Elementary Botany

Relation of Species, Genus, Family, Order, etc.

929. Species.—It is not necessary for one to be a botanist in order to recognize, during a stroll in the woods where the trillium is flowering, that there are many individual plants very like each other. They may vary in size, and the parts may differ a little in form. When the flowers first open they are usually white, and in age they generally become pinkish. In some individuals they are pinkish when they first open. Even with these variations, which are trifling in comparison with the points of close agreement, we recognize the individuals to be of the same kind, just as we recognize the corn plants, grown from the seed of an ear of corn, as of the same kind. Individuals of the same kind, in this sense, form a species. The white wake-robin, then, is a species.

But there are other trilliums which differ greatly from this one. The purple trillium (T. erectum) shown in fig. 495 is very different from it. So are a number of others. But the purple trillium is a species. It is made up of individuals variable, yet very like one another, more so than any one of them is like the white wake-robin.

930. Genus.—Yet if we study all parts of the plant, the perennial rootstock, the annual shoot, and the parts of the flower, we find a great resemblance. In this respect we find that there are several species which possess the same general characters. In other words, there is a relationship between these different species, a relationship which includes more than the individuals of one kind. It includes several kinds. Obviously, then, this is a relationship with broader limits, and of a higher grade, than that of the individuals of a species. The grade next higher than species we call genus. Trillium, then, is a genus. Briefly the characters of the genus trillium are as follows:

931. Genus trillium.—Perianth of six parts: sepals 3, herbaceous, persistent; petals colored. Stamens 6 (in two whorls), anthers opening inward. Ovary 3-loculed, 3-6-angled; stigmas 3, slender, spreading. Herbs with a stout perennial rootstock, with fleshy, scale-like leaves, from which the low annual shoot arises, bearing a terminal flower and 3 large netted-veined leaves in a whorl.

Note.—In speaking of the genus the present usage is to say trillium, but two words are usually employed in speaking of the species, as Trillium grandiflorum, T. erectum, etc.

932. Genus erythronium.—The yellow adder-tongue, or dogtooth violet (Erythronium americanum), shown in fig. 496, is quite different from any species of trillium. It differs more from any of the species of trillium than they do from each other. The perianth is of six parts, light yellow, often spotted near the base. Stamens are 6. The ovary is obovate, tapering at the base, 3-valved, seeds rather numerous, and the style is elongated. The flower stem, or scape, arises from a scaly bulb deep in the soil, and is sheathed by two elliptical-lanceolate, mottled leaves. The smaller plants have no flower and but one leaf, while the bulb is nearer the surface. Each year new bulbs are formed at the end of runners from a parent bulb. These runners penetrate each year deeper into the soil. The deeper bulbs bear the flower stems.

933. Genus lilium.—While the lily differs from either the trillium or erythronium, yet we recognize a relationship when we compare the perianth of six colored parts, the 6 stamens, and the 3-sided and long 3-loculed ovary.

934. Family Liliaceæ.—The relationship between genera, as between trillium, erythronium, and lilium, brings us to a still higher order of relationship, where the limits are broader than in the genus. Genera which are thus related make up the family. In the case of these genera the family has been named after the lily, and is the lily family, or Liliaceæ.

935. Order, class, group.—In like manner the lily family, the iris family, the amaryllis family, and others which show characters of close relationship are united into an order which has broader limits than the family. This order is the lily order, or order Liliales. The various orders unite to make up the class, and the classes unite to form a group.

936. Variations in usage of the terms class, order, etc.—Thus, according to the system of classification adopted by some, the angiosperms form a group. The group angiosperms is then divided into two classes, the monocotyledones and dicotyledones. (It should be remembered that all systematists do not agree in assigning the same grade and limits to the classes, subclasses, etc. For example, some treat of the angiosperms as a class, and the monocotyledons and dicotyledons as subclasses; while others would divide the monocotyledons and dicotyledons into classes, instead of treating each one as a class or as a subclass. Systematists differ also in usage as to the termination of the ordinal name; for example, some use the word Liliales for Liliifloræ, in writing of the order.)

