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 11 green stems DHJanzen100320.jpg high resolution
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| Just as a number of species of deciduous trees in the far north and subarctic have green stems/trunks and photosynthesize in winter, a number of species of desert plants (here, a palo verde tree, Parkinsonia, Fabaceae, introduced from New World deserts to North African deserts) have green stems that are photosynthetic during the long rain-free periods. While cacti are among the most dramatic examples, many legumes (Fabaceae) do as well. With this Parkinsonia, the green stem concept is carried to the extreme involving even the smallest twigs and even the leaf petioles are very thick with tiny and widely spaced leaflets. | ||
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