Orchidarium 5

The ongoing saga of adapting a purchased Wardian case as an intermediate temperature orchid growing case, my orchidarium.

The configuration in the picture is temporary, with plants more or less hanging from the roof or sitting on the bottom in places that will help me gauge light preferences. The large piece of grapewood to the left is in its final position and has one plant (Specklinia grobyi) permanently placed. 

The lighting is now solved, after some fits and starts. A combination of 40 watt and 90 watt LED lamps gave too MUCH light, so I have scaled back to 2 of the 40 watt lamps (Kessil Tuna Sun A160WE), both shining through a glass plate in the roof so that waste heat stays outside the case. Happily, the structural parts of the orchidarium are now complete - vent fan, internal fans for air flow, and lighting. I do all the watering by hand with a pump-up spray bottle; the case is small and this only takes about one minute. I do the main watering in the morning and a quick misting at night when the lights go out. Almost all of the plants are now thriving.

I have several large pieces of rot-resistant grapewood burl (bloomsandbranches.com) that are beautifully natural and have a nice texture for orchid roots. The source says that they are sandblasted but otherwise untreated. You can see some of them in the picture above. I played around with various methods of situating them in the case. I tried bolting them together and sitting them on the bottom, but that isn't easy because the wood is so irregular and is filled with unexpected pockets and layers so screws don't hold well. I did get some of the core parts bolted together to make a base. I tried just leaning them up against the glass, but that is not very stable and limits the way they can be arranged. Finally, I stumbled on using the fact that the roof of my case is steel and that very strong neodymium magnets are inexpensive: I am hanging the grapewood from magnet hooks attached to the inside of the roof. My mounting wood is itself epiphytic! I drill small holes near the top of the wood and thread wires through them and the hooks. Black nylon-coated fishing leader wire is perfect - strong and nearly invisible. This method is simple, easy, and very flexible because I can move the magnets around and change the lengths of the suspension wires easily. If you have a case that does not have a ferromagnetic roof, you could achieve something close by drilling holes and inserting hook bolts or stringing guy wires that you can hang things from. Grapewood burl is fairly light but a piece can weigh up to a few pounds, and then there are the plants and water weight, so you would need a roof with considerable strength. Fortunately mine came with that.

Mounting orchids directly to the grapewood is finicky work though fairly easy. It is awkward threading monofilament line around the pieces of wood when in place, and tying knots in that stuff seems to require three or more hands, making me wish once again that we were bipeds evolved from hexapods. An alternative is to use Super Glue, but that makes white deposits that are glaring and very hard to get rid of or camouflage. The monofilament is hard to see and when the plant is established it can be removed. Partly because I am not very patient with finicky work, but also because the final mounted position of the plant ideally is gotten right the first time, I am doing this part very gradually. Okay okay, I have mounted ONE plant directly to the grapewood so far. But it is lovely!

The light intensity across the cabinet is extremely wide ranging, which is good for plant diversity but challenging for placing individual plants. What seems to be working fine, but is very slow, is hanging or sitting a plant on the original mount or pot in some location that I think will work, and then waiting a month or two to see if it thrives. I have found that most of the cloud forest orchids I have in the case get a purple flush or spots on their leaves well before getting dead sunburn patches as I am used to for windowsill plants. One plant (Lepanthes gargoyla) went from being dark green to bright purple in about a month. Often the purpling starts within a day or two. When that happens, I back off a bit until I get a spot where the leaf color looks correct for the species; some are supposed to be purple, but not many. I have tried to use a cell phone light meter but damned if I can get the readings to match what the plants are telling me. I have spots where the light meter says 200 footcandles and a plant that is said to like 500-1,000 footcandles turns purple within days. I don't think my light spectrum is weird - these lamps are designed for plants and the orchids once situated well are clearly happy. I think the cell phone light meters are inaccurate at low light levels. So I use the plants as my guide.

