. A text-book of botany for secondary schools. Botany. STEMS 63 leaf-bearing structure, it continues to bear leaves when under ground; but often these leaves are much modified, either reduced in size so as to be mere rudiments, or used for some other purpose. The fact that a subterranean structure bears leaves of some kind indicates that it is a stem and not a root. Since both the stem and its leaves must be considered in connection with the underground habit, the shoot (§21) will be considered rather than the stem alone. In general the subterranean shoot is con- spicuously a region of food st
. A text-book of botany for secondary schools. Botany. STEMS 63 leaf-bearing structure, it continues to bear leaves when under ground; but often these leaves are much modified, either reduced in size so as to be mere rudiments, or used for some other purpose. The fact that a subterranean structure bears leaves of some kind indicates that it is a stem and not a root. Since both the stem and its leaves must be considered in connection with the underground habit, the shoot (§21) will be considered rather than the stem alone. In general the subterranean shoot is con- spicuously a region of food storage. The three following types are the most common. (4) Rhizomes.—This is probably the most common form of subterranean stem. It is usually horizontal, more or less elongated, and much thickened for food storage, and is often called the rootstock (Fig. 61). It advances througli the soil year after year, often branching, sending out roots be- neath and leaf-bearing branches into the air. As it continues to grow at the apex, it gradually dies behind, thus isolating branches in the case of branching rhi- zomes. It a very efficient method for the ^^^' ^^'—Rootstock of ix fern Ccommon brake), bearing young leaves. spreading of plants and is extensively used by grasses in covering areas and forming turf. The persistent continuance of some weeds, especially certain grasses and sedges that infest lawns and meadows, is due to this habit (Fig. 62). It is. 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 Coulter, John Merle, 1851-1928. New York, D. Appleton
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1906
