Fig. 103.Fig. 103.—Types ofAphanocyclæ(Rhœdinæ).A, plant of blood-root,Sanguinaria(Papaveraceæ), × ⅓.B, a single flower, × 1.C, fruit, × ½.D, section of the seed.em.embryo, × 2.E, diagram of the flower.F, flower of Dutchman’s breeches,Dicentra(Fumariaceæ), × 1.G, group of three stamens of the same, × 2.H, one of the inner petals, × 2.I, fruit of celandine poppy,Stylophorum(Papaveraceæ), × ½.J, flower of mustard,Brassica(Cruciferæ), × 1.K, the same, with the petals removed, × 2.L, fruit of the same, × 1.
Fig. 103.—Types ofAphanocyclæ(Rhœdinæ).A, plant of blood-root,Sanguinaria(Papaveraceæ), × ⅓.B, a single flower, × 1.C, fruit, × ½.D, section of the seed.em.embryo, × 2.E, diagram of the flower.F, flower of Dutchman’s breeches,Dicentra(Fumariaceæ), × 1.G, group of three stamens of the same, × 2.H, one of the inner petals, × 2.I, fruit of celandine poppy,Stylophorum(Papaveraceæ), × ½.J, flower of mustard,Brassica(Cruciferæ), × 1.K, the same, with the petals removed, × 2.L, fruit of the same, × 1.
The second family, the fumitories (Fumariaceæ) are delicate, smooth plants, with curious flowers and compound leaves. The garden bleeding-heart (Dicentra spectabilis) and the pretty, wildDicentras(Fig. 103,F) are familiar to nearly every one.
Other examples are the mountain fringe (Adlumia), a climbing species, and several species ofCorydalis, differing mainly fromDicentrain having the corolla one-sided.
The mustard family (Cruciferæ) comprises by far the greater part of the order. The shepherd’s-purse, already studied, belongs here, and may be taken as a type of the family. There is great uniformity in all as regards the flowers, so that the classification is based mainly on differences in the fruit and seeds. Many of the most valuable garden vegetables, as well as a few more or less valuable wild plants, are members of the family, which, however, includes some troublesome weeds. Cabbages, turnips, radishes, with all their varieties, belong here, as well as numerous species of wild cresses. A few like the wall-flower (Cheiranthus) and stock (Matthiola) are cultivated for ornament.
The last family is the caper family (Capparideæ), represented by only a few not common plants. The type of the order isCapparis, whose pickled flower-buds constitute capers.
The fourth order (Cistifloræ) of theAphanocyclæis a very large one, but the majority of the sixteen families included in it are not represented within our limits. The flowers have the sepals and petals in fives, the stamens either the same or more numerous.
Fig. 104.Fig. 104.—Types ofAphanocyclæ(Cistifloræ).A, flower of wild blue violet,Viola(Violaceæ), × 1.B, the lower petal prolonged behind into a sac or spur, × 1.C, the stamens, × 2.D, pistil, × 2.E, a leaf, × ½.F, section of the ovary, × 2.G, the fruit, × 1.H, the same after it has opened, × 1.I, diagram of the flower.J, flower of mignonette,Reseda(Resedaceæ), × 2.K, a petal, × 3.L, cross-section of the ovary, × 3.M, fruit, × 1.N, plant of sundew,Drosera(Droseraceæ), × ½.O, a leaf that has captured a mosquito, × 2.P, flower of another species (D. filiformis), × 2.Q, cross-section of the ovary, × 4.
Fig. 104.—Types ofAphanocyclæ(Cistifloræ).A, flower of wild blue violet,Viola(Violaceæ), × 1.B, the lower petal prolonged behind into a sac or spur, × 1.C, the stamens, × 2.D, pistil, × 2.E, a leaf, × ½.F, section of the ovary, × 2.G, the fruit, × 1.H, the same after it has opened, × 1.I, diagram of the flower.J, flower of mignonette,Reseda(Resedaceæ), × 2.K, a petal, × 3.L, cross-section of the ovary, × 3.M, fruit, × 1.N, plant of sundew,Drosera(Droseraceæ), × ½.O, a leaf that has captured a mosquito, × 2.P, flower of another species (D. filiformis), × 2.Q, cross-section of the ovary, × 4.
Among the commoner members of the order are the mignonettes (Resedaceæ) and the violets (Violaceæ), of which the various wild and cultivated species are familiar plants (Fig. 104,A,M). The sundews (Droseraceæ) are most extraordinary plants, growing in boggy land over pretty muchthewhole world. They are represented in the United States by several species of sundew (Drosera), and the still more curious Venus’s-flytrap (Dionæa) of North Carolina. The leaves ofthe latter are sensitive, and composed of two parts which snap together like a steel trap. If an insect lights upon the leaf, and touches certain hairs upon its upper surface, the two parts snap together, holding the insect tightly. A digestive fluid is secreted by glands upon the inner surface of the leaf, and in a short time the captured insect is actually digested and absorbed by the leaves. The same process takes place in the sundew (Fig. 104,N) where, however, the mechanism is somewhat different. Here the tentacles, with which the leaf is studded, secrete a sticky fluid which holds any small insect that may light upon it. The tentacles now slowly bend inward and finally the edges of the leaf as well, until the captured insectis firmly held, when a digestive process, similar to that inDionœa, takes place. This curious habit is probably to be explained from the position where the plant grows, the roots being in water where there does not seem to be a sufficient supply of nitrogenous matter for the wants of the plant, which supplements the supply from the bodies of the captured insects.
