The Titillating Sex Life of Orchids

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Orchid flowers make themselves as seductive as possible! Source: thecliparts.com, Clipart Library & pngimg.com

Flowers are all about sex. If they look good and smell good, it’s not to please us humans, but to better seduce their pollinators, because most need cross pollination (transfer of pollen from the flower of one plant to the flower of another of the same species) in order to reproduce. And orchids are the masters of sex when it comes to the world of plants.

How Plants “Do It”

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Wind-borne pollen (here from pine trees) can be so copious it coats everything. Source: www.asthmacenter.com

Many plants (conifers, oaks, grasses, etc.) produce extra-light pollen in copious quantities then liberate it massively into the air so it will be carried away by the wind. They do so in the hopes (yes, I’m going to go a bit anthropomorphic in this blog; it just makes the explanations so much simpler!) that a single pollen grain will accidentally land on a receptive flower of the right species. Wind pollination does work (otherwise, the species that do it would have gone extinct), but what a waste of resources! Sometimes the entire landscape is covered with a thin layer of pollen that will never serve the plant in any way.

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Most insect-pollinated flowers offer an abundant source of nectar to encourage repeat visits. Source: http://www.sarahplusbees.com

Other plants use a more reliable pollinator than the wind—usually an insect, although occasionally a bird (a hummingbird, for example) or a mammal—to carry their pollen from one flower to another. Many essentially offer an open bar: they give as a reward a generous amount of nectar and pollen and are none too picky when it comes to their suitors. Think of the common oxeye daisy, Leucanthemum vulgare, found in fields everywhere. It gives off a subtle, sugary, generic odor that attracts a wide range of insects and its florets just drip with nectar. It likewise produces more pollen that it needs so pollen-eating insects can have their share. The daisy can be pollinated by bees, flies, butterflies, beetles or wasps of many different species.

Scientists have a way of spelling things out quite bluntly and call such blooms promiscuous flowers. (If they hadn’t said it, I would have!) Such plants are counting on the likelihood that one of their many pollen-laden visitors will eventually land on a plant of the same species and that some of the pollen that stuck to its body as it fed will come free and ensure fertilization. That’s still a lot of nibbles and booze (oops, I mean pollen and nectar) to give away, but at least the investment is worthwhile if they achieve pollination.

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The yucca moth absolutely depends on the yucca for its survival (Yucca spp.) and the yucca can only be pollinated by the yucca moth. Source: Google Images

Other flowers are very specific … and orchids are often in this group. Pollinator-specific flowers come in a distinct color or form, have barriers to keep unwanted pollinators out or a scent that is only appreciated by one specific pollinator or at least a limited number of pollinators, thus forming a specific plant-pollinator interaction. A good example among non-orchids is the yucca moth (Tegeticula sp.), which pollinates only yuccas (Yucca sp.). The plant absolutely needs the pollinator and the pollinator can’t get along without the plant. Such plants don’t need to produce as much pollen and certainly not as much nectar as promiscuous flowers … but they usually do have to curry the favor of their pollinators by rewarding them in some way: pollen, nectar, oils, housing, etc.

Orchids, though, are not as charitable as most plants. Although their heavy pollen can’t be carried by the wind and they are almost always pollinated by insects (more rarely by mammals or birds), they are very stingy with their pollen. They don’t produce “quantities” of pollen, only two pollinia or pollen masses (singular: pollinium) per flower. And most are not particularly generous with their nectar either. Indeed, many produce no nectar at all.

Obviously, it’s vital for a flower with only two pollinia that the insect that picks up its ever-so-rare pollen deposits them on another orchid of the just right species. Thus, orchids will go to almost any length to please their specific pollinator, using clever combinations of colors, scents, shapes and textures to better seduce it … but many still don’t feed it!

Deceptive Flowers

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Deceptive orchids trick insects into pollinating them, but offer nothing in return. Source: scarletblack.ca & moziru.com

The way orchids get away with “offeriing the product, but not delivering the goods” is by mimicry. They try to replicate things their pollinator will find attractive: flowers, fellow insects … even rotting meat! They can do this by smell, taste, appearance, texture, etc. Their pollinator visits them expecting one thing, but gets … nothing in return. But it leaves with orchid pollinia glued to its body.