937. Monocotyledones.—In the monocotyledons there is a single cotyledon on the embryo; the leaves are parallel-veined; the parts of the flower are usually in threes; endosperm is usually present in the seed; the vascular bundles are usually closed, and are scattered irregularly through the stem as shown by a cross-section of the stem of a palm (fig. 497), or by the arrangement of the bundles in the corn stem (fig. 57). Thus a single character is not sufficient to show relationship in the class (nor is it in orders, nor in many of the lower grades), but one must use the sum of several important characters.

938. Dicotyledones.—In the dicotyledons there are two cotyledons on the embryo; the venation of the leaves is reticulate; the endosperm is usually absent in the seed; the parts of the flower are frequently in fives; the vascular bundles of the stem are generally open and arranged in rings around the stem, as shown in the cross-section of the oak (fig. 497). There are exceptions to all the above characters, and the sum of the characters must be considered, just as in the case of the monocotyledons.

939. Taxonomy.—This grouping of plants into species, genera, families, etc., according to characters and relationships is classification, or taxonomy.

To take Trillium grandiflorum for example, its position in the system, if all the principal subdivisions should be included in the outline, would be indicated as follows:

• Group, Angiosperms.
• Class, Monocotyledones.
• Order, Liliales.
• Family, Liliaceæ.
• Genus, Trillium.
• Species, grandiflorum.

In the same way the position of the toothwort would be indicated as follows:

• Group, Angiosperms.
• Class, Dicotyledones.
• Order, Papaverales.
• Family, Cruciferæ.
• Genus, Dentaria.
• Species, diphylla.

But in giving the technical name of the plant only two of these names are used, the genus and species, so that for the toothwort we say Dentaria diphylla, and for the white wake-robin we say Trillium grandiflorum.

940. Kingdom and Subkingdom.—Organic beings form altogether two kingdoms, the Animal Kingdom and the Plant Kingdom. The Plant Kingdom is then divided into a number of subkingdoms as follows: 1st, Subkingdom Thallophyta, the thallus plants, including the Algæ and Fungi; 2d, Subkingdom Bryophyta, the moss-like plants, including the Liverworts and Mosses; 3d, Subkingdom Pteridophyta, the fern-like plants, including Ferns, Lycopods, Equisetum, Isoetes, etc.; 4th, Subkingdom Spermatophyta, the seed plants, including Gymnosperms and Angiosperms. Subkingdoms are divided into groups of lower order down to the classes. So there are subclasses, subfamilies or tribes, subgenera, and even subspecies. But taking the principal taxonomic divisions from the greater to the lesser rank, the order would be as follows:

• Plant Kingdom.
• Subkingdom, Spermatophyta.
• Group (not used in a definite sense).
• Class, Gymnospermæ.
• Order, Pinales.
• Family, Pinaceæ.
• Genus, Pinus.
• Species, strobus, or, in full,
• Pinus strobus, the white pine.

Group Angiospermæ.

I. CLASS MONOCOTYLEDONES.

941. Order Pandanales.—Aquatic or marsh plants. The cattail flags (Typha) and the bur-reeds (Sparganium), each representing a family. The name of the order is taken from the tropical genus Pandanus (the screw-pine often grown in greenhouses).

942. Order Naiadales.—Aquatic or marsh herbs. Three families are mentioned here.

The pondweed family (Naiadaceæ), named after one genus, Naias. The largest genus is Potamogeton, the species of which are known as pondweeds. Ruppia occidentalis occurs in saline ponds in Nebraska, and R. maritima along the seacoast and in saline districts in the interior.

The water-plantain family (Alismaceæ) includes the water-plantain (Alisma) and the arrow-leaves (Sagittaria).

The tape-grass family (Vallisneriaceæ) includes the tape-grass, or eel-grass (the curious Vallisneria spiralis).

943. Order Graminales.—Two families.

The grass family (Gramineæ), the grasses and grains.

The sedge family (Cyperaceæ), the sedges.

944. Order Palmales, with one family, Palmaceæ, includes the palms, abundant in the tropics and extending into Florida. Cultivated in greenhouses.

945. Order Arales.

The arum family (Araceæ). Flowers in a fleshy spadix. Examples: Indian turnip (Arisæma), sweet-flag (Acorus), skunk-cabbage (Spathyema).

The duckweed family (Lemnaceæ). (Examples: Lemna, Spirodela, Wolffia. See paragraphs 51-53.)

