. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. 58 Science of Plant Life do not open until the leaf is above water. If the leaves are raised entirely above the sur- face of the water, as sometimes happens when the plants are crowded, both surfaces develop stomata. Desert plants and water storage. In the desert, where the air is very dry and the scanty rainfall is confined to one or two periods in the year, plants have very great difficulty in securing water. The pereimial plants have various ways of' con- serving water from one r
. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. 58 Science of Plant Life do not open until the leaf is above water. If the leaves are raised entirely above the sur- face of the water, as sometimes happens when the plants are crowded, both surfaces develop stomata. Desert plants and water storage. In the desert, where the air is very dry and the scanty rainfall is confined to one or two periods in the year, plants have very great difficulty in securing water. The pereimial plants have various ways of' con- serving water from one rainy period to the next. The barrel cac- tus has no leaves at all, and the stem is a thick cylinder composed largely of water-storage tissue; it may live without water for 2 years or longer. Some of the desert shrubs have leaves during the rainy periods only, and these are shed as soon as the drought comes. Still others, like the agaves, have very thick, leathery leaves with much internal water-storage tissue and a very low transpiration Fig. 38. Desert plants, including forms of Cereus, prickly pear (Opuntia), Yucca, Euphorbia, and cen- tury plant {Agave).. 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