Fig. 105.Fig. 105.—Types ofAphanocyclæ(Cistifloræ).A,B, leaves of the pitcher-plant,Sarracenia(Sarraceniaceæ).A, from the side;B, from in front, × ½.C, St. John’s-wort (Hypericum), × ½.D, a flower, × 1.E, the pistil, × 2.G, cross-section of the ovary, × 4.H, diagram of the flower.
Fig. 105.—Types ofAphanocyclæ(Cistifloræ).A,B, leaves of the pitcher-plant,Sarracenia(Sarraceniaceæ).A, from the side;B, from in front, × ½.C, St. John’s-wort (Hypericum), × ½.D, a flower, × 1.E, the pistil, × 2.G, cross-section of the ovary, × 4.H, diagram of the flower.
Similar in their habits, but differing much in appearance from the sundews, are the pitcher-plants (Sarraceniaceæ), of which one species (Sarracenia purpurea) is very common in peat bogs throughout the northern United States. In this species (Fig. 105,A,B), the leaves form a rosette, from the centre of which arises in early summer a tall stalk bearing a single, large, nodding, dark-reddish flower with a curious umbrella-shaped pistil. The leaf stalk is hollow and swollen, with a broad wing on one side, and the blade of the leaf forms a sort of hood at the top. The interior of the pitcher is covered above with stiff, downward-pointing hairs, while below it is very smooth. Insects readily enter the pitcher, but onattempting to get out, the smooth, slippery wall at the bottom, and the stiff, downward-directed hairs above, prevent their escape, and they fall into the fluid which fills the bottom of the cup and are drowned, the leaf absorbing the nitrogenous compounds given off during the process of decomposition. There are other species common in the southern states, and a California pitcher-plant (Darlingtonia) has a colored appendage at the mouth of the pitcher which serves to lure insects into the trap.
Another family of pitcher-plants (Nepentheæ) is found in the warmer parts of the old world, and some of them are occasionally cultivated in greenhouses. In these the pitchers are borne at the tips of the leaves attached to a long tendril.
Two other families of the order contain familiar native plants, the rock-rose family (Cistaceæ), and the St. John’s-worts (Hypericaceæ). The latter particularly are common plants, with numerous showy yellow flowers, the petals usually marked with black specks, and the leaves having clear dots scattered through them. The stamens are numerous, and often in several distinct groups (Fig. 105,C,D).
The last order of theAphanocyclæ(theColumniferæ) has three families, of which two, the mallows (Malvaceæ), and the lindens (Tiliaceæ), include well-known species. Of the former, the various species of mallows (Fig. 106,A) belonging to the genusMalvaare common, as well as some species ofHibiscus, including the showy swampHibiscusor rose-mallow (H. moscheutos), common in salt marshes and in the fresh-water marshes of the great lake region. The hollyhock and shrubbyAlthæaare familiar cultivated plants of this order, and the cotton-plant (Gossypium) also belongs here. In all of these the stamens are much branched, and united into a tube enclosing the style. Most of them are characterized also by the development of great quantities of a mucilaginous matter within their tissues.
The common basswood (Tilia) is the commonest representativeof the familyTiliaceæ(Fig. 106,G). The nearly related European linden, or lime-tree, is sometimes planted. Its leaves are ordinarily somewhat smaller than our native species, which it, however, closely resembles.
Fig. 106.Fig. 106.—Types ofAphanocyclæ(Columniferæ).A, flower and leaf of the common mallow,Malva(Malvaceæ), × ½.B, a flower bud, × 1.C, section of a flower, × 2.D, the fruit, × 2.E, section of one division of the fruit, with the enclosed seed, × 3.em.the embryo.F, diagram of the flower.G, leaf and inflorescence of the basswood,Tilia(Tiliaceæ), × ⅓.br.a bract.H, a single flower, × 1.I, group of stamens, with petal-like appendage (x), × 2.J, diagram of the flower.
Fig. 106.—Types ofAphanocyclæ(Columniferæ).A, flower and leaf of the common mallow,Malva(Malvaceæ), × ½.B, a flower bud, × 1.C, section of a flower, × 2.D, the fruit, × 2.E, section of one division of the fruit, with the enclosed seed, × 3.em.the embryo.F, diagram of the flower.G, leaf and inflorescence of the basswood,Tilia(Tiliaceæ), × ⅓.br.a bract.H, a single flower, × 1.I, group of stamens, with petal-like appendage (x), × 2.J, diagram of the flower.
The fourth group of theChoripetalæis theEucyclæ. The flowers most commonly have the parts in fives, and the stamens are never more than twice as many as the sepals. The carpels are usually more or less completely united into a compound pistil. There are four orders, comprising twenty-five families.
Fig. 107.Fig. 107.—Types ofEucyclæ(Gruinales).A, wild crane’s-billGeranium(Geraniaceæ), × ½.B, a petal, × 1.C, the young fruit, the styles united in a column, × ½.D, the ripe fruit, the styles separating to discharge the seeds, × ½.E, section of a seed, × 2.F, wild flax.Linum(Linaceæ), × ½.G, a single flower, × 2.H, cross-section of the young fruit, × 3.I, flower.J, leaf of wood-sorrel,Oxalis(Oxalideæ), × 1.K, the stamens and pistil, × 2.L, flower of jewel-weed,Impatiens(Balsamineæ), × 1.M, the same, with the parts separated.p, petals.s, sepals.an.stamens.gy.pistil.N, fruit, × 1.O, the same, opening.P, a seed, × 2.