For orchid growers used to things like Cattleya or Phalaenopsis (each new leaf is cause for celebration), many of the plants you can grow in an orchidarium are fast fast fast! Sometimes, when I get a plant such as a small Masdevallia or Pleurothallis in just the right spot in the case, the plant will start firing out new leaves and flower spikes like mad. Well, the orchid version of "like mad", which is not quite tomato plant mad. For example, I have a Masdevallia sernae plant (reputed to be easy to grow) with about 10 leaves that sat like a lump for 6 months, and within a month of getting the right conditions (mostly lighting), shot out many new roots and at least 10 new leaves. This is a bit extreme, but something of the sort is common. Some of the plants flower and grow nearly continuously, with sequentially flowering spikes that pump out flower after flower for a year or flushes of single-flowered spikes coming in every month or two. True, everything is on a small scale, but for sheer cultural abundance and gem like beauty they are incomparable. I particularly like my two Scaphosepalum plants (S. breve and S. aff. swertifolium, which means it is swertifolium or something very similar) - both are sequential bloomers and as one flower passes the next one is already forming, with elaborate curls and protrusions swelling and morphing gradually into the final flower form. The flower buds are just as fun to look at as the open flowers, and the final flower is a three-dimensional fantasy landscape, nearly impossible to photograph.

The Poetry of Dendrobium moniliforme (Choseiran)

Dendrobium moniliforme, called Sekkoku or Choseiran in Japan, is a small caning Dendrobium that has been cultivated for centuries in Japan. Though less well known in the west than its botanical second cousin Vanda (Neofinetia) falcata (Furan or Fuukiran), Dendrobium moniliforme also has an extensive history in Japan of appreciation and selection of botanical varieties. There are various cane heights, cane colors, leaf shapes, leaf colors and variegations, and flower colors. As with Vanda falcata, a few of them are just plain weird, but most of the varieties are lovely little plants.

I have quite a few Vanda falcata but I resisted purchasing Dendrobium moniliforme because they looked kind of ragged and leggy, as caning Dendrobiums are wont to be. A short while ago I purchased a D. moniliforme 'Kosetsu' plant, a fairly typical white flowered variety with plain green leaves and canes, probably not much different from the common wild form other than being on the small side. It was love at first sight. A simple description of my plant or even the photo below fails to convey what enchanted me, but I will try to give you a sense with a prose poetic description (please forgive my amateur attempt).

A stand of ancient trunks densely clustered on a hill, clothed in papery wrapping, shredded and worn, revealing smooth maroon skin. Most are proudly erect, but one kinks a bit as if staggering under the weight of age. In the midst of the ancient ones, two vibrant green youths stand tall, shouting with exuberance, their skin green and tight on their canes and their leaves tender and graceful, unaware that they will soon shed their leaves and join the ranks of the ancient ones. In time, the ancient ones will bear pristine white scented flowers for a few weeks, and then will return to their mute and papered form, each year becoming more shriveled and shredded until they can bear flowers no more. In a month or a year, new youthful canes will push up and exclaim in green that life endures, life persists, life prevails.

That is what my plant says to me. Though I can find very little English literature on the plant, it seems likely to me that similar sentiments are found in Japanese. This is the bonsai of orchids.

Oncidium sotoanum, Orchid of the Month, September 2017

Oncidium sotoanum (known for a long time as O. ornithorhynchum, but recently subject to one of those annoying "precedence" squabbles that seem to be so important to some) is a moderately large plant with a typical Oncidium growth habit: large flattened pseudobulbs, long thin-textured leaves, and seasonally large branching panicles of small flowers. It is reported to grow in northern Central America in humid tropical rain forests at elevations up to 1500 meters. The species is most famous for its strong sweet fragrance, variably described as vanilla, chocolate, or Fruity Pebbles cereal. I would prefer to say that Fruity Pebbles cereal (one of the many triumphs of American marketing, with the goal of making money by damaging the health and aesthetics of world youth - go marketers!) smells like Oncidium sotoanum.

Specimen Oncidium sotoanum plant grown as an ornamental.

Though the Oncidium sotoanum flower is lovely and smells divine, the species is probably better indirectly known for hybrids in which it dominates, including Oncidium Sharry Baby and Oncidium Twinkle. Both of these hybrids have flower panicles and flowers that resemble O. sotoanum except for color, and both are among the most famous hybrids in the orchid grower's world for their scent.

Presumably this famous scent is intended to attract pollinators, probably male Euglossine bees, which are scent collecting bees often associated with orchids. The scent oils in O. sotoanum are produced by specialized flower cells called elaiophores (from ancient Greek "oil bearer") which form the surface of ridges and pillars near the base of the lip, easily visible in the photo below. This part of the lip is a contrasting yellow or orange color, presumably as a cue to bees in locating the oil. The orchid's purpose, as usual, is to attract and then position these bees so that they pick up and drop off pollinia. Unlike many orchids, this one provides something that the bees want (they in turn use the oils to attract female bees, but that is another story).

