Orchids from elsewhere

"RONA: Greenhouse" by Bill_Barber on Flickr

It’s funny to think, but all those potted plants one sees for sale in the plant sections of places like Home Depot or the grocery store are native to somewhere. Many of them have become so common as houseplants that it’s hard to envision them growing out in the wild, in some steamy rainforest or a dry, sandy desert. In the case of the orchids usually found in such stores, the vast majority come from tropical rainforests where they grow as epiphytic plants, on the limbs or trunks of towering trees. The Phalaenopsis orchids such as the ones shown above are the genus most often sold in chain stores, and are native to tropical Asia, as are the Paphiopedilum orchids such as the ladyslipper I own.

"Cyrtochilum divaricatum" aka Oncidium costatum by Quimbaya on Flickr

Cattleya orchids, on the other hand, come from Central and South America. Oncidiums, such as the one shown above, are found primarily in the Central Americas. Dendrobium orchids range throughout tropical Australasia, as do the Cymbidiums. And these are just a small sprinkling of the many genera of orchids, representing the groups most commonly found in chain and garden stores.

"Wild Orchids in the Lyon Orchid Garden" by Dick on Picasa

One thing nearly all of these groups have in common is that they’re air plants, growing above the ground with their roots exposed. They collect their moisture and nutrients from the air and rainwater that runs down the tree or whatever substrate they’re growing on. Because of this, they can only grow wild in humid environments such as the rainforests. It’s also why they need special potting medium to keep at home. Since most homes aren’t nearly as humid as the orchid’s tropical habitats, we have to simulate the same conditions. Orchid potting medium is usually quite coarse and absorptive; bark and coconut shell is a common mix. There’s room for air to get through between the large pieces, but the pieces of bark absorb and slowly release moisture to the orchid’s roots, effectively maintaining a “humid” environment in the air pockets. If you planted an orchid in typical potting soil, it would likely suffocate and die, because the roots would rot with the constant moisture and lack of air circulation. Most orchids appreciate a regular misting with water or a tray of water underneath them which helps to keep the leaves from drying out too much, as well.

Cattleya labiata by Cristóbal Alvarado Minic on Flickr

Orchids have a long and storied history as houseplants. They have been artificially cultivated for more than 2000 years. The Chinese would use fragrant species – some of them can have very strong perfumes – to scent their households, placed strategically in a room designed around them. They really caught on in the 18th and 19th century, however, when European explorers began collecting specimens from the regions they visited. It might be that orchids owe their existence as houseplants to a single serendipitous decision made by Sir William Cattley in the early 1800s. Cattley, a British horticulturalist, was unpacking some tropical plants sent to him from South America by a colleague. The collected individuals had been placed between some common plants who were simply intended to be used as packing material. Curiosity must have got the better of Cattley, who decided what the heck, let’s plant some up and see what they do. One of them bloomed for him, producing the beautiful pink flowers above. Presumably his neighbours, when they saw them, said “I want a piece of that action!” and so tropical orchids became introduced into European cultivation. Or something like that. Incidentally, the pink flowers, the first described from their genus, were named by Cattley’s friend and fellow botanist John Lindley in honour of his “discovery”.

"Orchid-222.jpg" by Andy.Schultz on Flickr

It was a while before orchid enthusiasts figured out how to propagate the plants, however. At first, cultivated orchids were all wild specimens collected from the tropics and shipped back overseas. As the interest in orchids grew, so did the number of plants collected from the wild. Needless to say, this sort of free-for-all had a very negative impact on the populations of many of the species, and eventually laws had to be put in place requiring export permits for the species (whether wild-grown or cultivated) in order to control the movement of orchids from their native countries. These days, nearly all tropical orchids require a CITES (Convention on International Trade in Endangered Species) permit to be shipped across borders, even for those species who have stable populations. From a personal perspective, this seems a little overkill; with all the orchids in cultivation these days, shouldn’t they be focused on making it easier for growers to share cultivated stock to maintain a strong gene pool, rather than harder? After all, the more propagation done using pre-existing cultivated plants, the less people are going to want, or need, to take plants out of the wild. On the other hand, especially for poorer people in the countries where these species grow, it would be a really easy way to make a buck to just go into the forest and collect a whole bunch of orchids, and sell them off to an overseas buyer.