One estimate suggests that of the 20,000 species of orchids, about 8,000 are so-called “deceptive flowers”: they claim to offer something interesting to a pollinator, but don’t deliver. Orchids are not the only deceptive flowers, but they are by far the best at floral trickery.

Let’s look at a few examples:

Seducing the Orchid Bee

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The lip of the bee orchid looks like a female bee, complete with wings, the better to seduce the orchid bee into pollinating it. Source: Ophrys apifera, BerndH, Wikimedia Commons

The bee orchid (Ophrys apifera) is a terrestrial European orchid, also called (I didn’t invent this!) the prostitute orchid. It sets out to seduce a male bee of an appropriate species (different solitary bees in the genera Tetralonia and Eucera). To do so, the bee orchid starts by producing a flower that is physically quite similar to the female of the solitary bee. It has the same color (from a bee’s point of view; we don’t see colors the way they do), is the same size and even offers a similar shaggy texture.

But the coup de grâce is the perfume: the flower releases a pheromone (sex hormone) very similar to that of the female bee, but not quite the same. Tantalizingly different, you might say. Enough so that, if the male bee has to choose between the orchid and a female of his species, he often chooses the orchid!

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Male bee orchid with pollinia stuck to his head. Source: pinterest

When he lands and tries to copulate with the flower, his movements release the flower’s pollinia that end up literally glued to his head. Frustrated by the flower’s lackluster response, though, he leaves.

Bees may not be very intelligent, but they do learn. As a result, he’ll avoid the next few bee orchid flowers he encounters, remembering the disastrous results of his initial flirtation. But the further away he gets from the original flower, the more his memory fades and soon enough, he’s ready to try again. By now, though, he’s at a considerable distance from the original plant and this ensures that the cross-pollination that occurs will be between plants that are genetically distinct, thus avoiding any consanguinity. Just what the orchid wants!

When he lands on the new flower, the pollinia, if he’s wearing any, get caught in structures in the flower and are literally ripped from his head, then replaced by new ones.

Let’s hope he eventually finds a sweetheart of his own species before he dies of exhaustion!

The bee orchid is hardly an exception. Many orchids mimic the scent of female insects and induce the pseudo-copulation of males for their own reproductive purposes, but few mimic the appearance of the female quite as well as the bee orchid.

A Swarm of Pseudo-Bees

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The pretty flowers of many Oncidium orchids are designed to look like a swarm of bees. Source: sitecgdw.com

Some species of Oncidium in South and Central America have flowers that subtly mimic the appearance of local bees (genus Centris), but it’s not for the purpose of sexually attracting them. The small flowers are grouped in large numbers on arching stems that move in the slightest breeze, even to the point of seeming to shake.

Male Centris bees are very territorial by nature, and when they see what seems to be a swarm of dancing bees invading their space, they go on the attack, repeatedly dive-bombing the flowers … and when they do, they pick up pollinia by accident. After the exhausting but fruitless attack, they pull back, then discover another “flowery swarm” elsewhere, and attack that too, dropping off pollinia from the first orchid, thus ensuring fertilization, and picking up fresh pollinia. And before they learn better (and they will), this can happen four or five times, leaving the orchids pregnant and happy and the bees confused and frustrated.

Lady’s Slippers

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The swollen pouch of a lady’s slipper orchid (here, Cypripedium pubescens) is actually an insect trap … and part of an elaborate pollination scheme! Source: D. Gordon E. Robertson, Wikimedia Commons

Deceptive orchids aren’t limited strictly to the tropics. The beautiful lady’s slipper (Cypripedium spp.), found, in one form or another, throughout much of the Northern Hemisphere, even in the boreal forest … is definitely on the list of deceptive flowers. In other words, she really isn’t much of a lady!

