When leaves are neither folded nor rolled in the bud, they are said to be FLAT. ARRANGEMENT OF LEAVES IN THE BUD. By the arrangement of the leaves in a bud is meant the ways in which they are placed in relation to each other. For instance, Fig. 285 shows what is called the equitant arrangement. FIG. 285. EQUITANT.-When opposite conduplicate leaves overlap each other at the base, as seen in Fig. 285, the arrangement is called equitant. Leaves are always arranged in one or other of the two ways called valvate and imbricate. The VAL'VATE arrangement is seen when the edges of corresponding leaves barely touch each other. The IM'BRICATE arrangement is seen when the edges of the leaves overlap each other. Fig. 285 shows an imbricate arrangement. The directions for observing the folding and rolling of leaves apply also to the study of their arrangement. But there are several different ways in which imbricate leaves are placed, and it is sometimes quite difficult to make them out. The best way to study the arrangement of leaves in the bud is to cut off the top of the bud with a sharp knife, and look down on the cut edges, which will show not only whether the leaves are imbricate or valvate, but also, if they are imbricate, the particular mode of overlapping. In most cases, however, a magnifying-glass is needed to show the details of a complex arrangement, and so we shall leave the illustration of this branch of vernation to be taken up again in the Second Book of Botany. In your notes about trees you can now include your discoveries about the buds of the particular kinds of woody plants you are studying. Answer the following questions in regard to each sort by frequent observations made during their growth. Answer them in writing in your book for each of the woody plants that you have selected to study throughout the year. QUESTIONS ON THE BUDS OF A PLANT. When do the buds begin to swell? Are they naked, scaly, woolly, or gummy? How long is it from the first bursting of the bud till the leaves are full grown? What changes of color do the leaves undergo during growth? Are the first-formed leaves as large as those formed later in the season? What becomes of the bud-scales as the buds unfold? CHAPTER IX. STEM AND ROOT. EXERCISE LXV. What are Roots? CAREFULLY pull up a buttercup, or any common plant, and rinse away the dirt from the roots. Take the stem-schedule on page 63, and answer its questions as if they were asked concerning these roots. Look at the tip of the stem, or of one of the branches of the stem, and compare it with the tip of a rootlet. What is the difference between them? What appendages has the stem that you do not find on the root? How do the root and stem differ in color? Where do branches start from on the stem? |