Adaptations of Orchids

Flower Adaptations

• Orchid flowers are individualized from species to species, adapted for survival in different growing conditions and in the presence of different pollinators. The flowers have a common structure composed of three petals, two of them extending laterally from the center of the flower and third modified into a structure called a lip. This lip forms a cuplike structure where nectar collects, attracting pollinating insects. An orchid's flower color and structure evolved to attract specific pollinators unique to its environment.

Leaf Adaptations

• Because orchids grow in variety of environments even within the tropical forest, the food-producing leaf structures of individual species vary greatly, depending on the specific habitat. Many orchids growing directly on the ground have green, chlorophyll-filled leaves and use sunlight to create their food. Some epiphytic orchids, those that grow on the trunks of trees, have no green leaves but have chlorophyll in their exposed roots clinging to the tree's bark. Other orchids have no leaves at all and depend on a symbiotic relationship with fungus living in their roots for food.

Root Adaptations

• Even in the rainforest's wet environment, gathering and using water is challenging. Orchids developed modifications allowing them to capture and store water. The roots of epiphytic species are exposed to the air and susceptible to drying out. Epiphytic orchids developed a tough tissue called velamen covering the root's surface, helping them retain water. Ground-dwelling orchids often have tubers in their root systems, allowing them to store water in these fleshy masses during dry periods.

Other Adaptations

• Orchids have other modifications differentiating them from other plants. In their flowers, the male and female sex organs fused into a single organ know as a column, rather than two discrete structures as in most plant. Orchid pollen is also unusual in that it clumps together in sticky masses instead of remaining loose and powdery.