Cone and Seed Structures

is a pistil; -- and the seeds--usually two are borne at the base on the upper side of the cell or leaf. This is perhaps the simplest of all the pistils ; that is, it is in some particulars most like an ordinary leaf. CONE AND SEEDS, 117. Usually, however, the simple pistil consists of the blade of a leaf curved until the. edges meet and unite, forming a closed case, which is the ovary.. 118. That the closed pistil is a leaf rolled up, is shown by the fact that the pistil of the Double-flowering Cherry is sometimes found changed back again into a small green leaf, partly folded, as seen in the Figure, 80 SEWALL S BOTANY. 119. The line or seam down the inner side, which answers to the united edges of the leaf, and bears the seeds or ovules, is called the Inner or Ventral Suture. 120. The line or seam down the back of the ovary, and which answers to the midrib of the leaf, is called the Outer or Dorsal Suture. These sutures may be seen in the common Pea pod. 121. The seeds are always borne on the ventral suture, that is, on the edges of the leaf or leaves that make up the pistil. COMPOUND PISTIU THE FKUIT. 81 A 122. simple pistil can have but one cavity or cell while a compound pistil (one made up of more than one leaf) may have but one cell, or it may have as many as there are leaves. Three leaves may unite to form one cell, or they may so unite as to form three cells, as seen in the Figures LESSON XII. THE FEUIT. 123. The ripened ovary with its contents, is the Fruit. When it adheres to the ovary, the calyx also becomes a part of the fruit. In the apple and pear the calyx forms the entire part of the fruit that we eat ; the Core is the ripened ovary containing the seeds. 82 sewall's botany. 124. Some fruits, commonly so called, are not fruits at A all, according to the definition just given. strawberry, for example, is only an enlarged and pulpy stem (receptacle), bearing on its surface the real fruits, the ripened ovaries, commonly called seeds. STRAWBERRY. 125. When, as the ovary ripens, its wall thickens and becomes soft, we have what is called a Fleshy Fruit. The Gooseberry, Blueberry, Cranberry and Currant, the Tomato and the Grape, are examples of fleshy fruits. The Pumpkin, Squash, Cucumber and Melon are examples of another sort of fleshy fruits. The Apple, Pear and Quince are also examples of fleshy fruits ; but here the fleshy part is made up of the thickened walls of the calyx tube, and not of the softened wall of the ovary. 126. When a fruit is partly hard and partly soft or fleshy, it is called a Stone-Fruit. The Cherry, the Plum and Peach are familiar examples. We 127. have seen that the pistil is formed from a leaf. Now, the stone of a stone-fruit is formed from the upper part THE FRUIT. 83 of this leaf (the inner part, when rolled), while the lower part of the leaf forms the outer, soft or fleshy portion. 128. It is a curious fact that leaves are much denser on the upper than on the under side. 129. When the walls of the ovary remain herbaceous in texture, or become thin, we have the Dry Fruit The real or botanical fruit of the Strawberry, and the fruit of the Buttercup, are examples of dry fruits. RASPBERRY. 130. In the Raspberry and Blackberry, each grain or globular portion is a pistil that has ripened into a miniature stone-fruit, so that in the Strawberry we eat the stem or 84 sewall's botany. receptacle ; in the Raspberry we eat a cluster of stone- fruits, like cherries on a very small scale ; and in the Black- berry we eat both a cluster of stone-fruits and the stem or receptacle on which they grow. BLACKBERRY, 131. When the wall of the ovary is thin and adheres to the seed, so that the wall and the seed seem to be incorporated into one body, the fruit is called a Caryopsis or Grain. Wheat and Indian Corn arq familiar examples. THE FItUIT. 85 LEGUME. 86 sewall's botany. 132. When the seed is enclosed in a hard or bony wall, the fruit is called a Nut- The Acorn is, botanically speaking, a nut. ACORN. 133. The fruit of the Maple, the Elm, the Ash, is called Samara or Key-Fruit. A 134. simple- pod with its contents, such as constitutes the fruit of the Pea or Bean, is called a Legume, In the pod we readily &ee the structure of tlie pistil. The edges of the rolled leaf unite, and form the part to which the seeds are attached, and the seam opposite is the midrib of the leaf. 135. When a pod opens only along the inner suture, it is called a Follicle. FOLLICLE. 136. The peculiar pod of the Mustard family is called a Silique. THE SEED. 87 137. The fruit of the Pines, Spruces and the like, is called a Strobile or Cone. These cones consist of a collection of open pistils on a long receptacle, each bearing one or two naked seeds on its edges, near the base. LESSON XIII. THE SEED. 138. The seed consists of two things, a miniature plant called th6 Embryo, and a quantity of starch which surrounds this embryo and furnishes it food. 139. Soak a bean in warm water a few hours, or put it in warm, moist earth for a day or two, and then examine it. You will plainly see the little plant nicely packed in its store-house of food. SEWALL S BOTANY. GERMINATING BEAN. 140. This starch is slowly converted into sugar, and^ when it is thus changed, is. dissolved, and the little plant feeds upon and consumes it. Then the plant is able to obtain its food from the earth and air. LESSON XIV. HOW PLANTS GROW. A 141. plant grows from the seed, becomes an herb, a shrub or a tree, matures seeds, and these seeds in turn pro- duce other plants. HOW PLANTS GKOW. 89 GERMINATING PLANT. 142. The increase of a living thing in size and substance is called Growth. 