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 30 leaf arrangement DHJanzen100341.jpg high resolution
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| The plants leaves are often carefully arranged to reduce interference within the plant crown. The shadier a site (the less the light resource), the more often and more dramatic this is the case. Also, being in a wind-free area allows more precise positioning of leaves. Here a Costa Rican tree seedling puts out its new leaves in a spiraling whorled pattern, maximally filling the space available. Additionally, by the time the production pattern comes around the stem to where the next leaf will be above one below it, the one below it is far enough below it that the one above casts almost no shadow on it. You can convince yourself of this phenomenon by holding one sheet of paper over another below a light bulb, and gradually increase the distance between the two sheets, and observe what happens to the amount of light hitting the lower sheet of paper. Once this sapling has attained the canopy and is in both the full sun and the wind, such exact leaf positioning is neither as necessary nor as possible. | ||
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