_H_, the five pistils, 1. _I_, longitudinal section of the fruit, 1. _J_, flower of larkspur (_Delphinium_), 1. _K_, the four petals and stamens, after the removal of the five colored and petal-like sepals, 1.]

The magnolia family (_Magnoliaceae_) has several common members, the most widely distributed being, perhaps, the tulip-tree (_Liriodendron_) (Fig. 100, _C_), much valued for its timber. Besides this there are several species of magnolia, the most northerly species being the sweet-bay (_Magnolia glauca_) of the Atlantic States, and the cuc.u.mber-tree (_M. ac.u.minata_); the great magnolia (_M. grandiflora_) is not hardy in the northern states.

The sweet-scented shrub (_Calycanthus_) (Fig. 100, _G_) is the only member of the family _Calycanthaceae_ found within our limits. It grows wild in the southern states, and is cultivated for its sweet-scented, dull, reddish flowers.

[Ill.u.s.tration: FIG. 100.--Types of _Aphanocyclae_ (_Polycarpae_). _A_, branch of papaw, _Asimina_ (_Anonaceae_), . _B_, section of the flower, 1. _C_, flower and leaf of tulip-tree, _Liriodendron_ (_Magnoliaceae_), ?. _D_, section of a flower, . _E_, a ripe fruit, 1. _F_, diagram of the flower. _G_, flower of the sweet-scented shrub, _Calycanthus_ (_Calycanthaceae_), ]

The barberry (_Berberis_) (Fig. 101, _A_) is the type of the family _Berberideae_, which also includes the curious mandrake or may-apple (_Podophyllum_) (Fig. 101, _D_), and the twin-leaf or rheumatism-root (_Jeffersonia_), whose curious seed vessel is shown in Figure 101, _G_. The fruit of the barberry and may-apple are edible, but the root of the latter is poisonous.

The curious woody twiner, moon-seed (_Menispermum_) (Fig. 101, _I_), is the sole example in the northern states of the family _Menispermeae_ to which it belongs. The flowers are dicious, and the pistillate flowers are succeeded by black fruits looking like grapes. The flattened, bony seed is curiously sculptured, and has the embryo curled up within it.

[Ill.u.s.tration: FIG. 101.--Types of _Aphanocyclae_ (_Polycarpae_). _A-H_, _Berberidaceae_. _A_, flower of barberry (_Berberis_), 2. _B_, the same in section. _C_, a stamen, showing the method of opening, 3.

_D_, flower of may-apple (_Podophyllum_), . _E_, section of the ovary of _D_, 1. _F_, diagram of the flower. _G_, ripe fruit of twin-leaf (_Jeffersonia_), opening by a lid, . _H_, section of seed, showing the embryo (_em._), 2. _I_, young leaf and cl.u.s.ter of male flowers of moon-seed, _Menispermum_ (_Menispermeae_), 1. _J_, a single male flower, 2. _K_, section of a female flower, 2. _L_, ripe seed, 1. _M_, section of _L_, showing the curved embryo.]

The last two families of the order, the laurel family (_Laurineae_) and the nutmeg family (_Myristicineae_) are mostly tropical plants, characterized by the fragrance of the bark, leaves, and fruit. The former is represented by the sa.s.safras and spice-bush, common throughout the eastern United States. The latter has no members within our borders, but is familiar to all through the common nutmeg, which is the seed of _Myristica fragrans_ of the East Indies. "Mace" is the "aril" or covering of the seed of the same plant.

The second order of the _Aphanocyclae_ comprises a number of aquatic plants, mostly of large size, and is known as the _Hydropeltidinae_.

The flowers and leaves are usually very large, the latter usually nearly round in outline, and frequently with the stalk inserted near the middle. The leaves of the perigone are numerous, and sometimes merge gradually into the stamens, as we find in the common white water-lily (_Castalia_).