Fig. 107.—Types ofEucyclæ(Gruinales).A, wild crane’s-billGeranium(Geraniaceæ), × ½.B, a petal, × 1.C, the young fruit, the styles united in a column, × ½.D, the ripe fruit, the styles separating to discharge the seeds, × ½.E, section of a seed, × 2.F, wild flax.Linum(Linaceæ), × ½.G, a single flower, × 2.H, cross-section of the young fruit, × 3.I, flower.J, leaf of wood-sorrel,Oxalis(Oxalideæ), × 1.K, the stamens and pistil, × 2.L, flower of jewel-weed,Impatiens(Balsamineæ), × 1.M, the same, with the parts separated.p, petals.s, sepals.an.stamens.gy.pistil.N, fruit, × 1.O, the same, opening.P, a seed, × 2.
The first order (Gruinales) includes six families, consisting for the most part of plants with conspicuous flowers. Here belong the geraniums (Fig. 107,A), represented by the wild geraniums and crane’s-bill, and the very showy geraniums(Pelargonium) of the gardens. The nasturtiums (Tropæolum) represent another family, mostly tropical, and the wood-sorrels (Oxalis) (Fig. 107,I) are common, both wild and cultivated. The most useful member of the order is unquestionably the common flax (Linum), of which there are also several native species (Fig. 107,F). These are types of the flax family (Linaceæ). Linen is the product of the tough, fibrous inner bark ofL. usitatissimum, which has been cultivated for its fibre from time immemorial. The last family is the balsam family (Balsamineæ). The jewel-weed or touch-me-not (Impatiens), so called from the sensitive pods which spring open onbeing touched, is very common in moist ground everywhere (Fig. 107,L–P). The garden balsam, or lady’s slipper, is a related species (I. balsamina).
Fig. 108.Fig. 108.—Eucyclæ(Terebinthinæ,Æsculinæ).A, leaves and flowers of sugar-maple,Acer(Aceraceæ), × ½.B, a male flower, × 2.C, diagram of a perfect flower.D, fruit of the silver-maple, × ½.E, section across the seed, × 2.F, embryo removed from the seed, × 1.G, leaves and flowers of bladder-nut,Staphylea, (Sapindaceæ), × ½.H, section of a flower, × 2.I, diagram of the flower.J, flower of buckeye (Æsculus), × 1½.K, flower of smoke-tree,Rhus(Anacardiaceæ), × 3.L, the same, in section.
Fig. 108.—Eucyclæ(Terebinthinæ,Æsculinæ).A, leaves and flowers of sugar-maple,Acer(Aceraceæ), × ½.B, a male flower, × 2.C, diagram of a perfect flower.D, fruit of the silver-maple, × ½.E, section across the seed, × 2.F, embryo removed from the seed, × 1.G, leaves and flowers of bladder-nut,Staphylea, (Sapindaceæ), × ½.H, section of a flower, × 2.I, diagram of the flower.J, flower of buckeye (Æsculus), × 1½.K, flower of smoke-tree,Rhus(Anacardiaceæ), × 3.L, the same, in section.
The second order (Terebinthinæ) contains but few common plants. There are six families, mostly inhabitants of the warmer parts of the world. The best-known members of the order are the orange, lemon, citron, and their allies. Of our native plants the prickly ash (Zanthoxylum), and the various species of sumach (Rhus), are the best known. In the latter genus belong the poison ivy (R. toxicodendron) and the poison dogwood (R. venenata). The Venetian sumach or smoke-tree (R. Cotinus) is commonly planted for ornament.
The third order of theEucyclæ, theÆsculinæ, embraces six families, of which three, the horsechestnuts, etc. (Sapindaceæ), the maples (Aceraceæ), and the milkworts (Polygalaceæ), have several representatives in the northern United States. Of the first the buckeye (Æsculus) (Fig. 108,J) and the bladder-nut (Staphylea) (Fig. 108,G) are the commonest native genera, while the horsechestnut (Æsculus hippocastanum) is everywhere planted.
The various species of maple (Acer) are familiar examples of theAceraceæ(seeFig. 106,A,F).
The fourth and last order of theEucyclæ, theFrangulinæ, is composed mainly of plants with inconspicuous flowers, the stamens as many as the petals. Not infrequently they are diœcious, or in some, like the grape, some of the flowers may be unisexual while others are hermaphrodite (i.e.have both stamens and pistil). Among the commoner plants of the order may be mentioned the spindle-tree, or burning-bush, as it is sometimes called (Euonymus) (Fig. 109,A), and the climbing bitter-sweet (Celastrus) (Fig. 109,D), belonging to the familyCelastraceæ; the holly and black alder, species ofIlex, are examples of the familyAquifoliaceæ; the various species of grape (Vitis), the Virginia creeper (Ampelopsis quinquefolia), and one or two other cultivated species of the latter, represent the vine family (VitaceæorAmpelidæ), and the buckthorn (Rhamnus) is the type of theRhamnaceæ.