Its lip, a mutated petal in the shape of a pouch, gives off a honeyed smell that implies an abundant supply of nectar. The insect (a fly, bumblebee or solitary bee, depending on the species of lady slipper: each has its own favorite) lands on the lip looking for the promised nectar. It wanders towards the greatest intensity of scent … to discover itself on the smooth inner surface of the lip. Thus, it slips to the bottom of the pouch where the sweet scent is strongest, figuring it has hit the jackpot, but no, there is no nectar at all. Worse, when it tries to leave, there are downward inclined hairs that prevent it from going back the way it came. The insect is now a prisoner.

Eventually, it discovers an opening at the bottom of the flower and tries to wriggle its way out. In doing so, it drops off any pollinia it was carrying from a previous lady slipper encounter, thus ensuring pollination, but the exit hole is so arranged that, when it does it free, new pollinia are automatically glued to it.

The lady’s slipper orchid is far from the only orchid to use this technique. It’s a fairly common ploy among deceptive orchids.

Stinky Blooms

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The disgustingly scented flowers of Bulbophyllum phalaenopsis look and smell like rotting meat so as to better seduce their carrion fly pollinator. Source: C T Johansson, Wikimedia Commons

The gigantic orchid Bulbophyllum phalaenopsis will surely never win any beauty contest. It has to have just about the ugliest flower of any orchid.

Its 15 to 20 reddish-purple flowers look like rotten meat and swarm with fleshy projections said to look like wriggly maggots. In addition, it emits a truly nauseating odor, one said to replicate the stench of a thousand dead elephants rotting in the sun. It does so to attract a female carrion fly looking for a place to lay her eggs. (This is called “brood site deception.”) As she does so, she inadvertently picks up the flower’s pollinia, then carries them off to another flower. When the fly’s eggs hatch, they simply die: there’s nothing there they can actually feed on.

Again, Bulbophyllum phalaenopsis is not alone. Many orchids, including the those in the foreboding-sounding Dracula genus, likewise attract carrions flies with an odor that seems unbearable to our nostrils, yet so enticing to flies!

Flower Mimics

Not all orchid flowers mimic female insects, marauding bees or dead elephants. Many disguise themselves as other flowers.

When an abundant plant has found the key to success with pollinators, it’s far from uncommon for a local orchid to learn to imitate it to take advantage of its pollinators.

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One of these three flowers is deceptive: it has nothing to offer its insect pollinators. Source: Guérin Nicolas, Mercewiki et Dick Culbert, Wikimedia Commons

In South and Central America, for example, there is a milkweed (Asclepias curassavica) and a lantana (Lantana camara) both of whose flowers share the same color combination (orange with a yellow center) and also the same pollinators—notably specific species of wasps and butterflies—and the two produce abundant nectar to ensure their favorite pollen carriers visit faithfully and thus transfer their pollen. However, a few species of Epidendrum—including E. radicans—have learned to mimic them by producing flowers of exactly the same colors … but with the difference that these orchids offer no reward whatsoever. The insects visit, pick up their orchid’s pollinia, and leave hungry and confused, the promised nectar simply being absent.

Again, there are hundreds of other orchids that mimic other flowers so they can “steal” their pollinators. It’s just something orchids do!

50 Shades of Orchid Sex

Obviously, there are many other deviations in the twisted sex life of orchids that I could have told you about:

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A trigger mechanism in the flower of a Catasetum shoots pollen with such force it can stun the pollinating bee. Source: catasetum-ian.blogspot.ca

  • A Catasetum that shoots its pollinia onto the head of its pollinator with such force that it is sometimes knocked unconscious or even killed by the experience;
  • Darwin’s orchid (Angraecum sesquipedale) so badly wants to preserve its precious nectar from nectar thieves that it stores it at the bottom of a one foot (30 cm) spur so that only its exclusive pollinator, a moth called Xanthopan morgani praedicta, whose probiscus is just long enough, can reach it;
  • Holcoglossum amesianum which, if its preferred pollinator doesn’t show up, self-pollinates in such a very physical way that I wouldn’t dare to describe it in a blog that could be easily read by children;
  • And many more!