[Ill.u.s.tration: FIG. 102.--Types of _Aphanocyclae_ (_Hydropeltidinae_).

_A_, yellow water-lily, _Nymphaea_ (_Nymphaeaceae_), . _B_, a leaf of the same, ?. _C_, freshly opened flower, with the large petal-like sepals removed, . _p_, petals. _an._ stamens. _st._ stigma. _D_, section of the ovary, 2. _E_, young fruit, . _F_, lotus, _Nelumbo_ (_Nelumbieae_). ?. _G_, a stamen, 1. _H_, the large receptacle, with the separate pistils sunk in its surface, . _I_, section of a single pistil, 2. _ov._ the ovule. _J_, upper part of a section through the stigma and ovule (_ov._), 4.]

There are three families, all represented within the United States.

The first (_Nelumbieae_) has but a single species, the yellow lotus or nelumbo (_Nelumbo lutea_), common in the waters of the west and southwest, but rare eastward (Fig. 101, _F_). In this flower, the end of the flower axis is much enlarged, looking like the rose of a watering-pot, and has the large, separate carpels embedded in its upper surface. When ripe, each forms a nut-like fruit which is edible.

There are but two species of _Nelumbo_ known, the second one (_N. speciosa_) being a native of southeastern Asia, and probably found in ancient times in Egypt, as it is represented frequently in the pictures and carvings of the ancient Egyptians. It differs mainly from our species in the color of its flowers which are red instead of yellow. It has recently been introduced into New Jersey where it has become well established in several localities.

The second family (_Cabombeae_) is also represented at the north by but one species, the water shield (_Brasenia_), not uncommon in marshes.

Its flowers are quite small, of a dull-purple color, and the leaves oval in outline and centrally peltate, _i.e._ the leaf stalk inserted in the centre. The whole plant is covered with a transparent gelatinous coat.

The third family (_Nymphaeaceae_) includes the common white water-lilies (_Castalia_) and the yellow water-lilies (_Nymphaea_) (Fig. 102, _A_).

In the latter the petals are small and inconspicuous (Fig. 102, _C_, _p_), but the sepals are large and showy. In this family the carpels, instead of being separate, are united into a large compound pistil.

The water-lilies reach their greatest perfection in the tropics, where they attain an enormous size, the white, blue, or red flowers of some species being thirty centimetres or more in diameter, and the leaves of the great _Victoria regia_ of the Amazon reaching two metres or more in width.

The third order of the _Aphanocyclae_ (_Rhadinae_ or _Cruciflorae_) comprises a number of common plants, princ.i.p.ally characterized by having the parts of the flowers in twos or fours, so that they are more or less distinctly cross-shaped, whence the name _Cruciflorae_.

There are four families, of which the first is the poppy family (_Papaveraceae_), including the poppies, eschscholtzias, Mexican or p.r.i.c.kly poppy (_Argemone_), etc., of the gardens, and the blood-root (_Sanguinaria_), celandine poppy (_Stylophorum_), and a few other wild plants (see Fig. 103, _A-I_). Most of the family have a colored juice (latex), which is white in the poppy, yellow in celandine and _Argemone_, and orange-red in the blood-root. From the latex of the opium poppy the opium of commerce is extracted.

[Ill.u.s.tration: FIG. 103.--Types of _Aphanocyclae_ (_Rhdinae_). _A_, plant of blood-root, _Sanguinaria_ (_Papaveraceae_), ?. _B_, a single flower, 1. _C_, fruit, . _D_, section of the seed. _em._ embryo, 2. _E_, diagram of the flower. _F_, flower of Dutchman's breeches, _Dicentra_ (_Fumariaceae_), 1. _G_, group of three stamens of the same, 2. _H_, one of the inner petals, 2. _I_, fruit of celandine poppy, _Stylophorum_ (_Papaveraceae_), . _J_, flower of mustard, _Bra.s.sica_ (_Cruciferae_), 1. _K_, the same, with the petals removed, 2. _L_, fruit of the same, 1.]

