they already possess in _Ranunculus_. According to a more recent theory the “honey-leaves” are transformed stamens, which have lost the function of reproduction; the perianth is then single, and most frequently petaloid. [Those leaves in the flowers of many Ranunculaceæ which bear nectaries are termed by Prantl honey-leaves, and comprise those leaf-structures of the flower whose essential function lies in the production of nectar, and which, independent of the differentiation of the perianth into calyx and corolla, are derived from the stamens by the loss of their reproductive functions. Clear transitional forms are found between the two series of the perianth (_e.g._ between the sepaloid and petaloid perianth-leaves of _Anemone japonica_, _A. decapetala_, _Trollius_-species) while transitional forms are never found between perianth-and honey-leaves (with the exception of _Aquilegia vulgaris_, var. _stellata_). In _Anemone_ and _Clematis_ the honey-leaves pass gradually into the stamens, and agree with the stamens in the other Ranunculaceæ in their arrangement, development, and scant system of veins (except _Nigella_). In _Delphinium_, sect. _Consolida_, the two honey-leaves placed in front of the unpaired perianth-leaf are united into one, as shown by the veins (twice three veins arranged symmetrically). The honey-leaves of _Aquilegia_, _Callianthemum_, and the majority of the _Ranunculus_-species serve by reason of their large circumference, as organs of attraction, and on this account are considered as petals by other authors.--The same position in the flower which the honey-leaves assume is found occupied by staminodes, without nectar, in some _Coptis_-species, in _Anemonopsis_, _Actæa_ sect. _Euactæa_, (_e.g. A. racemosa_), _Clematis_ sect. _Atragene_; in the last-named they closely surround the stamens, in _Actæa_ they are petaloid.--A perianth, sharply differentiated into calyx and corolla, and destitute of honey-leaves, is found in _Anemone_, sect. _Knowltonia_ (Cape),

_Adonis_, _Pæonia_.--The perianth of the Ranunculaceæ is considered by Prantl to be usually petaloid.--The nectaries arise in the Ranunculaceæ (1) on normal stamens (_Clematis_ sect. _Viorna_), (2) on the honey-leaves (this is generally the case), and (3) on the carpels (_Caltha_ and the majority of _Trollius_-species).--As the result of his researches upon the Ranunculaceæ, Prantl does not agree with the view advanced by Drude (Schenk, _Hand. d. Bot._ iii.) that the petals in general have proceeded from the metamorphosis of the stamens (_K_)].

The most primitive form of fruit is undoubtedly the pod formed by one carpel, on the edges of which (along the ventral suture) two rows of ovules are situated: Pæonieæ, Helleboreæ, Delphinieæ (Fig. 379). In a great many genera the number of ovules has been limited to _one_ perfect one, which is placed in the central plane under the united leaf-edges, and sometimes also some barren ovules above it (Fig. 373). The fruitlets in this case become achenes, and are present in much larger numbers than when there are follicles.

The following have FOLLICLES: _Pæonieæ_, _Helleboreæ_ (except _Actæa_) and _Delphinieæ_; ACHENES: _Ranunculeæ_, _Anemoneæ_ and _Clematideæ_.