. La botanique pour les lycées et collèges. La botanique. De LEA OUI DANS OENEEAL. 147. Fig. 125.-Trois-feuilles lobées de Hepatica. 194.-feuilles, comme les autres membres de l'usine-corps, peut direction au cours de leur croissance. Au début, ils sont toujours simples, et si la croissance est uniforme le résultat est une simple feuille ; si, cependant, comme il arrive fréquemment, la croissance est plus rapide sur certains points, les branches peuvent survenir, comme dans le soi-disant com- pound feuilles. Tous les grada- tions sont observables entre les feuilles simples, où la croissance a été absolument uniformes (production de marge entière), à feuilles composées avec notice de transmission

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. Botany for high schools and colleges. Botany. OF LEA YES IN OENEEAL. 147. Fig. 125.—Three-lobed leaf of Hepatica. 194.—Leaves, like other members of the plant-body, may branch during their growth. At first they are always simple, and if the growth is uniform the result is a simple leaf ; if, however, as frequently happens, the growth is more rapid at certain points, branches may arise, as in the so-called com- pound leaves. All grada- tions are observable between simple leaves, in which the growth has been absolutely uniform (producing entire margins), to compound leaves with jointed leaflets. The differentiation is here much like that which takes place in passing from the thallome to the form of plant-body with distinct caulome and phyllome. The simplest cases are those in which the branches are rudimentary, as in the serrate (Fig. IM, A), dentate (Fig. 134, B), crenate (Fig. 134, G), and other similar forms. When the branches are more pi'ominent they give rise to lobes of various kinds (Figs. 135, 136). Where the longitu- dinal growth of the leaf (not of its branches) is but little, the lobes ap- pear to radiate from a common point, as in hepatica, mallow, maple, etc.; such are called radiately, pal- inately, or digitately lobed. Where, as in the oak, the longitudinal growth of the leaf is considerable, the lobes are laterally arranged upon a central portion ; such leaves are said to he pinnately lobed. 195.—Leaf-branches frequently become so developed that thoy themselves form distinct leaves, and thus we have what is termed the compound leaf (Figs. 137 and 138). Terms similar to those used in the case of lobed leaves are here used also; thus where the secondary leaves (leaflets) grow from an extremely short axis, so that they radiate from a. 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 the original wo

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