The second family, the fumitories (_Fumariaceae_) are delicate, smooth plants, with curious flowers and compound leaves. The garden bleeding-heart (_Dicentra spectabilis_) and the pretty, wild _Dicentras_ (Fig. 103, _F_) are familiar to nearly every one.

Other examples are the mountain fringe (_Adlumia_), a climbing species, and several species of _Corydalis_, differing mainly from _Dicentra_ in having the corolla one-sided.

The mustard family (_Cruciferae_) 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 cla.s.sification 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 (_Capparideae_), represented by only a few not common plants. The type of the order is _Capparis_, whose pickled flower-buds const.i.tute capers.

The fourth order (_Cistiflorae_) of the _Aphanocyclae_ is 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.

[Ill.u.s.tration: FIG. 104.--Types of _Aphanocyclae_ (_Cistiflorae_). _A_, flower of wild blue violet, _Viola_ (_Violaceae_), 1. _B_, the lower petal prolonged behind into a sac or spur, 1. _C_, the stamens, 2.

_D_, pistil, 2. _E_, a leaf, . _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_ (_Resedaceae_), 2. _K_, a petal, 3. _L_, cross-section of the ovary, 3. _M_, fruit, 1. _N_, plant of sundew, _Drosera_ (_Droseraceae_), . _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 (_Resedaceae_) and the violets (_Violaceae_), of which the various wild and cultivated species are familiar plants (Fig. 104, _A_, _M_). The sundews (_Droseraceae_) are most extraordinary plants, growing in boggy land over pretty much the whole world. They are represented in the United States by several species of sundew (_Drosera_), and the still more curious Venus's-flytrap (_Dionaea_) of North Carolina. The leaves of the 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 insect is firmly held, when a digestive process, similar to that in _Diona_, 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.

[Ill.u.s.tration: FIG. 105.--Types of _Aphanocyclae_ (_Cistiflorae_). _A_, _B_, leaves of the pitcher-plant, _Sarracenia_ (_Sarraceniaceae_). _A_, from the side; _B_, from in front, . _C_, St. John's-wort (_Hyperic.u.m_), . _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 (_Sarraceniaceae_), 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 on attempting 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 (_Nepentheae_) 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 (_Cistaceae_), and the St. John's-worts (_Hypericaceae_). 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 the _Aphanocyclae_ (the _Columniferae_) has three families, of which two, the mallows (_Malvaceae_), and the lindens (_Tiliaceae_), include well-known species. Of the former, the various species of mallows (Fig. 106, _A_) belonging to the genus _Malva_ are common, as well as some species of _Hibiscus_, including the showy swamp _Hibiscus_ or rose-mallow (_H. moscheutos_), common in salt marshes and in the fresh-water marshes of the great lake region. The hollyhock and shrubby _Althaea_ are 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 quant.i.ties of a mucilaginous matter within their tissues.

The common ba.s.swood (_Tilia_) is the commonest representative of the family _Tiliaceae_ (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.

[Ill.u.s.tration: FIG. 106.--Types of _Aphanocyclae_ (_Columniferae_). _A_, flower and leaf of the common mallow, _Malva_ (_Malvaceae_), . _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 ba.s.swood, _Tilia_ (_Tiliaceae_), ?. _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 the _Choripetalae_ is the _Eucyclae_. 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.

