What is an Orchid?
The Orchid Family
The orchid family (aka Orchidaceae) is the largest flowering plant family on earth with about 30,000 species. It is also one of the oldest plant families – developing about 84 million years ago. Being so old, orchids have had plenty of time to develop into very specialized organisms. It is specifically the orchid flower, rather than the foliage, that has developed in this specialized way. While orchids look very exotic, they are in their essence very primitive plants. The vascular system in their leaves is not nearly as developed as more modern plants and that leads to foliage that is not always very impressive. Their pollen is also very primitive – a fine dust, as fine as the spores of ferns, that is concentrated in “packets” known as pollinia. Because this pollen only comes in packets that cannot float freely through the air, orchids are entirely dependent on a pollinator – and over their eons of development, they have modified their flowers to trick a wide variety of pollinators into transporting their pollen from one flower to another.
What Exactly is an Orchid?
Sepals, the remains of the flower bud, are not a distinguished part of the flower with most plants. But with orchids, the sepals have been modified to essentially become a part of the orchid’s flower. Oftentimes they mimic the look of the petals, but they always function along with the rest of the flower to trick a pollinator into taking the pollinia to another orchid flower. There are always three sepals in an orchid flower except certain slipper orchids (such as Paphiopedilums) that have an overgrown dorsal (top) sepal and fused lateral (side) sepals.
The sepals of an orchid are unique in that they mimic the petals. An orchid has three petals, the bottom petal forms the orchid’s lip.
All orchids have a petal that forms a lip. For the pollinator, the lip often serves as a landing pad of sorts. Most orchids turn in the development of the bud so that the lip is at the bottom of the flower but some have a lip at the top and are called “non-resupinate”.
Orchids are found on every continent on Earth except Antarctica. While most people associate orchids only with tropical places they are found in a wide variety of ecosystems. In fact, Oregon boasts of over 40 species of orchid (interestingly, Hawaii, a tropical island, only has 3 native orchid species).
Supporting peoples’ association between orchids and the tropics, the densest orchid populations are in tropical areas of South America and Southeast Asia where many thousands of species exist.
Many of these places are unprotected and unregulated making most orchids endangered or threatened species.
Asters vs. Orchids…
Orchids are debatably the largest flowering plant family on Earth (30,000+ species). The only other contender for that title would be the aster family, Asteraceae, which is a much later development in terms of evolutionary history (42 MYA). This family includes asters, dandelions and daisies. The asters primarily differ from orchids in that they can have abiotic pollination – that is, they can reproduce via wind or water rather than depending on living beings. This produces a flower that has no need to mimic a pollinator, and therefore looks rather “basic”. Instead of focusing on attracting pollinators, asters (and most modern plant families) put their evolutionary energy into foliage that can withstand different ecoclimes leaving their flowers looking like… well… flowers.