Decidedly, orchids are the vixens of the plant world … and they seduce humans too! After all, what do we do when so they shamelessly offer themselves to all and sundry with their sultry flowers, but take them from the wild and grow them in our homes and gardens!

Sex sells: it always has!20180115A thecliparts.com, Clipart Library & pngimg.com

Christmas Plants Around the World

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Christmas plants differ according to region. Source; laidbackgardener.blog

The most popular Christmas plant in North America is certainly the poinsettia (Euphorbia pulcherrima). There is scarcely a store that doesn’t sell them or a home that isn’t decorated with one. But there are other Christmas plants, including Christmas cactus (Schlumbergera spp.), Christmas kalanchoe (Kalanchoe blossfeldiana), amaryllis (Hippeastrum spp.), Christmas pepper (Capsicum annuum), Jerusalem cherry (Solanum pseudocapsicum), frosted fern (Selaginella martensii ‘Frosty’), Norfolk island pine (Araucaria heterophylla) and, more recently, wintergreen (Gaultheria procumbens).

Christmas trees are popular all over North America, too. Fir trees (Abies spp.) are the biggest sellers, but Douglas firs (Pseudotsuga menziesii), spruces (Picea spp.) and pines (Pinus spp.) are widely used.

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Christmas fern (Polystichum acrostichoides). Source: Krzysztof Ziarnek, Kenraiz

The Christmas fern (Polystichum acrostichoides) was once commonly used in Christmas wreathes, garlands and centerpieces in Eastern North America, as it has evergreen fronds that last all winter and are thus available at Christmastime, but its star has waned considerably. It’s just too easy to find longer-lasting artificial or preserved foliage for such use these days. The Christmas fern still makes a great garden plant for shady spots and is hardy to zone 3.

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Winterberry (Ilex verticillata Berry Poppins®). Source: Proven Winners

The branches of winterberry (Ilex verticillata) have fared better over time and are still widely used. This deciduous holly, native to eastern North America, is leafless at Christmas, but its branches are covered with bright red berries that create great swaths of color in Christmas arrangements. You can grow them yourself (the shrub is hardy to zone 3 and you will need to include at least one male plant in your planting to pollinate the berry-bearing females), but you can also buy branches in florist shops … including fake ones, unfortunately.

That covers most of the plants associated with Christmas in North America, but Christmas plants differ around the world. Let’s take a look at what’s going on elsewhere.

Europe

In general, the plants featured in the first paragraph—poinsettias, Christmas cactus, Christmas kalanchoe, etc.—are also popular in Europe, although the poinsettia, even though it is not rare per se, is not as popular as on this side of the Atlantic. But there are other plants associated with Christmas (and New Year’s Day) that are more specific to Europe.

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Holly (Ilex aquifolium): more popular in Europe than in North America. Source: AnemoneProjectors, Wikiimedia Commons

For example, holly (Ilex aquifolium) is a European shrub or tree with spiny-edged, shiny, leathery, evergreen leaves and red berries and is grown in many Old World gardens. True enough, holly is available on a limited basis in North America too (although are mostly seem either on Christmas cards or as sprigs of plastic leaves), but nothing to the extent to which it is used in Europe, where, in some countries, sprigs of holly are found on nearly every window ledge and doorway. This tradition has come to be seen as a sign of welcome, but is in fact based a centuries-old belief that putting holly on all possible entranceways would prevent evil spirits from invading the home.

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Mistletoe is no longer as common as it once was. Source: mistletoematters.wordpress.com

Kissing under the mistletoe during the Christmas season is a very old European tradition and can be traced back to the time of the Druids, who laid down arms and exchanged greetings under the mistletoe, considered to be a very sacred plant. Mistletoe is a parasitic plant that grows on tree branches, counting on sap it absorbs from its host for its survival. European mistletoe (Viscum album)—with its translucent round white berries—is the original variety to kiss under.

The tradition of kissing under the mistletoe was brought over to the New World and thrived for awhile, but now appears to be dying out. Certainly mistletoe is now only available very locally in North America: I haven’t seen a sprig of it in years! It’s still widely used in Europe during the holiday season.