946. Order Xyridales, from the genus Xyris, the yellow-eyed grass family (Xyridaceæ). Species mostly tropical, but a few in North America. Other examples are the pipewort family (Eriocaulaceæ, example, Eriocaulon septangulare), the pineapple family (Bromeliaceæ, example, the pineapple cultivated in Florida); the Florida moss or hanging moss (Tillandsia usneoides); the spiderwort family (Commelinaceæ), including the spiderwort (Tradescantia, several species in North America); the pickerel-weed family (Pontederiaceæ), including the genus Pontederia in borders of ponds and streams.

947. Order Liliales.—Some of the families are as follows:

The rush family (Juncaceæ, example, Juncus), with many species, plants of usually swamp habit.

The lily family (Liliaceæ, examples: Lilium, Allium = Onion, Erythronium, Yucca).

The iris family (Iridaceæ, examples: Iris, the blue-flag, fleur-de-lis, etc.).

The lily-of-the-valley family (Convallariaceæ, examples: lily-of-the-valley, Trillium, etc.)

The amaryllis family (Amaryllidaceæ, examples: Narcissus, the daffodil; Cooperia, in southwestern United States).

948. Order Scitaminales.—This order includes the large showy cultivated Canna of the canna family.

949. Order Orchidales. Example, the orchid family (Orchidaceæ) with Cypripedium, Orchis, etc.

II. CLASS DICOTYLEDONES.

Series 1. CHORIPETALÆ. Petals wanting (Apetalæ, or Archichlamydæ of some authors), or present and distinct from one another (Polypetalæ, or Metachlamydæ).

950. Order Casuarinales, confined to tropical seacoasts (example, Casuarina).

951. Order Piperales includes the lizard’s-tail family (Saururaceæ), Saururus cernuus, lizard’s-tail, in the eastern United States.

952. Order Salicales.—Shrubs or trees, flowers in aments. Includes the willows and poplars (Salix and Populus of the willow family, Salicaceæ).

953. Order Myricales.—Shrubs or small trees. Includes the sweet-gale (Myrica gale) in wet places in northern United States and British North America, Myrica cerifera forming thickets on sand dunes along the Atlantic coast, and the sweet-fern (Comptonia peregrina = C. asplenifolia) in the eastern United States in dry soil of hillsides.

954. Order Leitneriales.—Shrubs or trees. Includes the cork-wood, Leitneria floridana (Leitneriaceæ).

955. Order Juglandales.—Trees, staminate flowers in aments. The walnut family (Juglandaceæ, examples: walnut, butternut, etc. Juglans; hickory, Hicoria = Carya).

956. Order Fagales.—Trees and shrubs. Flowers in aments, or the pistillate ones with an involucre which forms a cup in fruit, as in the acorn of the oak.

The birch family (Betulaceæ, examples: Betula, birch; Corylus, hazelnut; Alnus, alder, etc.).

The beech family (Fagaceæ = Cupuliferæ, examples: Fagus, beech; Castanea, chestnut; Quercus, oak).

957. Order Urticales.—Trees, shrubs, or herbs. Examples: the elm family (Ulmaceæ), the mulberry family (Moraceæ), and the nettle family (Urticaceæ).

958. Order Santalales, herbs or shrubs, mostly parasitic.

The mistletoe family (Loranthaceæ), with the American mistletoe (Phoradendron flavescens), parasitic on deciduous trees in the South Atlantic, Central, and Gulf States (N. J. to Ind. Ter.).

The sandalwood family (Santalaceæ, example, the bastard toad-flax, Comandra umbellata), widely distributed in North America.

959. Order Aristolochiales.—Herbs or vines with heart-shaped or kidney-shaped leaves. The birthwort family (Aristolochiaceæ, example, Aristolochia serpentaria, the Virginia snake-root, eastern United States; wild ginger, or heart-leaf, Asarum canadense, eastern North America.)

960. Order Polygonales.—Examples: the buckwheat family (Polygonaceæ), including buckwheat (Fagopyrum), and numerous species of Polygonum, known as smartweed, water-pepper, tear-thumb, bindweed, knotweed, prince’s-feather, etc.

