Net-Veined vs Parallel-veined Leaves

tear regularly -- Note. The pupil should make a collection of leaves, and separate the parallel-veined from the net-veined leaves. 20 SEWALL'S BOTANY. that is, not in any particular direction. Hold it up to the light, and you will see that the ridges or ribs run in almost every direction, and form a sort of net-work. Such leaves are called Net-veined. 14. In net-veined leaves, you will frequently find that a single strong rib, called the midrib, which seems to be a continuation of tlie leaf-stalk, runs directly through the middle of the leaf to the very top, and that from this midrib the lateral or side veins all diverge. Such leaves are called Feather-veined. 15. In other net-veined leaves, the leaf-stalk seems to divide, at the point where it joins the leaf, into three or more portions or ribs, of nearly equal size ; and these give off veins and veinlets. Such leaves are called Radiate, or Palmate-veined. LESSON III. THE FOEMS OF LEAVES. 16. Leaves have an almost infinite variety of forms. Such names are given them as their forms suggest. 17. Here is a group, each of which is named as to its general form : Linear, Lanceolate, Oblong, Elliptical, Ovate, Oblanceolate, Spatulate, Obovate. You will observe that the four last named taper toward the base. THE FORMS OP LEAVES 21 RADIATE-VEINED LEAF. sewall's botany. OVATE. OBLANCEOLATE. OfeLONG. LANCEOLATE. CUNEATE. ELLIPTICAL, THE FOBMB OF LEAVES. 23 SPATULATE. OBOVATE. LINEAR 18. Here is a group, each named from the shape of the base Auriculate, Hastate, Cordate, Reniform, Peltate. CORDATE. 24 SEWALKS BOTANY. ARTICULATE, SAGITTATE, THE rOKMS OF MiAVES. 25 HASTATE, 26 sewall's botany. 19. Here is a group, each named from the shape of the ^op or apea;: Acuminate, Acute, Obtuse, Truncate, Retuse, Obcordate. ACUMINATE. OBTUSE. TRUNCATE. RETUSE. THE FORMS OP LEAVES. 27 OBCORDATE. 20. Here is a group, each named with reference to the shape of the margin: Entire, Serrate, Dentate, Repand, Sinuate, Incised. REPAND. CRENATE. 28 SEWALL S BOTANY. 1 7 SERRATE. ENTIRE THE FOllMS OF LEAVES. 29 DENTATE. 30 sewaWs HOTANY. ' THE BOBMS OP LEAVES. 31 INCISED, 32 sewall's botany. 21. When the incisions in a leaf extend about half way to the middle, and are somewhat rounded, it is said to be Lobed. When the incisions extend more than half way, it is said to be Cleft. LOBED. When the incisions extend almost to the midrib or to the base of the leaf, it is said to be Parted. When the incisions extend quite to the midrib or to the base of the leaf, it is said to be Divided. THE FORMS OF LEAVES. 3B PARTED. 34 sewall's botany. 22. There are two kinds of net-veined leaves, you will remember; arid each kind may be loled^ cleft^ parted^ or divided^ as you will see in the Figures. FiCATHER-VElNED LOBED. THE FORMS OF LEAVES. 35 FEATHfiR-VEINED CLEFT. 36 sewall's botany. FEATHER-VEINED PARTED. THE FORMS OF LEAVES. 87 FEATHER-VEINED DIVIDED. 38 SEWALL\S BOTANY. FEATHER-VEINED COMPOUND LEAF. THE FOBMS OF LEAVES. 39 A 23. Compound Leaf is one which has its blade in two or more entirely separate parts, called Leaflets. Compound leaves are of two kinds, Feather-veined and Radiate-veined. Feather-veined leaves may be Lobed, Cleft, Parted or Divided. Radiate-veined leaves may be Lobed, Cleft, Parted or Divided. RADIATE-VEINED COMPOUND LEAF. 24. In some plants the stem appears to run through the blade of the leaf, near one end. Such leaves are called Perfoliate. 40 SEWALL'S BOTANY. PERFOLIATE LEAVES. THE FORMS OF LEAVES. 41 EQUITANT LEAVES. 42 sewall's botany. 25. The stem does not really run through the leaf, but the leaf clasps the stem, and the heart-shaped lobes of the base grow together and enclose the st^m. 26. Such leaves as the Iris are called Equitant. They are each folded lengthwise in the middle, and are packed one over the other. LESSON IV. ARRANGEMENT OF LEAVES. 27. Leaves are arranged on the stem in some regular order. Different kinds or species of plants have different kinds of leaf-order, but the same kind or species always has the same leaf-arrangement, 28. When a stem bears two leaves on the same node, one is separated from the other by just one-half of the circumference of the stem, and the leaves are said to be Opposite or Two-ranked. The Indian Corn is a good illustration. TWO-RANK�D� AKKANGKMENT OF LEAVES. 43 29. When only one leaf is found arising from a node, the leaves are said to be Alternate. 30. The simplest arrangement of alternate leaves is called the Three-ranked that is, the leaves are separated by one- ; third of the circumference of the stem, and three leaves complete one cycle. 31. Beginning with any leaf on the stem, as (1) in the figure, the next above it (2) is found to be one-third of the circumference of the stem from (1) ; the next (3) is onethird of 'the circumference from (2), and two-thirds of the circumference from (1), the leaf at which we began to count ; the next (4) is one-third of the circumference from (3), and three-thirds, or the whole circumference, from the leaf we began with. We 32. find that three leaves form a complete cycle, and that the fourth leaf stands directly over, or in a vertical line with, the first. The Alder and the Sedges are illustrations of the three-ranked cycle. 33. The I arrangement is, perhaps, the most common. The Cherry, the Apple, the Peach afford illustrations of it. Here the leaves are two-fifths of a circumference from each other. 34. The next is the f arrangement. Here the leaves are three-eighths of a circumference from each other. The Osage Orange is an illustration. 