Fig. 347–348.—Humulus lupulus: 347, twining stem; 348, branch with strobiles.
Cannabis sativa (Hemp, Figs. 350–353) is an East Indian herb, with palmilobed leaves, and differs from the Hop in being annual, erect, and in having its leaves opposite at the base and scattered above. The ♀-inflorescence is not cone-like as in the Hop, but the flowers are similar in construction. The main difference is to be found in the axillary shoot, which was suppressed in the Hop, and is in the Hemp developed into a leaf-bearing shoot which on each side bears only one ♀-flower, and in the fact that the bracts are not so strongly developed.
The “Hops” (the female inflorescences) are used in brewing, and medicinally on account of the yellow glands which contain lupulin. The Indian variety of Cannabis sativa contains an abundance of glandular hairs and resin. The withered inflorescences are used in medicine and are officinal. The bast of the stems of the Hemp is also used and the fat oil of the seeds. In Oriental countries the entire plant is used in the preparation of an intoxicating drink (haschisch), the narcotic material being found in the glandular hairs.
Fig. 349.—Humulus lupulus: fruit in longitudinal section.
Figs. 350–353.—Cannabis sativa: 350, ♂-plant; 351, ♂-flower; 352, ♀-flower, entire and in longitudinal section; 353, fruit in longitudinal section.
Family 6. Polygonifloræ.
This family is on one side closely allied to the Urticaceæ by its solitary, basal, vertical, and straight ovule, and by the conical ocrea which envelopes the younger leaves in the bud, similar characters being present in the Urticaceæ. On the other side it is related to the Curvembryæ. The flowers are small, often trimerous, regular and slightly perigynous (in Chloranthaceæ, if they properly belong to this family, and Houttuynia, more or less epigynous). Syncarps are present in some Piperaceæ, but the fruit is generally a single fruit, one-seeded berry, nut or drupe. The leaves are generally scattered.
Order 1. Polygonaceæ. The majority are herbaceous plants with round, often jointed stems, scattered leaves and ocrea, that is a membranous, tubular, ligular or stipular structure inside the base of the leaf, which clasps the stem and axillary bud; the edges of the lamina are rolled backwards in the bud. The flowers are regular, small, generally ☿, slightly perigynous, with inconspicuous, simple, green or white perianth of 5–6 free segments; stamens 5–9 (Fig. 354) sometimes arranged in two series; gynœceum 2–3 carpels, ovary unilocular with one basal, straight (orthotropous) ovule, 2–3 free styles. The fruit is a 2–3-angular nut; the embryo, with mealy endosperm, is straight or curved (Fig. 355 H), often unsymmetrical.—The inflorescences are compound, and generally branch from the axils of the bracteoles, so that the last partial-inflorescences become coiled, uniparous scorpioid cymes; in Polygonum the two bracteoles unite into a membranous tube; in Rheum and Rumex there is only one bracteole.
Fig. 354.—A Diagram of Rheum; B of Rumex; C of Polygonum fagopyrum; D of P. lapathifolium. The ovules are indicated inside the ovaries; bracts and bracteoles are not shown.
Rheum (Rhubarb, Fig. 354 A) has a 6-leaved, petaloid perianth (Pn 3 + 3) and 9 stamens (A 32 + 3). The 3-winged nut is not enclosed by the perianth.
Rumex (Dock, Fig. 354 B) has 6 stamens (A 32 + 0); the perianth is 6-leaved (Pr 3 + 3), green or red, and the triangular nut is enveloped by the 3 interior perianth-leaves, which point upwards and continue to grow after flowering. These perianth-leaves often have warts on their outer surface. The following are monœcious: R. acetosa and R. acetosella.
Polygonum (Knot-grass, Figs. 354 C, D; 355). The petaloid perianth is most frequently 5-merous (2/5 spiral); 5–8 stamens. The nut is triangular (Fig. 354 C, 355), or lenticular (Fig. 354 D). There are two whorls of stamens, the external with introrse, and the internal with extrorse anthers. The gynœceum is often bicarpellate (Fig. 354 D).