Fig. 109.Fig. 109.—Eucylæ(Frangulinæ),Tricoccæ.A, flowers of spindle-tree,Euonymus, (Celastraceæ), × 1.B, cross-section of the ovary, × 2.C, diagram of the flower.D, leaf and fruit of bitter-sweet (Celastrus), × ½.E, fruit opening and disclosing the seeds.F, section of a nearly ripe fruit, showing the seeds surrounded by the scarlet integument (aril).em.the embryo, × 1.G, flower of grape-vine,Vitis(Vitaceæ), × 2. The corolla has fallen off.H, vertical section of the pistil, × 2.I, nearly ripe fruits of the frost-grape, × 1.J, cross-section of young fruit, × 2.K, a spurge,Euphorbia(Euphorbiaceæ), × ½.L, single group of flowers, surrounded by the corolla-like involucre, × 3.M, section of the same, ♂, male flowers; ♀, female flowers.N, a single male flower, × 5.O, cross-section of ovary, × 6.P, a seed, × 2.Q, longitudinal section of the seed, × 3.em.embryo.
Fig. 109.—Eucylæ(Frangulinæ),Tricoccæ.A, flowers of spindle-tree,Euonymus, (Celastraceæ), × 1.B, cross-section of the ovary, × 2.C, diagram of the flower.D, leaf and fruit of bitter-sweet (Celastrus), × ½.E, fruit opening and disclosing the seeds.F, section of a nearly ripe fruit, showing the seeds surrounded by the scarlet integument (aril).em.the embryo, × 1.G, flower of grape-vine,Vitis(Vitaceæ), × 2. The corolla has fallen off.H, vertical section of the pistil, × 2.I, nearly ripe fruits of the frost-grape, × 1.J, cross-section of young fruit, × 2.K, a spurge,Euphorbia(Euphorbiaceæ), × ½.L, single group of flowers, surrounded by the corolla-like involucre, × 3.M, section of the same, ♂, male flowers; ♀, female flowers.N, a single male flower, × 5.O, cross-section of ovary, × 6.P, a seed, × 2.Q, longitudinal section of the seed, × 3.em.embryo.
The fifth group of theChoripetalæis a small one, comprising but a single order (Tricoccæ). The flowers are small and inconspicuous, though sometimes, as in someEuphorbiasand the showyPoinsettiaof the greenhouses, the leaves or bracts surrounding the inflorescence are conspicuously colored, giving the whole the appearance of a large, showy, single flower. In northern countries the plants are mostly small weeds, of which the various spurges orEuphorbiasare the most familiar. These plants (Fig. 109,K) have the small flowers surrounded by a cup-shaped involucre (L,M) so that the whole inflorescencelooks like a single flower. In the spurges, as in the other members of the order, the flowers are very simple, being often reduced to a single stamen or pistil (Fig. 109,M,N). The plants generally abound in a milky juice which is often poisonous. This juice in a number of tropical genera is the source of India-rubber. Some genera like the castor-bean (Ricinus) andCrotonare cultivated for their large, showy leaves.
The water starworts (Callitriche), not uncommon in stagnantwater, represent the familyCallitrichaceæ, and the box (Buxus) is the type of theBuxaceæ.
Fig. 110.Fig. 110.—Types ofCalycifloræ(Umbellifloræ).A, inflorescence of wild parsnip,Pastinaca(Umbelliferæ), × ½.B, single flower of the same, × 3.C, a leaf, showing the sheathing base, × ¼.D, a fruit, × 2.E, cross-section ofD.F, part of the inflorescence of spikenard,Aralia(Araliaceæ), × 1.G, a single flower of the same, × 3.H, the fruit, × 2.I, cross-section of theH.J, inflorescence of dogwood,Cornus(Corneæ). The cluster of flowers is surrounded by four white bracts (b), × ⅓.K, a single flower of the same, × 2.L, diagram of the flower.M, young fruit of another species (Cornus stolonifera) (red osier), × 2.N, cross-section ofM.
Fig. 110.—Types ofCalycifloræ(Umbellifloræ).A, inflorescence of wild parsnip,Pastinaca(Umbelliferæ), × ½.B, single flower of the same, × 3.C, a leaf, showing the sheathing base, × ¼.D, a fruit, × 2.E, cross-section ofD.F, part of the inflorescence of spikenard,Aralia(Araliaceæ), × 1.G, a single flower of the same, × 3.H, the fruit, × 2.I, cross-section of theH.J, inflorescence of dogwood,Cornus(Corneæ). The cluster of flowers is surrounded by four white bracts (b), × ⅓.K, a single flower of the same, × 2.L, diagram of the flower.M, young fruit of another species (Cornus stolonifera) (red osier), × 2.N, cross-section ofM.
The last and highest group of theChoripetalæ, theCalycifloræ, embraces a very large assemblage of familiar plants, divided into eight orders and thirty-two families. With few exceptions, the floral axis grows up around the ovary, carrying the outer floral leaves above it, and the ovary appears at the bottom of a cup around whose edge the other parts of the flower are arranged. Sometimes, as in the fuchsia, the ovary is grown to the base of the cup or tube, and thus looks as if it were outside the flower. Such an ovary is said to be “inferior”in distinction from one that is entirely free from the tube, and thus is evidently within the flower. The latter is the so-called “superior” ovary. The carpels are usually united into a compound pistil, but may be separate, as in the stonecrop (Fig. 111,E), or strawberry (Fig. 114,C).
