. Essentials of botany. Botany; Botany. 98 ESSENTIALS OF BOTANY careful sketch of its under surface, about natural size. Label the broad expanded part the blade, and the stalk by which it is attached to the twig, leaf-stalk or petiole. Study the outline of the leaf and answer these questions: (a) What is the shape of the leaf taken as a whole ? (See Appen- dix.) Is the leaf bilaterally symmetrical, , is there a middle line running through it lengthwise, along which it could be so folded that the two sides would precisely coincide ? (h) What is the shape of the tip of the leaf? (See Appendi
. Essentials of botany. Botany; Botany. 98 ESSENTIALS OF BOTANY careful sketch of its under surface, about natural size. Label the broad expanded part the blade, and the stalk by which it is attached to the twig, leaf-stalk or petiole. Study the outline of the leaf and answer these questions: (a) What is the shape of the leaf taken as a whole ? (See Appen- dix.) Is the leaf bilaterally symmetrical, , is there a middle line running through it lengthwise, along which it could be so folded that the two sides would precisely coincide ? (h) What is the shape of the tip of the leaf? (See Appendix I.) (c) Shape of the base of the leaf? (See Appendix I.) (d) Outline of the margin of the leaf? (See Appendix I.) Notice that the leaf is traversed length- wise by a strong midrib and that many so- called veins run from this to the margin. Are these veins parallel ? Hold the leaf up towards the light and see how the main veins are con- nected by smaller veinlels. Examine with your glass the leaf as held to the light and make a careful sketch of portions of one or two veins and the intersecting veinlets. How is the course of the veins shown on the upper surface of the leaf? Examine both surfaces of the leaf with the glass and look for hairs distributed on the surfaces. Describe the manner in which the hairs are Fig. 59. Netted Vein- ing (pinnate) in Leaf of Foxglove. The various forms of leaves are classed and described by botanists with great minuteness, ^ not simply for the study of leaves themselves, but also because in classify- ing and describing plants the characteristic forms of the leaves of many kinds of plants form a very simple and ready means of distinguishing them from each other and 1 See Kerner and Oliver's Natural History of Pla7Us, Vol. I, pp. 623-637. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1908