The flowers may be considered as constructed upon the monocotyledonous type. Pterostegia has a perfectly monocotyledonous flower with 5 trimerous whorls. Rheum likewise, but here the external staminal whorl is doubled (Fig. 254 A). Oxyria has a dimerous Rheum-flower (4-leaved perianth, 6 stamens, 2 stigmas). Rumex has a Rheum-flower with the suppression of the internal whorl of stamens (Fig. 354 B); Emex is a dimerous Rumex. Polygonum, to which Coccoloba, Muehlenbeckia and others are related, differs from Rheum chiefly in having one of the leaves, which in the latter takes part in the formation of the perianth, developed in this case into a bracteole (so that the perianth is reduced to five members), and several or all the stamens in the inner whorl become suppressed.—The perianth in Coccoloba and Muehlenbeckia is more or less perigynous and becomes fleshy, enclosing the fruit. Muehlenbeckia platyclada has flat branches with rudimentary leaves; sometimes branches with normal, arrow-shaped leaves are found. Atraphaxis.
Fig. 355.—Polygonum fagopyrum: A branch with flower and fruits (nat. size); B flower; C the same in longitudinal section; D anterior and posterior view of stamen; E gynœceum; F fruit (mag.); G fruit in longitudinal section; H transverse section, showing the curved cotyledons embedded in the endosperm; I the embryo.
Pollination. Rumex is wind-pollinated, the stigmas are therefore large and brush-like (indicated in Fig. 354 B). Rheum and Polygonum are insect-pollinated and have therefore capitate stigmas, etc.; honey-glands are situated at the base of the stamens (d, in Fig. 354 C, and n in Fig. 356); a few small-flowered Polygonum species are self-pollinated; Buckwheat (P. fagopyrum) is dimorphic and has long-styled and short-styled flowers (Fig. 356). Pol. bistorta is protandrous and homostyled.
About 750 species, most of which are found in the temperate regions of the Northern Hemisphere, some reaching as far as the snow line or into the Arctic regions (Oxyria, Kœnigia). Trees and shrubs are found in the Tropics: Coccoloba, Triplaris. Rheum is Central Asiatic.—The thick rhizomes of R. officinale (Rhubarb) are officinal. The rhizomes of the ordinarily cultivated species, R. undulatum and rhaponticum, are used in veterinary medicine. The following are cultivated as culinary plants for the sake of their leaves:—Rumex acetosa (Sorrel), R. patientia, R. scutatus, and Rheum undulatum (petioles). Several species of Polygonum (P. hydropiper and others) have a sharp, pungent taste. “Buckwheat” is the mealy fruit of Polygonum fagopyrum (Central Asia) and is of value as a farinaceous food. P. cuspidatum (P. sieboldi, Japan) is an ornamental plant.—Calligonum in sandy and stony deserts.
Fig. 356.—Flower of Polygonum fagopyrum in longitudinal section: 1, long-styled; 2, short-styled; a the anthers; st the stigmas; n nectary.
Order 2. Piperaceæ (Peppers). Shrubs or herbs, often with nodose, jointed stem; leaves simple, entire, often with curved veins; stipules wanting (Peperomia) or intrapetiolar and cap-like, often enclosing the terminal buds (Piper). The flowers in the group Pipereæ (Piper, Fig. 357, and Peperomia) are borne in spikes with fleshy axes (club-like), seldom in racemes, the outer ones are crowded and are ☿ or unisexual, always small, naked and without bracteoles; generally stamens 3 + 3, and gynœceum 3, but the number of the stamens may be reduced by suppression to 2, and the carpels to 1. The flowers are situated in the axils of the small, generally shield-like floral-leaves. The ovary is always unilocular and has one upright, orthotropous ovule. Fruit a berry or drupe. Both endosperm and perisperm are present, the latter being especially well developed (Fig. 359).
Piper; generally shrubs with scattered leaves, and terminal inflorescences which are crowded to one side by the development of the highest lateral bud, so that they are situated opposite the leaves (Fig. 357). Many species have stems with an abnormal anatomical structure.—Peperomia; chiefly succulent herbs, often epiphytes, with opposite or verticillate leaves having aqueous tissue on the upper side.
