. Class-book of botany : being outlines of the structure, physiology and classification of plants : with a flora of the United States and Canada. Botany; Botany; Botany. J2 THK PHiENOQAMIA HOW DEVELOPED. CHAPTER III THE PH^NOGAMIA HOW DEVELOPED. 103. The embryo. The plant in its earliest stage of life is an em* bryo, contained in a seed. It then consists essentially of two parts, the radicle and the plumule. We may discern both in many seeds, as the pea, bean, acorn. 104. Growth of the embryo. After the seed begins to grow or germinate, the embryo extends itself in two directions, to form the
. Class-book of botany : being outlines of the structure, physiology and classification of plants : with a flora of the United States and Canada. Botany; Botany; Botany. J2 THK PHiENOQAMIA HOW DEVELOPED. CHAPTER III THE PH^NOGAMIA HOW DEVELOPED. 103. The embryo. The plant in its earliest stage of life is an em* bryo, contained in a seed. It then consists essentially of two parts, the radicle and the plumule. We may discern both in many seeds, as the pea, bean, acorn. 104. Growth of the embryo. After the seed begins to grow or germinate, the embryo extends itself in two directions, to form the axis of the plant. The radicle or root-end grows downward, penetrating the dark damp earth as if to avoid the light, and forms the root or descending axis. The plumule, taking the opposite direction, ascends, seeking the light, and expanding itself as much as possible to the influence of the atmosphere. This constitutes the stem or ascending axis, bearing the leaves. 105. Growth of the terminal bud. first the ascending axis is merely a bud, that is, a growing point, clothed and protected by little scales, the rudiment- ary leaves. As the growing point ad- vances, and its lower scales gradually expand into leaves, new scales suc- cessively appear above. Thus the axis is always terminated by a bud. 106. Axillary buds. By the growth of the terminal bud the axis is simply lengthened in one direction, an undivided stem. But besides this, buds also exist, ready formed, in the axils of the leaves, one in each. 107. How branches are formed. These axil- lary buds, a part or all of them, may grow and develop like the ter^ minal bud, or they may always sleep, as in the simple-stemmed mullein or palm. But in growing they become branches, and these branches. Acorn (seed of Quercus j>alv»- tris)scrminating; 0, section show- ing the radicle (r) which is to be- come the root, and the two cotyledons (c) which arc to nourish it; 7, tho radicle r, descending; S and 9, the radicle, r, descendi
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectbotany, bookyear1861