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English ivy (Hedera helix) used in a wreath. Source: bcinvasives.ca

English ivy (Hedera helix) is a traditional Christmas plant in Europe, widely used in holiday garlands and wreaths. Think of the carol The Holly and the Ivy, for example. And why not, since this evergreen climber grows abundantly everywhere on that continent and so is readily available! The tradition of using ivy as a Christmas decoration never caught on in North America, probably because ivy is neither native nor widely grown, though it has escaped from culture to become abundant in a few areas. Harvesting ivy for Christmas decorations is something that could be encouraged as a control measure in areas (mostly on the US West Coast) where ivy is proving to be a pernicious weed.

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The Christmas rose (Helleborus niger) is a stunning early bloomer… but only blooms at Christmas in mild climates. Source: 4028mdk09, Wikimedia Commons

The Christmas rose (Helleborus niger) is not a rose (Rosa spp.) at all, of course, but a perennial. It’s a traditional Christmas plant in southeastern Europe, notably in areas where Orthodox Church is the common religion. Orthodox Christmas takes place about two weeks later than in Western rites, around January 7. And this very early perennial is usually in bloom by then. Although mainly used in flower beds or naturalized in woodlands, it’s also sold as a gift plant at that season.

Elsewhere in Europe and pretty much everywhere in North America, this plant flowers too late to be a Christmas plant. Where I live, it isn’t even in bloom at Easter … it’s more like a Mother’s Day plant!

In Europe, the tradition of Christmas trees is well established and often spruce or pine, or even a juniper or other conifer, are used, depending on what is available locally.

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The Yule log tradition has trouble surviving in modern homes, as so many no longer have a functioning fireplace. Source: maeclair.net

The tradition of the Yule log has largely died out in Britain and Central Europe as it has in North America, but in many parts of Europe, notably in Scandanavia and Eastern Europe, it remains deeply entrenched. A Yule log is a very large hardwood log, the idea being to light it on Christmas Eve and have it burn through the night and Christmas Day. In the Balkans, the Yule log is called a badnjak (or budnik, according to the local language) and it is usually an oak, a symbol of longevity. Those who do not have a fireplace to burn a log in often decorate their apartment with twigs of oak.

In France, Belgium and Switzerland, the Yule log (bûche de Noël) has morphed into a log-shaped cake, traditionally served at Christmas … you don’t need a fireplace for that!

Mediterranean and Middle East

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A wreath decorated with pomegranates (Punica granatum). Source: www.clubbotanic.com

The main Christmas plant in this region is the pomegranate (Punica granatum): a perfect choice, as it matures at just the right time of year. Doors, fireplaces, tables, etc. are decorated with pomegranate fruits, both fresh and artificial.

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Butcher’s broom (Ruscus aculeatus). Source: Dominicus Johannes Bergsma, Wikimedia Commons

Two other plants often used in Christmas decorations are the shrubs butcher’s broom (Ruscus aculeatus) and firethorn (Pyracantha spp.), both bearing evergreen foliage and red berries.

In Israel, olive branches (Olea europaea) are offered at Christmas to friends as a symbol of peace.

Mexico

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Flower market full of poinsettias (Euphorbia pulcherrima) in Mexico just before Christmas. Source: casita-colibri.blog

The poinsettia (Euphorbia pulcherrima) is native to Mexico and is popular in there, where it’s known as flor de Nochebuena (Christmas Eve flower). Butcher’s broom and firethorn, brought over from Spain, are also popular, as well as are several local plants that bloom at Christmas.

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Traditional Mexican Christmas punch with floating manzanitas (Crataegus mexicana). Source: http://www.goya.com

Manzanita, also called tejocote or manzanilla (Crataegus mexicana), a large-berried hawthorn, is another plant traditionally used as a Christmas decoration in many parts of Mexico and Central America. The orange fruits may be threaded onto a garland and are also used to make Christmas punch.