Fig. 357.—Piper nigrum: branch with fruit (½)
The group Saurureæ (considered by some as an order, and perhaps representing a more original type) has 3–4 carpels with many ovules. Lactoris stands the highest with regular 3-merous perianth, 3 + 3 stamens and 3 carpels, which are united at the base. Fruit a capsule with several seeds. (It has one species from the island of Juan Fernandez, and is also placed in an order of its own, Lactoridaceæ, allied to the Magnoliaceæ, through Drimys).—Saururus has naked flowers; most frequently 6 stamens, and 4 carpels, free or united at the base, each with 2-4 orthotropous ovules. Fruit, small berries.—Houttuynia; stamens situated a little upward on the ovaries; placentation parietal; capsule many-seeded.
About 1,000 species; entirely tropical, especially from South America and East India. They are found chiefly among the underwood in damp, shady places; some, which are fleshy (Peperomia), live as epiphytes on trees; a few climb by roots.—Uses. Several Piperaceæ are used medicinally and for spices on account of their pungent properties and the essential oils found in nearly all parts of the plant. The following are officinal: “Black-pepper” (the unripe, dried fruits) and “White-pepper” (the seeds of the ripe fruits) of Piper nigrum (climbing shrub, East Indian); “Cubeb” berries of P. cubeba (climbing shrub, Java). “Long-pepper” is the unripe inflorescence of P. longum, East India. The leaves of P. angustifolia (Matico) are officinal. The leaves of the Betelpepper (East India) are used together with the nuts of the Areca-palm to form the well-known East Indian intoxicating compound “Betel.” A good many others are also used.
Fig. 358.—Piper nigrum (Diagram). In addition to the bract there are two structures resembling bracteoles.
Fig. 359.—Piper nigrum: Fruit in longitudinal section, showing the endosperm, perisperm, and pericarp.
Order 3. Chloranthaceæ. (Chloranthus, Hedyosmum) have opposite leaves, with stipules more or less united at the base, and inferior “drupes.” Ovules pendulous. Only endosperm. About 33 species, Tropical.
Family 7. Curvembryæ.
The plants in this family have a curved ovule, and most frequently a kidney-shaped seed (generally provided with fine, cuticular, projecting warts, Fig. 362 B), with a curved, peripheral embryo enclosing the endosperm which is most frequently floury (Figs. 362 C, 365 H; for exceptions, see Fig. 366); the seeds in all cases are borne on a centrally-placed, and in most cases free, placenta (they are “basal” when there is only 1 ovule in the ovary, Fig. 364). The flower is regular, hypogynous or perigynous (Fig. 364) (only rarely epigynous) and usually 5-merous. The flower which is most complete has 5 whorls (S5, P5, A5+5, G2-3–5), as in some genera of the Caryophyllaceæ (Figs. 360, 361); but from this type it becomes reduced, the petals and stamens being suppressed, so that finally 5 perianth-leaves, 5 stamens (opposite the perianth-leaves), and 2 carpels (Fig. 361 F) only are present; for example, in certain genera of the Caryophyllaceæ, in the Chenopodiaceæ, Amarantaceæ, and others. When the number of stamens is increased to more than 5 in the whorl, it is always possible to show that some of the stamens have been divided. The number of the carpels and ovules also becomes reduced; in the highest there is a central placenta, not free in its early stages, with a large number of ovules; in those which are most reduced there is only a single ovule, which is placed centrally at the base of the ovary [Fig. 364]. Somewhat corresponding changes are found in the fruit, which is a many-seeded capsule in those which have many ovules, but a one-seeded nut where there is one ovule. In the most reduced forms the flowers are generally unisexual.—Similar features are also present in the vegetative parts. Almost all the species are herbaceous, the leaves are simple and most frequently without stipules. The structure of the stem, especially in Chenopodiaceæ, Amarantaceæ, Nyctaginiaceæ and others, often differs from that of the ordinary Dicotyledon. In the woody portion of the stem and root several rings are sometimes formed which resemble annual rings but which are formed by new cambium-rings arising outside the old ones which then cease to divide.