[Ill.u.s.tration: FIG. 107.--Types of _Eucyclae_ (_Gruinales_). _A_, wild crane's-bill _Geranium_ (_Geraniaceae_), . _B_, a petal, 1. _C_, the young fruit, the styles united in a column, . _D_, the ripe fruit, the styles separating to discharge the seeds, . _E_, section of a seed, 2. _F_, wild flax. _Linum_ (_Linaceae_), . _G_, a single flower, 2. _H_, cross-section of the young fruit, 3. _I_, flower. _J_, leaf of wood-sorrel, _Oxalis_ (_Oxalideae_), 1. _K_, the stamens and pistil, 2. _L_, flower of jewel-weed, _Impatiens_ (_Balsamineae_), 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 (_Tropaeolum_) 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 (_Linaceae_). Linen is the product of the tough, fibrous inner bark of _L. usitatissimum_, which has been cultivated for its fibre from time immemorial. The last family is the balsam family (_Balsamineae_). The jewel-weed or touch-me-not (_Impatiens_), so called from the sensitive pods which spring open on being 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_).

[Ill.u.s.tration: FIG. 108.--_Eucyclae_ (_Terebinthinae_, _aesculinae_). _A_, leaves and flowers of sugar-maple, _Acer_ (_Aceraceae_), . _B_, a male flower, 2. _C_, diagram of a perfect flower. _D_, fruit of the silver-maple, . _E_, section across the seed, 2. _F_, embryo removed from the seed, 1. _G_, leaves and flowers of bladder-nut, _Staphylea_, (_Sapindaceae_), . _H_, section of a flower, 2. _I_, diagram of the flower. _J_, flower of buckeye (_aesculus_), 1. _K_, flower of smoke-tree, _Rhus_ (_Anacardiaceae_), 3. _L_, the same, in section.]

The second order (_Terebinthinae_) 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 p.r.i.c.kly 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 the _Eucyclae_, the _aesculinae_, embraces six families, of which three, the horsechestnuts, etc. (_Sapindaceae_), the maples (_Aceraceae_), and the milkworts (_Polygalaceae_), have several representatives in the northern United States. Of the first the buckeye (_aesculus_) (Fig. 108, _J_) and the bladder-nut (_Staphylea_) (Fig. 108, _G_) are the commonest native genera, while the horsechestnut (_aesculus hippocastanum_) is everywhere planted.

The various species of maple (_Acer_) are familiar examples of the _Aceraceae_ (see Fig. 106, _A_, _F_).

The fourth and last order of the _Eucyclae_, the _Frangulinae_, is composed mainly of plants with inconspicuous flowers, the stamens as many as the petals. Not infrequently they are dicious, or in some, like the grape, some of the flowers may be unis.e.xual 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 family _Celastraceae_; the holly and black alder, species of _Ilex_, are examples of the family _Aquifoliaceae_; 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 (_Vitaceae_ or _Ampelidae_), and the buckthorn (_Rhamnus_) is the type of the _Rhamnaceae_.

[Ill.u.s.tration: FIG. 109.--_Eucylae_ (_Frangulinae_), _Tricoccae_. _A_, flowers of spindle-tree, _Euonymus_, (_Celastraceae_), 1. _B_, cross-section of the ovary, 2. _C_, diagram of the flower. _D_, leaf and fruit of bitter-sweet (_Celastrus_), . _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_ (_Vitaceae_), 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_ (_Euphorbiaceae_), . _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 the _Choripetalae_ is a small one, comprising but a single order (_Tricoccae_). The flowers are small and inconspicuous, though sometimes, as in some _Euphorbias_ and the showy _Poinsettia_ of 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 or _Euphorbias_ are the most familiar. These plants (Fig. 109, _K_) have the small flowers surrounded by a cup-shaped involucre (_L_, _M_) so that the whole inflorescence looks 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_) and _Croton_ are cultivated for their large, showy leaves.

The water starworts (_Callitriche_), not uncommon in stagnant water, represent the family _Callitrichaceae_, and the box (_Buxus_) is the type of the _Buxaceae_.

[Ill.u.s.tration: FIG. 110.--Types of _Calyciflorae_ (_Umbelliflorae_).

_A_, inflorescence of wild parsnip, _Pastinaca_ (_Umbelliferae_), .

_B_, single flower of the same, 3. _C_, a leaf, showing the sheathing base, . _D_, a fruit, 2. _E_, cross-section of _D_.