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Display of radishes on the Noche de Los Rábanos. Source: AlejandroLinaresGarcia, Wikimedia Commons

One of Mexico’s most curious Christmas traditions, however, is the Night of the Radishes (Noche de Los Rábanos), celebrated in the region of Oaxaca on December 23rd. In it, radishes are carved and arranged into some very impressive displays.

South America

Since most of this continent lies south of the equator, the seasons are inverted and Christmas takes place in summer, not winter. That means traditional Christmas plants of the Northern Hemisphere bloom six months too late for Christmas. As a result, the poinsettia is called “Easter flower” (flor de pascua) in many South American countries, because it blooms at Easter, while our Christmas cactus (Schlumbergera) is called “flor de maio” (May flower) in its country of origin, Brazil. Yet there is a Christmas cactus in these countries. The plant we call Easter cactus (Hatiora gaertneri, formerly Rhipsalidopsis gaertneri) in the North is the “cactus de Navidad” and blooms at Christmas in much of South America.

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Colored berries of the Brazilian peppertree (Schinus terebinthifolius). Source: Javier Alejandro, flickr.

South Americans tend to use native plants as cut flowers or holiday plants at the Christmas season. Branches of the Brazilian peppertree (Schinus terebinthifolius) and its cousin, Peruvian peppertree (S. mollis), known in the north for the pink peppercorns they produce, are often used to decorate churches and houses during the holiday season, as they are loaded with small red berries at that time of year.

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Venezuelan Christmas orchid (Cattleya percivaliana). Source: QuazDelaCruz, Wikimedia Commons

Venezuela has its own Christmas orchid that blooms for the holidays: Cattleya perciviliana. Elsewhere in South America, the usual “orquídea de navidad” is Angraecum sesquipedale, actually native to Madagascar, but widely grown for its large white star-shaped flowers. It’s also called estrella of Belén (star of Bethlehem), but then, so are many other white, star-shaped flowers, including bulbs of the genus Ornithogalum.

In Paraguay, house and Christmas displays are often decorated with “flores de coco,” the long, fragrant inflorescences of a local palm tree, the coyol (Acrocomia aculeata). This pre-Christian tradition comes from the indigenous Guarani people.

Asia

In general, the concept of Christmas is relatively new to this continent and the celebration is mostly a commercial one of American inspiration, so there are often no traditional plants associated with the holiday, at least not long-standing ones. Most are the same Christmas plants seen in North America (poinsettias, Christmas cacti, etc.). Christmas trees, almost nonexistent only 30 years ago, for example, are now seen everywhere, although more often in shopping centers than in private homes. Usually artificial trees are used.

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Heavenly bamboo (Nandina domestica). Source: http://www.mailordertrees.co.uk

The Christian population in Japan is more firmly established than most in Asia and has solidly adopted the tradition of the Christmas tree, usually a real fir or spruce tree. Heavenly bamboo, Nandina domestica, which is not a bamboo at all, but a shrub, is the second-best-known Christmas plant, with its scarlet fruits and red winter leaves. Chrysanthemums (Chrysanthemum morifolium), popular in all seasons in Japan, are widely used at Christmas too.

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Apples stamped with seasonal messages are common Christmas Eve gifts in China. Source: gbtimes.com

In China, an apple wrapped in colored paper or stamped with an appropriate seasonal message is often offered as a gift on Christmas Eve because the word “Christmas Eve,” translated as “night of peace” (Ping’an Ye) in Mandarin, sounds like the word apple (píngguǒ).

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Christmas palm (Adonidia merrillii). Source: palmpedia.ne

In the tropical regions of Asia, the Christmas palm (Adonidia merrillii), better known by its old name, Veitchia merrillii, is widely grown. With its stocky trunk and relatively short fronds, it looks like a dwarf royal palm … and bears bright red fruit at Christmas. Originally from the Philippines and Malaysia, this palm is now grown throughout the tropics.

Finally, in India, the golden Monterey cypress (Cupressus macrocarpa ‘Goldcrest’) is growing in popularity as a Christmas tree, but otherwise, Christmas is little celebrated in India.