Order 1. Caryophyllaceæ. Herbaceous plants, with round, nodose stem; leaves opposite, slightly amplexicaul, simple, with sessile, undivided, entire lamina; stipules nearly always absent; the inflorescences are dichasia passing over into unipared scorpioid cymes. The flowers are regular, ☿ or unisexual, hypogynous or perigynous, 5-(or 4-) merous with 2–3–4–5 carpels; calyx persistent; corolla polypetalous. The ovary is unilocular (or originally, and sometimes also in the later stages, plurilocular below, e.g. Viscaria), with free styles and 1–several curved ovules on a central, free placenta. The fruit is a nut or a capsule opening apically with long or short valves (teeth, Fig. 362), equal to or double the carpels. For the seeds refer to the family. In Dianthus the embryo is straight.
The flowers which are most complete have Sn, Pn, An + n (obdiplostemonous), Gn where n = 5 (Figs. 360, 361 A) or 4 (Fig. 361 B); the carpels may be placed opposite to the sepals (Fig. 360) or opposite to the petals (Fig. 361 A, B). Without any change taking place in the position of the other whorls, the carpels are next found reduced to 2–3–4 (see the genera); their number may easily be recognised by that of the styles. This is the construction in the majority of the genera in the two first groups. Stellaria media differs considerably. It may have (a) the flower as described above, with G3; (b), the corolla only absent, or (c) only the petal-stamens (A5 + 0, Fig. 361 C), or (d) all these as well as some of the sepal-stamens. The same applies to Sagina, Alsine, Cerastium, and others, and, finally, a series of genera are formed, with certain conditions of reduction which have become constant, and by a gradual series of steps lead to the most reduced form, which has only 5 sepals and 5 (or even as far as only 1) sepal-stamens (Fig. 361 D, E, F).—The PETALS in the Alsineæ are often deeply bifid. The sepal-stamens are most frequently the longest, and bear nectaries at the base (Fig. 363 st). In the most complete forms the ovary has partition-walls in the lower portion (Fig. 360); these do not, however, reach to the top, and generally soon disappear. The ovules, when numerous, are situated on the placenta in as many double rows as there are carpels. In the number of ovules a reduction from many to 1 takes place (Fig. 361). A comparison proves that the “free, centrally placed” placenta is formed by the ventral portion of the carpels. The single basal ovule in Herniaria (Fig. 364), Scleranthus, and others, is also borne on the carpels.
The vegetative branching is characteristic. One of the leaves in a pair is formed before the other, and has a more vigorous axillary bud; these stronger leaves stand in a ¼-spiral, the fifth above the first one, and the branches are consequently arranged in the same manner. In the inflorescence, however, it is the upper or second bracteole (β) whose axillary bud (w in Fig. 361) is most advanced. The bud of the first bracteole (α) becomes sometimes entirely suppressed, or in some this bracteole itself is suppressed.
Fig. 360.—Diagram of Lychnis: α, β bracteoles.
Fig. 361.—A-F Diagrams of flowers of the Caryophyllaceæ: A Agrostemma; B Sagina; C Stellaria; D Corrigiola; E Paronychia; F Herniaria.
The most original type appears to be represented by the Alsineæ. From this form on one side the Sileneæ, adapted in a higher degree for insect-pollination, are developed, and on the other side the Paronychieæ, with various reductions.
1. Alsineæ, Stitchwort Group. Sepals free, and connected with them stellately expanded, slightly unguiculate (white or inodorous) petals; these, however, often become suppressed (Fig. 363). The fruit is a capsule.
Fig. 362.—Cerastium arvense: A fruit; B seed; C section of seed.
a. As many carpels as sepals (4 or 5). Cerastium (Chickweed). The petals are bifid. Capsule cylindrical, frequently curved at the top, and opening by 10 teeth (Fig. 362).—Malachium differs only in the 5-toothed capsule with bifid teeth.—Spergula (Spurry). The petals are not bifid, capsule 5-valved; seeds winged. The leaves are linear, and appear as if placed in large numbers in a whorl, a branch being situated in the axil of each with leaves placed very close together at its base; stipules membranous.—Sagina has Sn, Pn, An + n, or An, Gn, where n = 4 or 5. The corolla is often wanting.
b. 3 (rarely 2) carpels (Fig. 361 C). Stellaria (Stitchwort) has deeply cleft petals. The number of stamens varies (see above).—Arenaria has entire petals. (To this group belong Alsine, Moehringia, Halianthus, or Honckenya (Fig. 363), which differ from each other, especially in the form of the seed and number of the capsular valves.) Spergularia has membranous stipules, as in Spergula.—Holosteum.