35. If we write in ordjer the series of fractions which represent the simplest 'forms of leaf-arrangement that we have observed, viz., |, i, |, |, we observe that the numerator 44 SEWALL'S BOTANY. FIVE RANKED. THREE RANKED, THE STEM. 46 of the third fraction is the sum of the numerators of the first and second, and the denominator of the third is the sum of the denominators of the first and second. The numerator of the fourth is the sum of the numerators of the second and third, and its denominator the sum of their denominators. By applying this simple rule we nmy extend this series; i thus, i, I, I, y�-5, ^, il, &c. 36. Each fraction in the above series tells us two things:. First. How far distant, or what part of a circumference of the stem, one leaf is from another. 37. Second. The numerator tells us how many times we must pass around the stem to find a leaf directly over, or in a vertical line with, the first one taken ; and the denominator tells us the number of leaves in the circle or circles passed. Thus, I, |, f, I, J^^ showing two cycles and five leaves; h h h �> �> �� �) �� three cycles and eight leaves. 38. In the first of the above examples, we should pass around the stem twice, and find five leaves in the two cycles. In the second, we shpuld pass around the stem three times, and find eight leaves in the three cycles. LESSON V. THE STEM. 39. The growing points of the stem are called Buds. A bud is a collection of leaves on a short stem or axis. By expanding its leaves and lengthening the axis, a bud develops into a Branch, 46 sewall's botany. 40. When a bud grows upon the end of a stem, it is called TerminaL TERMINAL BUD. AXILLARY BUDS, AXILLARY BUD. STEM, WITH BUDS. THE STEM. 47 ROOT -STOCK. 48 sewall's botany. When it grows in the axil of the leaf, that is, in the point where the upper surface of the leaf joins the stem, it is called Axillary. 41. When buds spring from any other part of the stem, they are called Adventitious. 42. When a tree or shrub is wounded or bruised, there will frequently appear a tuft or cluster of irregular shoots or branches ; these come from adventitious buds. 43. The jointed stem of grasses ^nd similar plants is called a Culm. 44. When the stem creeps along the ground or beneath its surface, it is called a Root-stock. It develops a bud at its end every year, which grows, while the older portion of the root- stock decays. The Mint and the Quick-grass arQ good examples. 45. When a ^tem or branch grows under ground and becomes excessively thickened by a deposition of starc;hy matter^ and is furnished with small scales having coiicealed buds (eyes) in their axils, it is called a Tuber. The common Potato is a good example of the tuber. 46. When an under-ground stem takes a solid, globular form,' with buds at the top, apid roots below, and is filled with starchy matter, it is called a Corm, The Crocus is an example. 47. When an under-ground stem is short, and bears many thickened leaves upon it, so that it seems to consist mainly of these, it is called a Bulb. THE STEM. 49 TUBER, 60 SEWALL S BOTAKY. If you compare the bulb of the Canada Lily with the strong buds of the Hickory, you will see that they are quite alike in structure. 48. ~ Sometimes we find small bulbs above ground, in the axils of the leaves. Such are called Bulblets. You will find them on the Tiger Lily. They look like, and are sometimes called, seeds, but are really little bulbs. THE STEM. 51 BULB. 62 SEWALL S BOTANY. SUCKER. 49. When a branch grows from an under-ground stem, it is called a Sucker. The Raspberry is an example. THE STEM* 58 50. When a branch trails, or runs along the surface of the ground, and takes root, and sends up a shoot, we call it a Stolon. 54 SEWall's botany. A 51. slender and leafless branch that takes root only at the tip, is called a Runner. 52. When a branch is slender and leafless, and tends to wind about something, to give support to the plant from which it grows, it is called a Tendril. THE STEM. 55 TENDRIT^ 56 sewall's botany. 53. When a branch is stunted, 'hardened, leafless and pointed, it is called a Thorn, We 54. Sometimes a thorn is a leaf. can easily deter- mine, however, by its place, whether the thorn i^ a branch or a leaf. If it is in the axil of the leaf it is a branch; if not, it is a leaf. Branches of neglected apple or. pear trees sometimes change into thorns. The thorns of the Honey-Locust are developed from adven- titious buds. LESSON VL HOOTS. 65. When a single root descends directly from the seed, it is calle.d Simple Primary. The Beet is an illustration. Roots that descend in a cluster from the seed are called Multiple Primary. The Onion is an illustration. 56. When roots grow from any part of the stem, they are called Secondary. The roots seen above ground on the corn- stalk are an illustration. 57. When a plant is borne on the trunk or branchy of a tree, but derives its nourishment from^ the air, it is called an Epiphyte or Air Plant. A 68. plant which draws its nourishment from the juices of another, into whose trunk or branch it sends its roots, is called a Parasite. The Dodder is an illustration. BOOTS. 57 SIMPLE PRIMARY ROOT. 58 sewall's botany. MULTIPLE PRIMARY ROOT. THE FLOWER. 69 LESSON VII. THE FLOWER. 59. The Flower is a modified branch, consisting of stem and leaves, and is concerned in the productio^ of seed. The flow'er stem is very short, and the leaves differ from the ordinary or foliage leaves in form and color. 60. Flowers are developed from terminal or from axillary buds. The same plant commonly produces both kinds of foliage buds, but it rarely bears flower buds in both situations ; these are usually all terminal, or all axillary. 61. When all the flowers rise from axillary buds, the flowering is said to be Indefinite ; because, while the axillary buds produce flowers, the terminal (foliage) bud grows on, and continues the stem indefinitely. 62. The stem of a flower is called the Peduncle. Wheii a