961. Order Chenopodiales.—Herbs. There are several families; one of the largest is the goosefoot family (Chenopodiaceæ). The genus Chenopodium includes many species, known as goosefoot, lamb’s-quarters, etc. Here belong also the Russian thistle (Salsola tragus) and the saltwort (S. kali). The former is sometimes a troublesome weed in the central and western United States, naturalized from Europe. The latter occurs along the Atlantic coast on seabeaches. Atriplex occurs in salty or alkaline soil, also the glasswort (Salicornia herbacea), the bugseed (Corispermum). The pokeweed family (Phytolaccaceæ), the Amaranth family (Amaranthaceæ), the purslane family (Portulacaceæ, including the purslane or “pursley,” Portulaca oleracea, and the spring-beauty, Claytonia virginica), and the pink family (Caryophyllaceæ), belong here.

962. Order Ranales.—Herbs, shrubs, or trees. Examples are:

The water-lily family (Nymphæaceæ), with the yellow water-lily (Nymphæa advena = Nuphar advena) and the white water-lily (Castalia odorata = Nymphæa odorata).

The magnolia family (Magnoliaceæ), including the magnolias (Magnolia) and the tulip-tree (Liriodendron). The crowfoot family (Ranunculaceæ), with the buttercups, hepatica, clematis, etc.

963. Order Papaverales.—Mostly herbs. Examples are:

The poppy family (Papaveraceæ), including the opium or garden poppy (Papaver somniferum), the blood-root (Sanguinaria canadensis), the Dutchman’s-breeches (Bicuculla cucullaria = Dicentra cucullaria), squirrel’s-corn (Bicuculla canadensis = D. canadensis).

The mustard family (Cruciferæ), including the toothwort (Dentaria), shepherd’s-purse (Bursa bursa-pastoris = Capsella bursa-pastoris), the cabbage, turnip, etc.

964. Order Sarraceniales.—Insectivorous plants.

The pitcher-plant family (Sarraceniaceæ). Examples: Sarracenia purpurea, the pitcher-plant, in peat-bogs, northern and eastern North America.

The sundew family (Droseraceæ). Examples: Drosera rotundifolia, and other sundews.

965. Order Rosales.—Herbs, shrubs or trees. Seventeen families are given in the eastern United States. Examples:

The riverweed family (Podostemaceæ), containing the riverweed (Podostemon).

The saxifrage family (Saxifragaceæ), containing a number of species. Example, Saxifraga virginiensis.

The gooseberry family (Grossulariaceæ), including the wild and the cultivated gooseberry.

The witch-hazel family (Hamamelidaceæ), including the witch-hazel (Hamamelis), in eastern North America, and the sweet gum (Liquidambar styraciflua).

The plane-tree family (Platanaceæ), with the plane-tree, or buttonwood (Platanus occidentalis), eastern North America. (Other species occur in western United States.)

The rose family (Rosaceæ), including roses, spiræas, raspberries, strawberries, the shrubby cinquefoil (Dasiphora fruticosa), etc.

The apple family (Pomaceæ), including the apple, mountain-ash, pear, June-berry (or shadbush, also service-berry), the hawthorns (Cratægus).

The plum family (Drupaceæ), including the cherries, plums, peaches, etc.

The pea family (Papilionaceæ), including the pea, bean, clover, vetch, lupine, etc., a very large family.

966. Order Geraniales.—Herbs, shrubs, or trees. Nine families in the eastern United States. Examples:

The geranium family (Geraniaceæ), with the cranesbill (Geranium maculatum) and others.

The wood-sorrel family (Oxalidaceæ), with the wood-sorrel (Oxalis acetosella) and others.

The flax family (Linaceæ). Example, flax (Linum vulgaris).

The spurge family (Euphorbiaceæ). Plants with a milky juice, and curious, degenerate flowers. Examples: the castor-oil plant (Ricinus), the spurges (many species of Euphorbia).

967. Order Sapindales.—Mostly trees or shrubs. Twelve families in the eastern United States. Example:

The sumac family (Anacardiaceæ), containing the sumacs in the genus Rhus. Examples: the poison-ivy (R. radicans), a climbing vine, in thickets and along fences, in eastern United States. Sometimes trained over porches. The poison-oak (R. toxicodendron), a low shrub. Poison-sumac or poison-alder (R. vernix = R. venenata), sometimes called “thunderwood,” or dogwood, is a large shrub or small tree, very poisonous. The smoke-tree (Cotinus cotinoides) belongs to the same family, and is often planted as an ornamental tree. The maple family (Aceraceæ), including the maples (Acer).