Fig. 363.—Arenaria (Halianthus) peploides: ♀-(A) and ♂-flower (B, C).
2. Paronychieæ (Figs. 361 D, E, F; 364). Small, greenish plants. The leaves, in the majority, are opposite, with membranous stipules. The flowers are most frequently arranged in small dichasia; they are small and insignificant, perigynous (Fig. 364) or hypogynous. The corolla is in most cases wanting, and when present is very small; in general the calyx-stamens are developed, but the corolla-stamens may be represented by small scales (Fig. 364). Ovary most frequently with 1 ovule. Fruit, a nut, rarely a capsule; it is enclosed by the strongly perigynous floral axis (torus).
Scleranthus (Knapwell) is perigynous with bell-shaped torus; no corolla; corolla-stamens are wanting or rudimentary; some calyx-stamens may also be absent.—Corrigiola (Fig. 361 D); Illecebrum; Paronychia (Fig. 361 E); Herniaria (Figs. 361 F, 364).
3. Sileneæ, Pink or Carnation Group. This has a gamosepalous calyx and unguiculate, white or red, petals, with outgrowths (ligule, corona, paracorolla) at the throat of the corolla. These structures are not found in the other groups, and are merely outgrowths at the junction of the limb and claw. The corolla, stamens and ovary are frequently raised above the calyx, upon a lengthened internode (gynophore). The flower has S5, P5, A5 + 5; fruit a capsule with many seeds.
a. 5-(rarely 3–4) carpellate ovary.—Lychnis (Campion, Fig. 360). The corolla is longer than the calyx; corona present. The capsule is 10- or 5-toothed, completely 1-chambered or 5-chambered at the base,—the genus has been divided accordingly into several genera: Melandrium, Lychnis, Viscaria. Some species are unisexual by the abortion of stamens or carpels (L. vespertina, diurna). Agrostemma (A. githago, Corn-cockle, Fig. 361 A) has a long-toothed calyx, the teeth exceeding the corolla; corona absent; 5-toothed capsule.
Fig. 364.—Herniaria glabra: a1 flower; b1 longitudinal section through the flower; c1 stigma with two pollen-grains.
b. Tricarpellate.—Silene (Catch-fly). Six-toothed capsule; corona present in the majority.—Cucubalus has berry-like fruits which finally become dry but do not dehisce.
c. Bicarpellate (2 styles, 4-toothed capsule).—Dianthus (Pink); at the base of the calyx 1–several pairs of floral-leaves are situated; corona absent. The straight embryo is a peculiar exception.—Gypsophila has a campanulate, open calyx, 5-nerved, membranous between the nerves; corona absent; the flowers are generally small and numerous, in a large, paniculate dichasia.—Saponaria (Soapwort) has corona.
Pollination. Alsineæ has ordinary nectaries at the base of the calyx-stamens (Fig. 336): they are frequently protandrous but may often, in the absence of cross-pollination (in the less conspicuous species) pollinate themselves. Their open flowers are accessible to many kinds of insects (particularly flies and bees). Gynodiœcious flowers are found in several species, and the ☿-flowers are then generally more conspicuous than the ♀-flowers. That the ♀-flowers have descended from ☿-flowers is seen by the large staminodes found in them (Fig. 363). Arenaria peploides is diœcious (Fig. 363). The Sileneæ are as a rule adapted for pollination by insects with long probosces—especially butterflies,—and they are frequently protandrous, so that at first the calyx-stamens open, later on the corolla-stamens, then the stigmas expand. The honey is secreted by a ring-like nectary round the base of the ovary or by nectaries at the base of the stamens. Some only blossom and emit scent at night or in the evening (Lychnis vespertina, Silene nutans, Saponaria officinalis) and, like other night-flowers, are of a white or pale colour.