The first order of theCalycifloræ(Umbellifloræ) has the flowers small, and usually arranged in umbels,i.e.several stalked flowers growing from a common point. The ovary is inferior, and there is a nectar-secreting disc between the styles and the stamens. Of the three families, the umbel-worts orUmbelliferæis the commonest. The flowers are much alike in all (Fig. 110,A,B), and nearly all have large, compound leaves with broad, sheathing bases. The stems are generally hollow. So great is the uniformity of the flowers and plant, that the fruit (Fig. 110,D) is generally necessary before the plant can be certainly recognized. This is two-seeded in all, but differs very much in shape and in the development of oil channels, which secrete the peculiar oil that gives the characteristic taste to the fruits of such forms as caraway, coriander, etc. Some of them, like the wild parsnip, poison hemlock, etc., are violent poisons, while others like the carrot are perfectly wholesome.
The wild spikenard (Aralia) (Fig. 110,F), ginseng, and the true ivy (Hedera) are examples of theAraliaceæ, and the various species of dogwood (Cornus) (Fig. 110,J–N) represent the dogwood family (Corneæ).
The second order (Saxifraginæ) contains eight families, including a number of common wild and cultivated plants. The true saxifrages are represented by several wild and cultivated species ofSaxifraga, the little bishop’s cap or mitre-wort (Mitella) (Fig. 111,D), and others. The wild hydrangea (Fig. 111,F) and the showy garden species represent the familyHydrangeæ. In these some of the flowers are large and showy, but with neither stamens nor pistils (neutral), while the small, inconspicuous flowers of the central partof the inflorescence are perfect. In the garden varieties, all of the flowers are changed, by selection, into the showy, neutral ones. The syringa or mock orange (Philadelphus) (Fig. 111,I), the gooseberry, and currants (Ribes) (Fig. 111,A), and the stonecrop (Sedum) (Fig. 111,E) are types of the familiesPhiladelpheæ,Ribesieæ, andCrassulaceæ.
Fig. 111.Fig. 111.—Calycifloræ(Saxifraginæ):A, flowers and leaves of wild gooseberry,Ribes(Ribesieæ), × 1.B, vertical section of the flower, × 2.C, diagram of the flower.D, flower of bishop’s-cap,Mitella(Saxifragaceæ), × 3.E, flower of stonecrop,Sedum(Crassulaceæ), × 2.F, flowers and leaves of hydrangea (Hydrangeæ), × ½.n, neutral flower.G, unopened flower, × 2.H, the same, after the petals have fallen away.I, flower of syringa,Philadelphus(Philadelpheæ), × 1.J, diagram of the flower.
Fig. 111.—Calycifloræ(Saxifraginæ):A, flowers and leaves of wild gooseberry,Ribes(Ribesieæ), × 1.B, vertical section of the flower, × 2.C, diagram of the flower.D, flower of bishop’s-cap,Mitella(Saxifragaceæ), × 3.E, flower of stonecrop,Sedum(Crassulaceæ), × 2.F, flowers and leaves of hydrangea (Hydrangeæ), × ½.n, neutral flower.G, unopened flower, × 2.H, the same, after the petals have fallen away.I, flower of syringa,Philadelphus(Philadelpheæ), × 1.J, diagram of the flower.
The third order (Opuntieæ) has but a single family, the cacti (Cactaceæ). These are strictly American in their distribution, and inhabit especially the dry plains of the southwest, where they reach an extraordinary development. They are nearly or quite leafless, and the fleshy, cylindrical, or flattened stems are usually beset with stout spines. The flowers (Fig. 112,A) are often very showy, so that many species are cultivated for ornament and are familiar to every one. The beautiful night-blooming cereus, of which there are several species, is one of these. A few species of prickly-pear (Opuntia) occur as far north as New York, but most are confined to the hot, dry plains of the south and southwest.
Fig. 112.Fig. 112.—Calycifloræ,Opuntieæ(Passiflorinæ).A, flower of a cactus,Mamillaria(Cactaceæ) (from “Gray’s Structural Botany”).B, leaf and flower of a passion-flower,Passiflora(Passifloraceæ), × ½.t, a tendril.C, cross-section of the ovary, × 2.D, diagram of the flower.
Fig. 112.—Calycifloræ,Opuntieæ(Passiflorinæ).A, flower of a cactus,Mamillaria(Cactaceæ) (from “Gray’s Structural Botany”).B, leaf and flower of a passion-flower,Passiflora(Passifloraceæ), × ½.t, a tendril.C, cross-section of the ovary, × 2.D, diagram of the flower.
The fourth order (Passiflorinæ) are almost without exception tropical plants, only a very few extending into the southern United States. The type of the order is the passion-flower (Passiflora) (Fig. 112,B), whose numerous species are mostly inhabitants of tropical America, but a few reach into the United States. The only other members of the order likely to be met with by the student are the begonias, of which a great many are commonly cultivated as house plantson account of their fine foliage and flowers. The leaves are always one-sided, and the flowers monœcious.[13]Whether the begonias properly belong with thePassiflorinæhas been questioned.