The buckeye family (Hippocastanaceæ), including the horse-chestnut (Æsculus hippocastanum), much planted as a shade tree along streets. Also there are several species of buckeye in the same genus.

The jewelweed family (Balsaminaceæ), including the touch-me-not (Impatiens biflora and aurea) in moist places. The garden balsam (Imp. balsamea) also belongs here.

968. Order Rhamnales.—Shrubs, vines, or small trees. There are two families, the buckthorn (Rhamnaceæ), the grape family (Vitaceæ), including the grapes (Vitis), the American ivy (Parthenocissus quinquefolia = Ampelopsis quinquefolia), in woods and thickets, eastern North America, and much planted as a trailer over porches. The Japanese ivy (P. tricuspidata = A. veitchii) used as a trailer on the sides of buildings belongs here.

969. Order Malvales.—Herbs, shrubs, or trees.

The linden family (Tiliaceæ). Example, the basswood or American linden (Tilia americana.)

The mallow family (Malvaceæ), including the hollyhock, the mallows, rose of Sharon (Hibiscus), etc.

970. Order Parietales, with seven families in the eastern United States. The St. John’s wort (Hypericum) and the violets each represent a family. The violets (Violaceæ) are well-known flowers.

971. Order Opuntiales.—These include the cacti (Cactaceæ), chiefly growing in the dry or desert regions of America.

972. Order Thymeleales, with two families and few species.

973. Order Myrtales.—Land, marsh, or aquatic plants. The most conspicuous are in the evening primrose family (Onagraceæ), including the fireweeds, or willow herbs (Epilobium), and the evening primrose (Onagra biennis = Œnothera biennis).

974. Order Umbellales.—Herbs, shrubs, or trees, flowers in umbels.

The ginseng family (Araliaceæ). This includes the spikenards and sarsaparillas in the genus Aralia, and the ginseng (or “sang”), Panax quinquefolium.

The carrot family (Umbelliferæ). This family includes the wild carrot (Daucus carota), the poison-hemlock (Cicuta), the cultivated carrot and parsnip, and a large number of other genera and species.

The dogwood family (Cornaceæ). The flowering dogwood (Cornus florida), abundant in eastern North America, is an example.

Series 2. GAMOPETALÆ (= Sympetalæ or Metachlamydæ). Petals partly or wholly united, rarely separate or wanting.

975. Order Ericales.—There are six families in eastern United States. Examples:

The wintergreen family (Pyrolaceæ), including the shin-leaf (Pyrola elliptica).

The Indian-pipe family (Monotropaceæ), with the Indian-pipe (Monotropa uniflora) and other humus saprophytes. (See paragraphs 182-191.)

The heath family (Ericaceæ). Examples: Labrador tea (Ledum), in bogs and swamps in northern North America. The azaleas, with several species widely distributed, are beautiful flowering shrubs, and many varieties are cultivated. The rhododendrons are larger with larger flower clusters, also beautiful flowering shrubs. R. maximum in the Alleghany Mountains and vicinity, from Nova Scotia to Ohio and Georgia. R. catawbiense, usually at somewhat higher elevations, Virginia to Georgia. The mountain laurel (Kalmia latifolia) and other species rival the rhododendrons and azaleas in beauty. The trailing arbutus (Epigæa repens) in sandy or rocky woods is a well-known small trailing shrub in eastern North America. The sourwood (Oxydendrum arboreum) is a tree with white racemes of flowers in August, and scarlet leaves in autumn. The spring or creeping wintergreen (Gaultheria procumbens) is a small shrub with aromatic leaves, and bright red spicy berries.

The huckleberry family (Vaccinaceæ) includes the huckleberries (example, Gaylussacia resinosa, the black or high-bush huckleberry, eastern United States), the mountain cranberry (Vitis-Idæa vitisidæa = Vaccinium vitisidæa) in the northern hemisphere; the bilberries and blueberries (of genus Vaccinium); the cranberries (examples: the large American cranberry, Oxycoccus macrocarpus and the European cranberry, Oxycoccus oxycoccus, in cold bogs of northern North America, the latter also in Europe and Asia).