Distribution. 1,100 species, especially in temperate climates, fewer in the colder zone, less still in the Tropics. The Paronychieæ are especially found in dry, sandy fields.
Uses. “Soap-root” (with Saponin, forming a lather in water) from Saponaria officinalis was formerly officinal, and Gypsophila struthium. The seeds of Agrostemma githago are said to be poisonous.—The following are ornamental plants: species of Pinks (D. caryophyllus, garden Pink, often with double flowers; D. barbatus, plumarius, etc.). Lychnis, Gypsophila, Silene, Cerastium (C. tomentosum as edging for borders), Saponaria officinalis (often coronate).—Spergula arvensis is sometimes cultivated.
Order 2. Amarantaceæ. The flowers are essentially the same as in the Chenopodiaceæ and the extremely reduced Caryophyllaceæ (Fig. 361 F); they are regular, hypogynous, generally ☿, have 5 free (rarely slightly united) perianth-leaves; in front of these 5 stamens, which are often united at their base into a shorter or longer tube and have stipule-like teeth between them (the division Gomphreneæ has 2-locular anthers, each of which opens longitudinally); and a 2–3 carpellate gynœceum with one loculus and most frequently one, more rarely several ovules; the fruit is a nut, more rarely (in Celosia, Amarantus, Gomphrena) a capsule, dehiscing irregularly, or like a pyxidium. The characters which especially separate them from the allied orders are found in the perianth. The perianth-leaves are not green and herbaceous, but membranous, dry, and often coloured; they are frequently produced into a bristle or awn; they have also both subtending floral-leaves and 2 large bracteoles similar to the perianth; all these dry leaves persist without alteration after the withering of the flower.—The flowers are without scent. They are arranged in spike- or capitulum-like inflorescences; sometimes placed singly, sometimes aggregated in the panicle-like inflorescences; in others, on the contrary, in dichasia. The majority are herbs, some are shrubs. The leaves are scattered, or opposite, but always simple and without stipules; some are smooth, others hairy.
450 species; especially in the Tropics, principally S. Am. and E. Ind.: few are found outside these countries.—Only a few are used; some, chiefly E. Indian species, are cultivated as ornamental plants: Amaranthus (Fox-tail); Gomphrena globosa; Celosia cristata (Cock’s-comb) remarkable for its fasciated inflorescence; Alternanthera. Some are employed as culinary plants in the Tropics, and in a few of the E. Indian species the seeds are farinaceous, and used for food.
Order 3. Chenopodiaceæ. Generally herbaceous plants like the Caryophyllaceæ, but the leaves are arranged spirally (except Salicornia), and are simple, exstipulate; they are generally fleshy and like the stem “mealy,” that is, covered with small hairs, whose large spherical terminal cell readily falls away; otherwise they are seldom hairy. The inflorescences are generally flower-clusters borne in panicles. Bracteoles generally absent. Flowers generally unisexual: with the single exception of Beta the flowers are hypogynous; they are regular, small and inconspicuous, with single, green, 5-leaved, but more or less united perianth; 5 stamens opposite the perianth, and a 2–5-carpellate, unilocular ovary with 1 basal, curved ovule; but in some genera the number of the perianth-leaves and stamens is reduced to 3–2–1–0. The fruit is generally a nut,—thus this flower and fruit are the same as in the reduced Caryophyllaceæ (Fig. 361 F). The seed is similar to that generally found in the family (for exceptions see the genera).
The floral diagram most frequently present is the same as in Fig. 361 F. There is no indication of corolla or of corolla-stamens, which may be supposed to have belonged to the plant, but which are now entirely and completely suppressed. This order appears to have been an offshoot from the Caryophyllaceæ.—The perianth persists after the withering of the flower, and envelopes the nut; it is very variable, and, together with the position of the seed, the form of the embryo, the sex of the flowers, etc., gives the characters of the genera.
