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.

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.

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.

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 following have Follicles: Pæonieæ, Helleboreæ (except Actæa) and Delphinieæ; Achenes: Ranunculeæ, Anemoneæ and Clematideæ.

A. Follicles (Figs. 375, 379), with many ovules, situated in two rows along the ventral suture. Actæa has berries, Nigella has capsules of several loculi.

1. Pæonieæ, Peony Group. This has regular, acyclic flowers with a normal, most frequently 5-leaved, imbricate calyx; large, coloured petals, and introrse anthers. Slightly perigynous. Surrounding the base of the carpels a ring-like swelling of the receptacle (“disc”) is present, which is largest in P. moutan. The follicles are more or less fleshy or leathery. Mostly herbs, with pinnatisect or decompound leaves and large, solitary flowers; a gradual transition may be traced from the foliage-leaves to the petals. Pæonia; Hydrastis.

2. Helleboreæ, Hellebore Group. This has regular flowers with most frequently a coloured calyx. The petals (honey-leaves) are modified into nectaries; they may be horn-like, provided with a spur, or of a similarly unusual form, or they may be entirely absent. Anthers often extrorse.—Trollius (Globe-flower[36]). The flower is acyclic: many petaloid sepals, succeeding these, most frequently, several linear, dark yellow petals, which bear a naked nectary at the base; finally, many stamens and carpels arranged in a spiral (3/8, 8/21).—Caltha (Marsh-marigold, Figs. 375, 377); 5 (-7) yellow sepals, no petals. The foliage-leaves have a large amplexicaul sheath.—Helleborous (Hellebore) has pedate leaves. The flower is acyclic, with 5 large, regular, persistent, often petaloid sepals (2/5); small, horn-like petals (honey-leaves; most frequently 13, divergence 8/13) and generally few carpels (Fig. 374).—Coptis.—Isopyrum.—Eranthis (Winter Aconite), like Anemone, has a 3-leaved involucre and most frequently trimerous flowers, 6 large petaloid sepals, 6 petals (tubular honey-leaves), 6 oblique rows of stamens, 3–6 carpels. Aquilegia (Columbine, Fig. 376); the flower is entirely cyclic and has large spurs on all the 5 petals (funnel-shaped honey-leaves); S5 coloured, P5, A5 × (8–12), G5 in regular alternation (Figs. 376, 370); the innermost stamens are often staminodes (Fig. 370).—Nigella (Love-in-the-mist, Fig. 378) has 5 sepals and 8 small, two-lipped petals cleft at the apex (the nectary is covered by the under-lip; Fig. 378 C, D). The 5 carpels are more or less completely united; and a many-carpellate ovary with free styles is formed in some. Large air-chambers in the external wall of the ovary are formed in N. damascena (Fig. 378).—Actæa (Baneberry) has coloured sepals, either no petals or an indefinite number, and only 1 carpel. The fruit is a berry (or follicle).—Cimicifuga, Garidella, Xanthorhiza (S5, P5, A5 + 5, G5).

3. Delphinieæ, Larkspur Group. Zygomorphic flowers with coloured calyx; the 2 posterior petals (honey-leaves) are transformed into nectaries, the others are small or absent altogether.—Aconitum (Monkshood); 5 sepals, of which the posterior one (Fig. 379 A) is helmet-shaped; most frequently 8 petals (as in Fig. 372), of which the two posterior ones (honey-leaves) are developed into long-clawed nectaries (Fig. 379 A, k) enveloped by the helmet-like sepal; the others are small, or are to some extent suppressed. Stamens on a spiral of 3/8–5/13; generally 3 carpels. Perennial herbs.—Delphinium (Larkspur); very closely allied to Aconitum, but the anterior 4 petals are most frequently wanting, and the 2 posterior ones have each a spur, which is enclosed by the posterior sepal, the latter being also provided with a membranous spur. Stamens and carpels arranged on a spiral of 3/8, 5/13, 8/21. In D. ajacis and consolida there is apparently only 1 petal (by the fusion of 4) and 1 carpel.

B. Fruit achenes. Many carpels, each with only 1 ascending (Fig. 373 C), or pendulous (Fig. 373 D), perfect ovule; often also rudimentary ovules above it (Fig. 373 A, B). Fruit achenes.

4. Ranunculeæ, Buttercup Group, has double perianth. Myosurus and Adonis have pendulous ovules as in Anemoneæ (Fig. 373 D); Ranunculus, with Batrachium and Ficaria, erect ovules (Fig. 373 C) and downwardly-turned radicle.—Ranunculus. Most frequently S5, P5, many spirally-placed stamens and carpels (Figs. 371, 380). The petals (honey-leaves) have a nectary at the base, covered by a small scale. Batrachium, Water Ranunculus, deviates by the achenes being transversely wrinkled; dimorphic leaves. Ficaria has 3 sepals and 7–8 petals arranged in 2/5–3/8. F. ranunculoides (the only species) has tuberous roots, which spring from the base of the axillary buds, and together with these, serve as organs of reproduction. The embryo has only 1 cotyledon.—Myosurus (Mouse-tail) has small prolongations from the 5 sepals; 5 narrow petals which bear the nectaries near the apex; sometimes only 5 stamens, and an ultimately very long receptacle, with numerous spirally-arranged achenes (Fig. 381).—Adonis is acyclic (Fig. 372); most frequently 5 sepals with a divergence of 2/5, 8 petals of 3/8, indefinite stamens and carpels of 3/8 or 5/13. The corolla has no nectary.