Africa

The traditions of using Christmas plants are more firmly established in South Africa than in the center and north of the continent, brought to this region by European settlers (notably the Dutch and English).

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To Northeners, hortensias (Hydrangea macrophylla) just don’t say Christmas, but it warms the cockles of the heart of South Africans. Source: pxhere

Again, though, with the seasons being inverted, the South African Christmas plants are very different from those in the Northern Hemisphere. Notably, the hortensia (Hydrangea macrophylla), well-known in the North for its summer bloom, is called “Christmas flower” and is by far the most popular Christmas plant!

On the other hand, poinsettias are catching on as well. They have to be specially prepared in order to bloom at Christmas rather than in May, which is when they’d bloom if left on their own. Local nurserymen manage to do this by covering their production greenhouses with black cloth after 4 pm to ensure the short days necessary to stimulate bloom.

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Christmas bells (Sandersonia aurantiaca) are bulbs native to South Africa. Source: http://www.alanjolliffe.com

Various native plants also serve as Christmas plants, such as Christmas bush (Pavetta spp.), Christmas bells (Sandersonia aurantiaca) and Christmas berry (Chironia baccifera). Several plants imported from Australia, which has a similar climate, are also appreciated for their winter bloom. You’ll read more about those below. Africans also celebrate Christmas with many plants that are for us just typical summer flowers, like daisies, roses and zinnias.

Christmas trees are very popular in South Africa, but they use as subjects conifers adapted to local conditions, such as cypress (Cupressus spp., including C. macrocarpa), Japanese cedar (Cryptomeria japonica) and various pines (Pinus spp., including P. radiata).

Australia

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The Norfolk Island pine (Araucaria heterophylla) is Australia’s favorite Christmas tree, AlfredSin, flickr

In Australia, the traditional Christmas tree is the native Norfolk Island pine (Araucaria heterophylla). Grown in mostly as a houseplant in the northern hemisphere, where it rarely exceeds 5 feet (1.5 m) in height, in Australia, it can eventually reach up to 250 feet (65 m) in height, about 20 floors! Other mild-climate conifers from various parts of the world are also used as Christmas trees, including various pines.

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The Australian Christmas tree (Nuytsia floribunda). Source:  JarrahTree, Wikimedia Commons

And Australians have their own Ozzie Christmas tree, Nuytsia floribunda … but it’s not a conifer, but rather a broad-leaved tree. Moreover, it’s a parasitic tree (or rather hemiparasitic tree, since it does carry out its own photosynthesis) that steals most of its water and minerals from nearby plants! The Australian Christmas tree produces frothy spikes of orange-yellow flowers just in time for the holidays.

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One of many Christmas bushes in Australia: Ceratopetalum gummiferum. Source: gdaymateowyagoin, flickr

To add to this, each Australian state seems to have its own “Christmas bush,” always a shrub that produces masses of either flowers or colorful fruits at the right season, including Correa spp., Chromolaena odorata, Ceratopetalum gummiferum and Prosanthera laisanthos. Also, there are many bulbs that bloom at Christmas, including various species of Blandfordia, called “Christmas bells.” And Australia also has its own Christmas orchid: Calanthe triplicata, native to the north of the country

New Zealand

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New Zealand Christmas tree (Meterosideros excelsa). Source: Ed323, Wikimedia Commons

Mention Christmas tree to any New Zealander and they’ll immediately think of Meterosideros excelsa, a rounded broadleaf tree with feathery red flowers at Christmas. It’s called the New Zealand Christmas tree or pōhutukawa. And an introduced bulb from South America (Alstroemeria psittacina), with green-tipped red tubular flowers, has “gone native” and is well-known by locals as New Zealand Christmas bells.


So, wherever you travel around the world, there are always interesting Christmas plants to discover!

If you know of other Christmas plants, do not hesitate to let me know about them at laidbackgardener@gmail.com.20171224A HC.jpg

Darwin’s Orchid

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Darwin’s orchid (Angraecum sesquipedale) with its long spur.