Fig. 113.Fig. 113.—Calycifloræ(Myrtifloræ,Thymelinæ).A, flowering branch of moosewood,Dirca(Thymelæaceæ), × 1.B, a single flower, × 2.C, the same, laid open.D, a young flower of willow herb,Epilobium(Onagraceæ), × 1. The pistil (gy.) is not yet ready for pollination.E, an older flower, with receptive pistil.F, an unopened bud, × 1.G, cross-section of the ovary, × 4.H, a young fruit, × 1.I, diagram of the flower.J, flowering branch of water milfoil,Myriophyllum(Haloragidaceæ), × ½.K, a single leaf, × 1.L, female flowers of the same, × 2.M, the fruit, × 2.
Fig. 113.—Calycifloræ(Myrtifloræ,Thymelinæ).A, flowering branch of moosewood,Dirca(Thymelæaceæ), × 1.B, a single flower, × 2.C, the same, laid open.D, a young flower of willow herb,Epilobium(Onagraceæ), × 1. The pistil (gy.) is not yet ready for pollination.E, an older flower, with receptive pistil.F, an unopened bud, × 1.G, cross-section of the ovary, × 4.H, a young fruit, × 1.I, diagram of the flower.J, flowering branch of water milfoil,Myriophyllum(Haloragidaceæ), × ½.K, a single leaf, × 1.L, female flowers of the same, × 2.M, the fruit, × 2.
The fifth order (Myrtifloræ) have regular four-parted flowers with usually eight stamens, but sometimes, through branching of the stamens, these appear very numerous. The myrtle family, the members of which are all tropical or sub-tropical, gives name to the order. The true myrtle (Myrtus) is sometimes cultivated for its pretty glossy green leaves and white flowers, as is alsothe pomegranate whose brilliant, scarlet flowers are extremely ornamental. Cloves are the dried flower-buds of an East-Indian myrtaceous tree (Caryophyllus). In Australia the order includes the giant gum-trees (Eucalyptus), the largest of all known trees, exceeding in size even the giant trees of California.
Among the commonerMyrtifloræ, the majority belong to the two familiesOnagraceæandLythraceæ. The former includes the evening primroses (Œnothera), willow-herb (Epilobium) (Fig. 113,D), and fuchsia; the latter, the purple loosestrife (Lythrum) and swamp loosestrife (Nesæa). The water-milfoil (Myriophyllum) (Fig. 113,J) is an example of the familyHaloragidaceæ, and theRhexiasof the eastern United States represent with us the familyMelastomaceæ.
The sixth order of theCalycifloræis a small one (Thymelinæ), represented in the United States by very few species. The flowers are four-parted, the calyx resembling a corolla, which is usually absent. The commonest member of the order is the moosewood (Dirca) (Fig. 113,A), belonging to the first of the three families (Thymelæaceæ). Of the second family (Elæagnaceæ), the commonest example isShepherdia, a low shrub having the leaves covered with curious, scurfy hairs that give them a silvery appearance. The third family (Proteaceæ) has no familiar representatives.
The seventh order (Rosifloræ) includes many well-known plants, all of which may be united in one family (Rosaceæ), with several sub-families. The flowers are usually five-parted with from five to thirty stamens, and usually numerous, distinct carpels. In the apple and pear (Fig. 114,I), however, the carpels are more or less grown together; and in the cherry, peach, etc., there is but a single carpel giving rise to a single-seeded stone-fruit (drupe) (Fig. 114,E,H). In the strawberry (Fig. 114,A), rose (G), cinquefoil (Potentilla), etc., there are numerous distinct, one-seeded carpels, and inSpiræa(Fig. 114,F) there are five several-seeded carpels,forming as many dry pods when ripe. The so-called “berry” of the strawberry is really the much enlarged flower axis, or “receptacle,” in which the little one-seeded fruits are embedded, the latter being what are ordinarily called the seeds.
Fig. 114.Fig. 114.—Calycifloræ(Rosifloræ).A, inflorescence of strawberry (Fragaria), × ½.B, a single flower, × 1.C, section ofB.D, floral diagram.E, vertical section of a cherry-flower (Prunus), × 1.F, vertical section of the flower ofSpiræa, × 2.G, vertical section of the bud of a wild rose (Rosa), × 1.H, vertical section of the young fruit, × 1.I, section of the flower of an apple (Pyrus), × 1.J, floral diagram of apple.
Fig. 114.—Calycifloræ(Rosifloræ).A, inflorescence of strawberry (Fragaria), × ½.B, a single flower, × 1.C, section ofB.D, floral diagram.E, vertical section of a cherry-flower (Prunus), × 1.F, vertical section of the flower ofSpiræa, × 2.G, vertical section of the bud of a wild rose (Rosa), × 1.H, vertical section of the young fruit, × 1.I, section of the flower of an apple (Pyrus), × 1.J, floral diagram of apple.
From the examples given, it will be seen that the order includes not only some of the most ornamental, cultivated plants, but the majority of our best fruits. In addition to those already given, may be mentioned the raspberry, blackberry, quince, plum, and apricot.
Fig. 115.Fig. 115.—Calycifloræ(Leguminosæ).A, flowers and leaf of the common pea,Pisum(Papilionaceæ), × ½.t, tendril.st.stipules.B, the petals, separated and displayed, × 1.C, flower, with the calyx and corolla removed, × 1.D, a fruit divided lengthwise, × ½.E, the embryo, with one of the cotyledons removed, × 2.F, diagram of the flower.G, flower of red-bud,Cercis(Cæsalpinaceæ), × 2.H, the same, with calyx and corolla removed.I, inflorescence of the sensitive-brier,Schrankia(Mimosaceæ), × 1.J, a single flower, × 2.