976. Order Primulales.—Two families here. The primrose family (Primulaceæ) contains the loosestrifes (Steironema), star-flower (Trientalis), etc.

977. Order Ebenales.—Of the four families, the ebony family (Ebenaceæ) contains the well-known persimmon (Diospyros virginiana) and the storax family (Styracaceæ) with the silverbell, or snowdrop tree (Mohrodendron carolinum).

978. Order Gentianales.—Herbs, shrubs, vines, or trees. Six families in the United States.

The olive family (Oleaceæ) includes the common lilac (Syringa), the ash trees (Fraxinus), the privet (Ligustrum).

The gentian family (Gentianaceæ) among other genera includes the gentians (Gentiana).

The milkweed family (Asclepiadaceæ) contains plants mostly with a milky juice. Asclepias with many species is one of the most prominent genera.

979. Order Polemoniales.—Mostly herbs, rarely shrubs and trees. Fifteen families in the eastern United States.

The morning glory family (Convolvulaceæ) includes the bindweeds (Convolvulus), the morning glory (Ipomæa), etc.

The dodder family (Cuscutaceæ) includes the dodders, or “love-vines.” There are nearly thirty species in the United States. The stems are slender and twine around other plants upon which they are parasitic (see paragraph 179).

The phlox family (Polemoniaceæ). The most prominent genus is Phlox. Over forty species occur in North America.

The borage family (Boraginaceæ) includes the heliotrope (Heliotropium), the hound’s-tongue (Cynoglossum), the forget-me-not (Myosotis), and others.

The vervain family (verbenaceæ) contains the verbenas.

The mint family (Labiatæ) contains the mints (Mentha), skull-cap (Scutellaria), dead-nettles (Lamium).

The potato family (Solanaceæ) includes the ground-cherry (Physalis), the nightshades (Solanum), the tomato (Lycopersicon), tobacco (Nicotiana).

The figwort family (Scrophulariaceæ) includes the common mullein (Verbascum), the monkey-flower (Mimulus), the toad-flax (Linaria), turtle’s-head (Chelone), and many other genera and species.

The bladderwort family (Lentibulariaceæ) includes the curious bog or aquatic plants with finely dissected leaves, and with bladders in which insects are caught (Utricularia).

The trumpet-creeper family (Bignoniaceæ) includes the trumpet-creeper (Bignonia), the catalpa tree, and others.

980. Order Plantaginales with one family (Plantaginaceæ) includes the plantains (Plantago).

981. Order Rubiales with three families is represented by the madder family (Rubiaceæ) with the bluets (Houstonia), the button-bush (Cephalanthus), the partridge-berry (Mitchella), the bedstraws (Galium), etc.

The honeysuckle family (Caprifoliaceæ) with the elder (Sambucus), the arrowwoods and cranberry trees (Viburnum), the honeysuckles (Lonicera), etc.

982. Order Valerianales with two families includes the teasel family (Dipsacaceæ). Example, Fuller’s teasel (Dipsacus).

983. Order Campanulales with five families, the corolla usually gamopetalous.

The gourd family (Cucurbitaceæ) includes the pumpkin, squash, melon, and a few feral species. Example, the star-cucumber (Sicyos angulatus), in moist places in eastern and middle United States.

The bell-flower family (Campanulaceæ) includes the hare-bells or bell-flowers (Campanula), the lobelias (example, Lobelia cardinalis, the cardinal-flower), etc.

The chicory family (Cichoriaceæ) includes the chicory or succory (Cichorium intybus, known also as blue-sailors), the oyster-plant or salsify (Tragopogon porrifolius), the dandelion (Taraxacum taraxacum = T. densleonis), the lettuce (Lactuca), the hawkweed (Hieraceum), and others.

The ragweed family (Ambrosiaceæ) includes the ragweeds (Ambrosia), the cockle-bur (Xanthium), and others.

The thistle family (Compositæ) includes the thistle (Carduus), asters (Aster), goldenrods (Solidago), sunflowers (Helianthus), eupatoriums or joepye-weeds, thoroughworts (Eupatorium), cone-flowers or black-eyed Susans (Rudbeckia), tickseed (Coreopsis), bur-marigold or beggar-ticks or devil’s-bootjack (Bidens), chrysanthemums, etc.