Anatomy of Orchid Plants

The anatomy of orchid plants is truly unique. Even though there are 20,000 natural species and probably 100,000 hybrids, they all have many of the same characteristics that give them their unique appearance.

Flowers have both male and female organs. The unusual thing about orchids is that the male and female parts are both housed in the part called the column. The sepals and petals that give the orchid its look are located around the column, which is about the width of a finger.

The stigmatic surface that contains the female organs is located inside the column. The pollinia is located under the anther cap, and is made up of the male parts.

Orchids have three sepals that resemble its petals. There is a larger dorsal sepal and two lateral ones.

Although there is a bit of variation from one species to the next, usually, the sepals are a bit smaller than the petals. Actually, the sepals are the remnants of flower buds, and not actual petals. On some species, they are almost the same size as petals.

Orchids will always have three petals, no more no less. Two of the three are flat and kind of oval shaped. The third is usually flatter and larger. It also has an added feature called the lip, or labellum, which is the Latin term. This part acts as a platform for certain pollinators that the plant needs to reproduce.

These creatures come in many forms, such as bees, butterflies, hummingbirds and regular birds. Occasionally, bats will even do the job. All of these animals feed on the nectar and carry it with them to other plants on their legs and wings. In this way, they inseminate the other plants.

The petals will sometimes become elongated, so much so that they become twisted like the Paphiopedilium parishii. Sizes of petals will vary as well. Some petals have been known to reach lengths of 35 inches (90 cm). Such is the case with the Paphiopedilium sanderianum. Others, such as the Oncidium, are very small. In some cases, a tube shape will form on the lip and retain nectar at the base. This tube shape is referred to as the spur or angracecum.

The stem system that feeds the orchid is designed in a way that is very unique, compared to most other plants. This is because their roots are usually somewhat exposed due to the fact that they do not grow in soil. Epiphytes cling to trees, lithophytes grow on rocks, saprophytes are found in leaf litter, and terrestrials live in sand. For this reason, they need to utilize some very unique survival skills. They will use bird droppings as fertilizer, and use the water that drips off of leaves and tree bark.

         

Introduction to Orchid Gardening