I just saw, for the first time in my life, Darwin’s orchid (Angraecum sesquipedale). That was at the annual show of my local orchid society (Les Orchidophiles de Québec), held on April 8 and 9, 2017. It was labelled, but it didn’t need to be. I’ve known about this orchid since I was a teen and avidly read everything I could find about evolution. I recognized it immediately. And how could you fail to notice it? It’s has large white flowers… but more importantly, it’s unique in that it has a long downward-hanging green spur that projects behind the flower.

It’s certainly attractive enough, but its history is even more fascinating.

A Surprising Discovery

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Louis-Marie Aubert of Petit-Thouars. Illustration: Wikimedia Commons

In 1798, the French botanist Louis-Marie Aubert of Petit-Thouars discovered in Madagascar an orchid with large white flowers bearing a very long spur. He only named the plant 25 years later, in 1822, calling it Aeranthes sesquipedalis, later changed to Angraecum sesquipedale. Angraecum comes from the Malay word for orchid, “angrek”, while sesquipedale refers to the very long spur and means “a foot and a half” (45 cm). Indeed, the spur ranges from 10.6–16.9 in (27 to 43 cm), just short of 1 ½ feet (45 cm). If you include the distance from the tip of the spur to the tip of the flower’s lip from which it extends, that would indeed make “a foot and a half”. It it by far the longest spur found on any flower.

Darwin Makes A Prediction

Charles Darwin in 1881

Charles Darwin studied and wrote about

In 1862, a British orchid enthusiast James Bateman sent Charles Darwin, the famous scientist and father of modern biology, blooming specimens of this orchid to Charles Darwin… and he was immediately fascinated.

You see, in flowers, such a spur, also called a nectary or a nectar spur, is a projection of the flower that contains a sugary liquid called nectar… and a flower only produces nectar to attract a pollinator. Thus an insect or other pollinator needs to have some means of reaching into the spur to suck up the nectar and, in so doing, picks up pollen which, one hopes, it will then deposit when it visits another flower of the same species.

But only insects with a long proboscis, a bird with a long beak or an animal with a long tongue have access to flower spurs. That way the plant ensures a certain fidelity in its pollination: it pre-selects pollinators, eliminating those less likely to ensure its fecundation.

But the extremely long spur of Angraecum sesquipedale only contains nectar in the last few centimeters of its extremity. Why was nectar placed so far from the flower’s anthers and stigma, where pollination takes place?

Darwin guessed almost immediately. He quickly began dissecting flowers and testing the mechanism necessary to reach the nectar and release the pollen. He soon announced that it was now certain that in Madagascar there had to be a moth with a proboscis ten to eleven inches (25 to 28 cm) in length and which would then be able to reach the nectar at the base of the spur. If he predicted it would be a moth, that’s because the flower was white and gives off an intense scent only at night, a combination of traits only moths find appealing.

The prediction is greeted with much skepticism by the scientific community of the time. But it turns out Darwin was correct.

The Prediction Comes True

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Darwin’s sphinx moth (Xanthopan morgani praedicta). Photo: Esculapio, Wikimedia Commons

In 1903, 40 years later, and well after the death of Darwin in 1882, such a moth was indeed identified. Darwin’s sphinx moth (Xanthopan morgani praedicta, now Xanthopan morganii) has a long proboscis that it carries coiled. The sphinx first approaches the flower, attracted by its odor, then once it has inspected it, backs up about a foot (30 cm), extends its proboscis, then inserts it into the spur as far as it will go. It’s a bit of a struggle, so it pushes hard against the flower, thus inadvertently picks up pollinia (masses of pollen) that it will later carry to another Darwin orchid, ensuring its fecundation.

Interestingly, even in 1903, the relationship could only be postulated: no one had yet actually seen a Darwin’s sphinx moth pollinate an Angraecum sesquipedale flower. That didn’t happen until… 1992, nearly a century later!

Darwin’s sphinx moth is the only pollinator of what is now called Darwin’s orchid. The two are believed to have co-evolved, each adapting to the shape of the other to ensure a perfect symbiosis.20170412A

Isn’t nature marvelous?20170412A