Part 33

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.

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.

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.

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.

=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._~

=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.

=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_).

=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.