143. If we examine a leaf, or any part of a plant, with a microscope of high power, we find that it is made up of Cells. These cells are from one-thirtieth to one-thousandth of an inch in diameter, commonly from -^ to tio" of an inch. Thus there are commonly, from twenty-seven million to one hundred and twenty-five million cells in a cubic inch. 90 SEWALL'S BOTANY.. 144. The botanist observes three steps in all vegetable growth First, the growth of each cell until it attains its full size; Second, the multiplication of the cells' in number; and, Third, the arrangement of these cells in some regular order, thus producing^ definite forms. 145. This collection of cells constitutes what the botanist calls Cellular Tissue ; and when the walls of the cells become thick and hard, they form the* Wood. This woody material is ari;anged in two different ways, making two kinds of woody stems. 146. One kind we see in the Coru-stalk ; the other in the Oak and Maple---in fact, in all our common trees. The former is called the Endogen,or ^^ Inside Grower;" the latter the Exogen or " Outside Grower." EXOGENOUS STJEM, HOW PLANTS GBOW. 91 ENDOGENOUS STEM. 147. In the Endogen we find the oldest and hardest fibers of the wood next to the surface^ and the newest, softest fibers at or near the center, 148. In the Exogen we find a layer of new, soft wood on the outside or surface of tlie stem, and the hardest, oldest wood inside, toward the center. A 149. layer or circle of wood is added each year ; so that by counting these circles we can determine the age of the' tree. 150. Each of these kinds of stems has these characteristics : 1st, the Endogen grows from the inside j 2d, it bears 92 sewall's botany. parallel-veined leaves; 3d, its seeds produce but one seed leaf. 151. 1st, the Exogen grows by additions to the outside 2d, it beairs net-veined leaves ; 3d, its seeds produce two seed leaves. 152. In the exogen the livmff parts of the plant are, the rootlets at one extremity, the, bud and leaves at the other ; and these are connected by two contiguous zones of the newest or latest growth, one of wood and one of bark. These parts of the tree are renewed every year. LESSON XV. THE CHEMICAL COMPOSITION OF PLAKTS. 153. If we completely burn a leaf or bit of wood, almost all of it disappears into and becomes a part of the air. Nothing but the ash (ashes) remains. This ash is the part of the plant that came from the earth. The part that disappeared in the air, amounting to from eighty-eight to ninetynine per cent., is the part that came from the air. 154. The plant, then, feeds upon the earth and air. It converts the lifeless, inorganic elements into living or organic things. 155. In the foregoing lessons we have had under consid- eration only the higher classes of plants. There are others, of lower grades, called Cryptogamous or Flowerless Plants ; such are the Ferns, Mosses, Sea-weeds, Mushrooms, etc. These are more difficult to study, but to the advanced student in Botany are intensely interesting. suggestions, Model Lessons AND EXAMPLES. SUGGESTIONS. MODEL LESSONS AND EXAMPLES. This little work is intended for a text-hook. The teacher, with the aid of specimens of plants or parts of plants, can -- elaborate the text preach the sermon. The book does not treat of details of any one of the subjects, but aims to fix in the mind of the pupil the general outline, the main points of each topic. It is better to study plants to get a knowledge of Botany^ than to study Botany (the book) to get a knowledge of plants. Everything that the book teaches about plants (except the names) may be learned by studying the plants themselves. The book may also assist the pupil, by directing him how and where to find things. It will also lead him to follow some systematic order, so that what he learns shall not be to him a mass of disconnected, unrelated facts, but an harmonious whole. Let the pupil bring leaves, such as he can find, and study their forms. Let him examine them as to their general outline^ hase^ margin, apex, and compare them with the cuts or figures in the book. m He will soon learn that several of the names used describing leaves, may apply to one and the same leaf j as, 96 sewall's botany. for instance, a leaf may be lanceolate as to its general outline, while the base may be more or less cordate or sagittate, its apex acute or.acuminate, its margin dentate or serrate, etc. Again, he will find kaves that do not correspond exactly to any one of the forms mentioned, and to describe which would require such terms as linear-oblong, oblong-lanceolate, lance-linear, roundish-ovate, broadly linear, oblong-ovate. These and many other such compound names are used by the botanist in describing leaves. The pupil might find it difficult, for instance, to tell whether the leaf of the common Lilac is cordate or ovate ; the botanist describes it as cordateovate. Let the pupil bring leaves, stems of various forms, flowers, fruit, in fact anything that will assist him to understand the subject in hand. In the closing pages of this Appendix I have given examples of the different leaf-forms, and of the several parts of the plant spoken of in the text. They are given as examples simply, only a few of the many. The teacher inay find others that are better. I have endeavored to give 3uch as are familiar, and the examples of leaf-forms are typical, that is, each is quite exactly of the form indicated by the name. For instance, there are many leaves that are -- somewhat lanceolate or cordate or ovate not exactly lanceolate or cordate Or ovate, but approaching