EPIPHYTES

The Greek word epiphyte refers to the fact that these are plants that grow on other plants (epi = on, phyte = plant). The host plant is typically a tree, so epiphytes usually have no contact with the ground. But they are not parasitic. They get nutrients from decaying organic matter on the surface of the host plant, and directly from rain. This is why epiphytes are also seen growing on utility poles, electrical lines, or other non-living heights.

Since they are not in contact with the ground, epiphytes cannot pick up soil moisture through their roots. Instead, they rely on moisture absorbed from the air, or captured in “cups” formed by the leaves. Given that humid environments are best for epiphytes, the valley is generally not prime habitat. Epiphytes are most abundant in the cloud forests at higher altitudes. In fact, it is estimated that 20% of all plant species in Podocarpus Park are epiphytes. Nonetheless, some species of epiphytes can be seen almost anywhere in the low to mid elevations in the valley.

Bromeliads
Bromeliads are in the same family as pineapples. Not all bromeliads are epiphytes. Some species can grow as both epiphytes and terrestrial plants. Bromeliad species range enormously in size. Some are tiny, hair-like tufts, such as the Tillandsia species shown on the right, a common site on telephone lines. Others, such as the Guzmania species pictured on the left, can be very large. The rosette formed by the basal leaves of a large bromeliad can hold several litres of rain. These rosettes are an important reservoir for dry periods, and create habitat for insects and frogs. Photosynthesis is usually lower in the dry season, to conserve moisture. This is why the leaf-tips of some bromeliads turn red in the dry season. With a reduced concentration of the green chlorophyll pigment, the red pigment that is found at the top-end of the leaf shows through.

Orchids
Many orchids are also epiphytes. There are thousands of species of orchids, most of which are hard to tell apart unless in flower. The Cattleya maxima orchid shown here is an epiphyte that originated on the Ecuadorian coast, but also grows in the valley. Because of the time of year that it blooms, it is known as the Christmas orchid. Its large and beautiful mauve-coloured flowers are unmistakable. The flowers of many orchid species are actually inconspicuous and dull, but are beautifully adapted for pollination. The many species at Vilcabamba’s orchid garden (located next to the zoo in Yamburara, a fifteen minute walk east of town) give a sense of the diversity of these incredible plants.

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