"Orchis mascula", the most common species used to make orchid ice cream; by Inklaar on Flickr

The word “orchid” is derived from orchis, the Greek word for testicle; it references the root bulbs of a terrestrial genus that grows in Greece and the Mediterranean region, whose paired tubers resemble that part of the male anatomy, and were thought to be an excellent aphrodisiac. The genus has now been labeled Orchis, and includes species such as O. mascula, above. These days, they’re still used to make a type of chewy ice cream called salep that resembles salt taffy in consistency. They’re so common that no one bothers to cultivate them, they’re just collected from the wild.

"Cycnoches barthiorum" by douneika on Flickr

Orchid flowers generally last a long time, up to two or three months or more in some species. The reason for this is that many have evolved very complex strategies for achieving pollination, usually ones that require that their pollinator do backflips and jump through hoops to get their reward, and so they need to ensure that their pollinators have enough time to actually do those backflips. Most tropical orchids don’t actually produce nectar as a reward. Instead, they rely on a number of other strategies to attract pollinators. Some encourage the patronage of Euglossine bees (often also known as “orchid bees”). The lady bees just go crazy for perfume, and the males desperately try to collect up as much as they can to offer the female. The orchids provide the bees a source of this perfume. Quite often, specific species of orchid have very specific species of bees that they’re attracting. When the bee comes to collect the perfume, it brushes against the pollen sac of the flower. On the next flower it goes to visit, the pollen sac has been positioned in just such a way that it will come into contact with the female bits, and thus pollinate the flower.

"Phragmipedium Besseae_Kew_2680" by KitLKat on Flickr

The ladyslipper orchids are sneaky plants. Their flowers offer no reward to their pollinators, but instead dupe the poor insects into visiting. They may use an odour to attract individuals to the flowers. Once at close range, shiny bits may resemble honeydew or nectar that the insect can collect. The bug goes to land on what looks like it should be a perch, but turns out to be a slippery wart. The insect tumbles into the flower’s pouch, the only way out of which is, because of the curved lip, up the back wall and through a tunnel that takes it past the plant’s anthers (the male parts), where a pollen sac is deposited on it. In order for the flower to get pollinated, the insect must then fall for the same trick a second time, climb back up through the second tunnel, and brush the appropriately-placed pollen sac against the second flower’s stigma (the female part).

"hand pollinating a vanilla orchid" by glowingz on Flickr

In cultivation, because of the specific requirements of the flowers for pollination, the job usually has to be done by humans. In the case of the vanilla orchid (yes, the same one we use to flavour all sorts of concoctions), the plant won’t produce a pod (actually the orchid’s seed pod) unless it’s pollinated, and so workers go around their plants to look for new flowers and pollinate them by hand. The flowers only last one day, though, so the task must be completed every day over the roughly three month blooming period or else risk losing some potential crop.

"Orchid Display" by Salihan on Flickr

There’s lots more information I could share, but in the interest of length, I’ll leave it there. All in all, pretty interesting plants. There’s an orchid show every spring up in Ottawa; growers bring their best plants for judging, there are displays of different species and hybrids, vendors have orchids and orchid-related paraphernalia for sale. Imagine the sights and smells! I think this year I’ll try to go.

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3 responses to “Orchids from elsewhere

  1. One day during my trip to the Amazon, our guide led us on a medicinal plant walk. I ended up trailing way behind the group because I was taking photos, so I missed most of his talk, but the thing that I simply could not get over was how many of the native plants we passed were the same ones I’d see in the grocery store for sale! Mostly foliage plants, but even so, it was a real eye opener. It wasn’t until we reached the hotel at the base of the mountain where Machu Picchu is that we encountered orchids. I think many of them had been planted there as part of the landscaping, but they were beautiful. Pity all my photos are slides…maybe some day I’ll get some scanned and will be able to post them.

    • That’s pretty neat, Ellen! I wish that when I was in Ecuador I’d been paying more attention to those sorts of things. I was still naturalist-ically young, and hadn’t really developed my observation skills yet, so I’m sure I missed a lot. I’m looking forward to the opportunity for another visit to the tropics now that I’m paying more attention to things.

      I have piles of film-photos, too, that will likely never be shared because they’re not digital. Slides are at least a little more useful in that you can project them to share them with live groups.

  2. Thanks for sharing your knowlage. Go orchids!

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