1. Chenopodieæ, Goosefoot Group (Fig. 365), has ☿ (or polygamous) flowers, with regular 5-parted perianth (C); the embryo is ring-like (H). The leaves have the ordinary flat forms.—Chenopodium (Goosefoot). The flower is hypogynous, and the fruit (which is compressed) perfectly free; Mulberry-like collections of fruits are formed in some species (sub-genus Blitum) by the perianth becoming finally fleshy and coloured.—Beta (Beet, Mangold, Fig. 365) differs from all genera in the perianth, which finally becomes cartilaginous, being epigynous (D). Small, most frequently 2–3-flowered clusters without bracteoles, situated in a long, interrupted axis (A, B); the flowers and fruits in each cluster are more or less united individually, and fall off together—they are commonly known as seeds (E, F). The seed lies horizontally.—Hablitzia (H. tamnoides).
Fig. 365.—Beta vulgaris.
Fig. 366.—Salsola soda: embryo.
2. Salsoleæ, Saltwort Group, has cylindrical or semi-cylindrical leaves. Perianth as in the preceding group; the fruit is most frequently compressed. The two first mentioned genera differ from most of the others in the order in having a spirally-coiled, and not a ring-like embryo, so that the endosperm is slight or wanting (Fig. 366). These plants are sometimes placed as a group by themselves, Spirolobeæ—in contradistinction to which the others are termed Cyclolobeæ.—Salsola (Saltwort); leaves subulate, with spiny tips; the flowers have 2 spinous bracteoles: during the ripening of the fruit a tough leathery wing is developed transversely to the back of the perianth.—Chenopodina deviates from Chenopodium chiefly in the embryo and want of endosperm.—Kochia has a somewhat similar perianth to Salsola, but a ring-like embryo; it differs from the others in being hairy.
3. Salicornieæ, Glasswort Group. Salicornia (Glasswort) has a very different appearance. The stems are succulent, jointed, and almost leafless; the leaves opposite, very small, sheath-like and connate; there is a depression in the axil of each leaf, in which a small 3-flowered dichasium without bracteoles is sunk; the flowers have a trimerous perianth, 1–2 stamens and 1 carpel. No endosperm. S. herbacea on clayey beaches.
4. Atripliceæ. This group has most frequently unisexual flowers; the ♂-flower has a 4–5 partite perianth, but the ♀-flower differs from it. Atriplex is monœcious or polygamous, the ♀-flower is naked, but has 2 large, herbaceous bracteoles which expand during the ripening of the fruit, and often become warted and fringed, enveloping the compressed nut. The section Dichospermum has two kinds of ♀-flowers, one like those just described, the other similar to the Chenopodium-flowers, which have been deprived of their stamens, and the fruits of which are depressed, not pressed together from the sides; some (e.g. A. hortensis) have even three kinds of nuts. All the flowers of Atriplex, which present vertical fruits, are accessory shoots, which stand beneath the ordinary flower-clusters, a rather singular relation.—Spinacia (Spinach) is diœcious; ♂-flower: perianth, 4 (-5); stamens, 4 (-5); ♀-flower: tubular, 2–4-partite perianth, hardening during the ripening of the fruit, and uniting with the compressed nut; in S. oleracea, it also forms thorns; 4 long stigmas.—Halimus has the 2 long bracteoles almost entirely united and ultimately adhering firmly to the fruit.
5. Baselleæ. A somewhat exceptional group with more or less perigynous flowers and 2 bracteoles. Basella, Boussingaultia, Ullucus. The perianth is sepaloid; ovary 1-ovuled. In Basella the perianth is fleshy, enveloping the nut, and the cotyledons are so rolled together that a tranverse cut divides them in two places (as in Spirolobeæ). Herbaceous climbing plants.
Pollination. Wind-and self-pollination, as far as is known; the insignificant flowers, devoid of honey, appear to exclude insect-pollination.—520 species. Most of them are annual (out of 26 native species only 5 are perennial); inhabiting salt-marshes and salt-steppes, and growing as weeds (most frequently on garden or field soil containing manure) in this country, especially species of Chenopodium and Atriplex. The majority are found outside the Tropics, and play a very important part, for example, in the Asiatic salt-steppes. They grow gregariously in large masses.
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.