OCOTILLO (Fouquieria splendens)
Part of a stem of ocotillo, showing a young, fresh flush of leaves following rains. These leaves can appear within 3 days of a brief spell of rain, and are shed quickly when the soil moisture level begins to fall. Even in the absence of leaves, the stem may continue to photosynthesise beneath its grey-coloured, waxy coating. When new stems of ocotillo are produced they elongate and produce "primary leaves" with stout leaf stalks (petioles). These petioles remain when the leaf blades are shed and they become thickened and woody, giving rise to the conspicuous spines. Then very short branches emerge from the axils of these spines (modified leaf stalks) and these short branches produce clusters of leaves like those seen in the image above. This production of new leaves happens repeatedly over several years, but the branches never elongate to become visible as true branches. |
