. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. is6 Science of Plant Life branches or leaves. They re- spond to contact with a sup- port by coiling tightly about it. After attaching themselves, they develop mechanical tissue which gives the plant a firmer' support. In some vines, like the Boston ivy, the tendrils have at their tips sensitive disks which become cemented to the support. This type of tendril is especially effective in taking hold of the bark of trees, rock cHffs, and walls (Fig. 87). In the tropics, climbing stems m
. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. is6 Science of Plant Life branches or leaves. They re- spond to contact with a sup- port by coiling tightly about it. After attaching themselves, they develop mechanical tissue which gives the plant a firmer' support. In some vines, like the Boston ivy, the tendrils have at their tips sensitive disks which become cemented to the support. This type of tendril is especially effective in taking hold of the bark of trees, rock cHffs, and walls (Fig. 87). In the tropics, climbing stems may attain a length of more than 1000 feet. Thus the water transpired by the terminal leaves has to be carried for about a fifth of a mile within the plant. This suggests the need of an efficient conductive system in a climbing plant, and explains why the bulk of its slender stem is made up of con- ductive tissue. Stems of hydrophytes. We have seen that submerged leaves have distinctive forms and characteristic internal structures. Under-water stems also differ from those of land plants. In floating plants like duckweed, water hya- cinth, and Salvinia, the stems are short. Their conductive systems are poorly developed, and they are practically without mechanical Fig. 88. Climbing stems on a tree trunk in a tropical 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 Transeau, Edgar Nelson, 1875-1960. Yonkers-on-Hudson, N. Y. , World Book Co.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1921