Fig. 115.—Calycifloræ(Leguminosæ).A, flowers and leaf of the common pea,Pisum(Papilionaceæ), × ½.t, tendril.st.stipules.B, the petals, separated and displayed, × 1.C, flower, with the calyx and corolla removed, × 1.D, a fruit divided lengthwise, × ½.E, the embryo, with one of the cotyledons removed, × 2.F, diagram of the flower.G, flower of red-bud,Cercis(Cæsalpinaceæ), × 2.H, the same, with calyx and corolla removed.I, inflorescence of the sensitive-brier,Schrankia(Mimosaceæ), × 1.J, a single flower, × 2.
The last order of theCalycifloræand the highest of theChoripetalæis the orderLeguminosæ, of which the bean, pea, clover, and many other common plants are examples. In most of our common forms the flowers are peculiar in shape,one of the petals being larger than the others, and covering them in the bud. This petal is known as the standard. The two lateral petals are known as the wings, and the two lower and inner are generally grown together forming what is called the “keel” (Fig. 115,A,B). The stamens, ten in number, are sometimes all grown together into a tube, but generally the upper one is free from the others (Fig. 115,C). There is but one carpel which forms a pod with two valves when ripe (Fig. 115,D). The seeds are large, and the embryo fills the seed completely. From the peculiar form of the flower, they are known asPapilionaceæ(papilio, a butterfly). Many of thePapilionaceæare climbers, either having twining stems, as in the common beans, or else with part of the leaf changed into a tendril as in the pea (Fig. 115,A), vetch, etc. The leaves are usually compound.
Of the second family (Cæsalpineæ), mainly tropical, the honey locust (Gleditschia) and red-bud (Cercis) (Fig. 115,G) are the commonest examples. The flowers differ mainly from thePapilionaceæin being less perfectly papilionaceous, and the stamens are almost entirely distinct (Fig. 115,H). The last family (Mimosaceæ) is also mainly tropical. The acacias, sensitive-plant (Mimosa), and the sensitive-brier of the southern United States (Schrankia) (Fig. 115,I) represent this family. The flowers are quite different from the others of the order, being tubular and the petals united, thus resembling the flowers of theSympetalæ. The leaves ofMimosaandSchrankiaare extraordinarily sensitive, folding up if irritated.
TheSympetalæorGamopetalæare at once distinguished from theChoripetalæby having the petals more or less united, so that the corolla is to some extent tubular. In the last order of theChoripetalæwe found a few examples (Mimosaceæ) where the same thing is true, and these form a transition from theChoripetalæto theSympetalæ.
There are two great divisions,IsocarpæandAnisocarpæ. In the first the carpels are of the same number as the petals and sepals; in the second fewer. In both cases the carpels are completely united, forming a single, compound pistil. In theIsocarpæthere are usually twice as many stamens as petals, occasionally the same number.
There are three orders of theIsocarpæ, viz.,Bicornes,Primulinæ, andDiospyrinæ. The first is a large order with six families, including many very beautiful plants, and a few of some economic value. Of the six families, all but one (Epacrideæ) are represented in the United States. Of these thePyrolaceæincludes the pretty little pyrolas and prince’s-pine (Chimaphila) (Fig. 116,J); theMonotropeæhas as its commonest examples, the curious Indian-pipe (Monotropa uniflora), and pine-sap (M. hypopitys) (Fig. 116,L). These grow on decaying vegetable matter, and are quite devoid of chlorophyll, the former species being pure white throughout (hence a popular name, “ghost flower”); the latter is yellowish. The magnificent rhododendrons and azaleas (Fig. 116,F), and the mountain laurel (Kalmia) (Fig. 116,I), belong to theRhodoraceæ.The heath family (Ericaceæ), besides the true heaths (Erica,Calluna), includes the pretty trailing-arbutus or may-flower (Epigæa),Andromeda,Oxydendrum(Fig. 116,E), wintergreen (Gaultheria), etc. The last family is represented by the cranberry (Vaccinium) and huckleberry (Gaylussacia).
Fig. 116.Fig. 116.—Types ofIsocarpous sympetalæ(Bicornes).A, flowers, fruit, and leaves of huckleberry,Gaylussacia(Vaccinieæ), × 1.B, vertical section of the flower, × 3.C, a stamen:i, from in front;ii, from the side, × 4.D, cross-section of the young fruit, × 2.E, flower of sorrel-tree,Oxydendrum(Ericaceæ), × 2.F, flower of azalea (Rhododendron), × ½.G, cross-section of the ovary, × 3.H, diagram of the flower.I, flower of mountain laurel (Kalmia), × 1.J, prince’s-pine,Chimaphila(Pyrolaceæ), × ½.K, a single flower, × 1.L, plant of pine-sap,Monotropa, (Monotropeæ), × ½.M, section of a flower, × 1.