5. Anemoneæ, Anemone Group, has a single perianth. (Pendulous ovules (Fig. 373 D), radicle turned upward).—Anemone has a single, petaloid, most frequently 5–6-leaved perianth, and beneath the flower most frequently an involucre of 3 leaves, placed close together in the form of a whorl. In A. nemorosa, ranunculoides, etc., the involucral leaves resemble foliage-leaves; in A. hepatica they are situated close under the perianth, and resemble sepals, and in the sub-genus Pulsatilla they stand between the foliage-leaves and floral-leaves. The style of Pulsatilla finally grows out in the form of a feather. The main axis of A. hepatica has unlimited growth (it is biaxial), and the flowers are borne laterally in the axils of the scale-leaves; in the others (uniaxial) the flower is terminal, and the rhizome becomes a sympodium after the first flowering.—Thalictrum (Meadow Rue) has no involucre; 4–5-leaved, greenish perianth. The receptacle is flat. The stamens are brightly-coloured and have long filaments; 1–5 accessory flowers may occur in the leaf-axils of the panicle-like inflorescence.

6. Clematideæ, Clematis Group. This differs from all the others in the valvate æstivation of the calyx and its opposite leaves. There are 4 (-several) petaloid sepals; petals are absent, or linear (Atragene). Ovule 1, pendulous. Achenes, often with prolonged, feathery style. The majority of the genera are shrubs, and climb by their sensitive, twining leaf-stalks.—Clematis; Atragene.

Order 2. Nymphæaceæ (Water Lilies). Water Plants; generally with large, floating leaves, and large solitary flowers; sepals 3–5, petals 3–∞, stamens 6–∞, carpels 3–∞. The flower is hypogynous, but in the Nymphæeæ different degrees of epigyny are found, and from this fact, as well as from the carpels being united into one pistil, the family forms a lateral offshoot from the Ranunculaceæ, with much greater modification. The seed often has an aril, and, in the majority, a farinaceous nutritive tissue, partly endosperm, partly perisperm (Fig. 383 C). The embryo has 2 thick cotyledons and a small hypocotyl; the plumule is well developed, with 2–4 leaves.

2. Nelumboneæ. The leaves are peltate, raised on long stalks high above the water. Large, hypogynous flowers (Fig. 382); sepals 4–5; petals numerous; stamens numerous; carpels several, distinct. The receptacle is very remarkable, being raised above the stamens, and developed into an inverted conical body on the apex of which the nut-like fruits are embedded in pits. Endosperm is wanting, but the embryo is large and has well developed cotyledons.—Nelumbo, 2 species. N. lutea (N. Am.); N. speciosa (E. Ind.) was sacred amongst the ancient Hindoos and Egyptians, (the Lotus flower); its seeds are used as food.

3. Nymphæeæ, Water Lily Group. The carpels are united into one, many-locular ovary, whose numerous ovules are situated on the surface of the partition walls (as in the Poppies); the stigma is sessile and radiating, the number of rays corresponding to the number of carpels (Fig. 383). The fruit is a spongy berry with many seeds, which have a large perisperm in addition to the endosperm (Fig. 383 C).

Sepals, petals, and stamens often pass gradually over the one into the other, the petals becoming narrower by degrees, and bearing anthers on each side of the apex, which gradually become larger anthers in proportion to the filament, until the perfect stamen is developed. The long-stalked leaves are floating, and most frequently cordate, elliptical, leathery, with a shiny surface, sometimes (as in Victoria regia and Euryale ferox) with strongly projecting thorny ribs on the lower surface. In the intercellular passages of the leaves are some peculiar, stellate cells.

Nuphar has 5 sepals, and an hypogynous flower. The petals, which are small, have a nectary on the back; the coloured inner side of the sepals functions as petals; the ovate gynœceum is quite free.—N. luteum is a native plant (Yellow Water-Lily), with, most frequently, 13 petals and 10–16 loculi in the ovary. The rhizome is horizontal, as much as 5–6 cm. in thickness, and bears on its under surface a number of roots, which on dying-off leave deep scars; the leaves are borne in spiral lines, and the flowers are solitary in certain leaf-axils. The construction of the rhizome is very peculiar; the vascular bundles are scattered and closed as in a monocotyledonous stem.

Nymphæa has 4 sepals, and the flower is more or less epigynous. Petals and stamens are inserted at different heights on the ovary to just beneath the stigma (Fig. 383). Nymphæa alba (White Water-Lily). Victoria regia from the Amazon, and Euryale ferox from Asia, have entirely epigynous flowers. The shield-like leaves of Victoria are as much as 2 metres in diameter, and the edge is bent up to a height of 5–14 cm.; the flowers are 20–40 cm. in diameter, and change in twenty-four hours from white to rose-red. A development of heat, as much as 14°C. above the temperature of the air, together with a strong formation of carbonic acid, has been observed during flowering.

Order 3. Ceratophyllaceæ. About 3 species. Aquatic plants, submerged, rootless; leaves cartilaginous, verticillate, dissected into repeatedly dichotomous branches which are finely toothed; only one of the leaves in a whorl supports a vegetative branch. The flowers are monœcious, axillary. Inside the 6–12 perianth-leaves are situated in the ♂-flower 10–20 stamens with thick connective, and in the ♀-flower a gynœceum formed by one carpel, with one orthotropous and pendulous ovule, which has only one integument. Fruit a nut, which, in some species, bears on each side a pointed horn, and at the apex a similar one, formed by the persistent style.—The embryo has an unusually well developed plumule with several whorls of leaves. The plant is rootless throughout its whole life.—Ceratophyllum (Horn-wort).