Fig. 116.—Types ofIsocarpous sympetalæ(Bicornes).A, flowers, fruit, and leaves of huckleberry,Gaylussacia(Vaccinieæ), × 1.B, vertical section of the flower, × 3.C, a stamen:i, from in front;ii, from the side, × 4.D, cross-section of the young fruit, × 2.E, flower of sorrel-tree,Oxydendrum(Ericaceæ), × 2.F, flower of azalea (Rhododendron), × ½.G, cross-section of the ovary, × 3.H, diagram of the flower.I, flower of mountain laurel (Kalmia), × 1.J, prince’s-pine,Chimaphila(Pyrolaceæ), × ½.K, a single flower, × 1.L, plant of pine-sap,Monotropa, (Monotropeæ), × ½.M, section of a flower, × 1.
The second order, the primroses (Primulinæ), is principally represented in the cooler parts of the world by the true primrose family (Primulaceæ), of which several familiar plants may be mentioned. The genusPrimulaincludes the European primrose and cowslip, as well as two or three small American species, and the commonly cultivated Chinese primrose.Other genera areDodecatheon, of which the beautiful shooting-star (D. Meadia) (Fig. 117,A) is the best known. Something like this isCyclamen, sometimes cultivated as a house plant. The moneywort (Lysimachia nummularia) (Fig. 117,D), as well as other species, also belongs here.
Fig. 117.Fig. 117.—Isocarpous sympetalæ(Primulinæ,Diospyrinæ).A, shooting-star,Dodecatheon(Primulaceæ), × ½.B, section of a flower, × 1.C, diagram of the flower.D, Moneywort,Lysimachia(Primulaceæ), × ½.E, a perfect flower of the persimmon,Diospyros(Ebenaceæ), × 1.F, the same, laid open: section of the young fruit, × 2.H, longitudinal section of a ripe seed, × 1.em.the embryo.I, fruit, × ½.
Fig. 117.—Isocarpous sympetalæ(Primulinæ,Diospyrinæ).A, shooting-star,Dodecatheon(Primulaceæ), × ½.B, section of a flower, × 1.C, diagram of the flower.D, Moneywort,Lysimachia(Primulaceæ), × ½.E, a perfect flower of the persimmon,Diospyros(Ebenaceæ), × 1.F, the same, laid open: section of the young fruit, × 2.H, longitudinal section of a ripe seed, × 1.em.the embryo.I, fruit, × ½.
The sea-rosemary (Statice) and one or two cultivated species of plumbago are the only members of the plumbago family (Plumbagineæ) likely to be met with. The remaining families of thePrimulinæare not represented by any common plants.
The third and last order of theIsocarpous sympetalæhas but a single common representative in the United States; viz., the persimmon (Diospyros) (Fig. 117,E). This belongs to the familyEbenaceæ, to which also belongs the ebonya member of the same genus as the persimmon, and found in Africa and Asia.
The second division of theSympetalæ(theAnisocarpæ) has usually but two or three carpels, never as many as the petals. The stamens are also never more than five, and very often one or more are abortive.
Fig. 118.Fig. 118.—Types ofAnisocarpous sympetalæ(Tubifloræ).A, flower and leaves of wild phlox (Polemoniaceæ), × ½.B, section of a flower, × 1.C, fruit, × 1.D, flower of blue valerian (Polemonium), × 1.E, flowers and leaf of water-leaf,Hydrophyllum(Hydrophyllaceæ), × ½.F, section of a flower, × 1.G, flower of wild morning-glory,Convolvulus(Convolvulaceæ), × ½. One of the bracts surrounding the calyx and part of the corolla are cut away.H, diagram of the flower.I, the fruit of a garden morning-glory, from which the outer wall has fallen, leaving only the inner membranous partitions, × 1.J, a seed, × 1.K, cross-section of a nearly ripe seed, showing the crumpled embryo, × 2.L, an embryo removed from a nearly ripe seed, and spread out; one of the cotyledons has been partially removed, × 1.
Fig. 118.—Types ofAnisocarpous sympetalæ(Tubifloræ).A, flower and leaves of wild phlox (Polemoniaceæ), × ½.B, section of a flower, × 1.C, fruit, × 1.D, flower of blue valerian (Polemonium), × 1.E, flowers and leaf of water-leaf,Hydrophyllum(Hydrophyllaceæ), × ½.F, section of a flower, × 1.G, flower of wild morning-glory,Convolvulus(Convolvulaceæ), × ½. One of the bracts surrounding the calyx and part of the corolla are cut away.H, diagram of the flower.I, the fruit of a garden morning-glory, from which the outer wall has fallen, leaving only the inner membranous partitions, × 1.J, a seed, × 1.K, cross-section of a nearly ripe seed, showing the crumpled embryo, × 2.L, an embryo removed from a nearly ripe seed, and spread out; one of the cotyledons has been partially removed, × 1.
The first order (Tubifloræ) has, as the name indicates, tubular flowers which show usually perfect, radial symmetry (Actinomorphism). There are five families, all represented by familiar plants. The first (Convolvulaceæ) has as its type the morning-glory (Convolvulus) (Fig. 118,G), and the nearlyrelatedIpomœasof the gardens. The curious dodder (Cuscuta), whose leafless, yellow stems are sometimes very conspicuous, twining over various plants, is a member of this family which has lost its chlorophyll through parasitic habits. The sweet potato (Batatas) is also a member of the morning-glory family. The numerous species, wild and cultivated, of phlox (Fig. 118,A), and the blue valerian (Polemonium) (Fig. 118,D), are examples of the familyPolemoniaceæ.