Single Oncidium sotoanum (with the old species label) flower, showing the yellow-orange callus where scent oils are produced - notice its proximity to the pollinia, which are not visible but are adjacent to the white patch just above the callus. Photo from IOSPE (Jay Pfahl).

This flower along with many others raises an interesting question: why do so many flowers smell good to humans? Not all do of course, witness the famous corpse flower and many similarly scented flowers, intended to attract carrion flies. However, I think it is fair to say that a randomly chosen scented flower will smell pleasant, or at least intriguing, to most humans. Clearly this has nothing directly to do with us - these flowers have evolved to produce a huge variety of volatile compounds to attract pollinators, usually insects, bats, hummingbirds, and the like, but certainly not humans. It is hard to avoid, but also hard to prove, the conclusion that we have evolved to like the scent of flowers and not the other way around. But why? We don't eat them, we don't defend ourselves with them, indeed they seem altogether useless in every way except aesthetically. Perhaps humans evolved to like the scent so that individuals could pick them and elicit sex by presenting them to their amorous choice, much like Euglossine bees? Certainly that is one of their primary uses in current cultures, although rarely stated so baldly. I suppose this is just barely plausible, though it seems a stretch. More likely, flowers act as cues for the eventual location of fruit, a favorite food of a wide variety of monkeys and apes, including us. Hard to test, but fun to think about. Meantime, if you grow orchids, get this species or one of its hybrids - they smell divine.

Pesticides: 100% all natural

Here is a topic that generates a lot of heat and little light. The conventional view among the liberal crowd that I mostly hang out with is that natural is good and man-made is bad. This view is laughably ignorant and sometimes downright dangerous. It is perfectly sound to assess the safety of chemicals, for humans and for other animals and plants, both short term and long term. The ignorance comes with the idea that natural is safe and unnatural is not. In fact, the safety of any product has to be assessed regardless of origin.

If this raises your hackles, let me tell you a story. When I was a kid, one of the home remedy ways to treat my cacti for insects was to exhale cigarette smoke under an inverted jar with the cactus under it, and let it sit for some time (not that I actually did this, but I read about it). Now this is a perfectly sensible method - tobacco smoke contains nicotine, which is a very effective broad spectrum insecticide. Indeed, it is thought that tobaccos (and related plants) make nicotine to kill their insect pests. On a larger scale, nicotine was a major agricultural pesticide from about 1945 through 1980. Nicotine is all natural and totally "organic", but it has a problem - to mammals it is acutely poisonous. The only reason cigarette smokers don't drop dead after a few puffs is because tobacco smoke contains only small amounts of nicotine. Though it was never banned in the U.S., it is no longer in use as a pesticide because of its toxicity.

Here is a (very) partial list of other 100% all natural chemicals that are very hazardous in some way, with their broad class of toxicity and natural source in parentheses: aflatoxin (carcinogen, fungus), ergot alkaloids (neurotoxin, fungus), ricin (cytotoxin, plant), aconitine (neurotoxin, plant), arecholine (neurotoxin, plant), atropine (neurotoxin, plant), scopolamine (neurotoxin, plant), amanitin (cytotoxin, fungus), coniine (neurotoxin, plant), delsoline (neurotoxin, plant), colchicine (cytotoxin, plant), anabasine (neurotoxin, plant), ptaquiloside (carcinogen, plant), ouabain (cardiotoxin, plant), strychnine (neurotoxin, plant), morphine (neurotoxin, plant), and last but not least botulinum toxin (neurotoxin, bacterium), which is the most acutely lethal toxin known (in humans, about 100 nanograms is lethal when injected, a speck of the chemical too small to see by eye). And I am leaving entirely out of the list toxins produced by animals for hunting (snakes, cone snails, and many others) or defense (poison arrow frogs and many others), and irritants (urushiol from poison ivy being the most famous in the U.S.).

All of the above listed chemicals are most likely produced defensively, to prevent contact with or ingestion of the producing organism. They are the product of evolution, which has had notably outstanding success at producing toxins because they are so useful as defensive and offensive weapons. Most of the plant chemicals probably have insects as their main target, because they are the most damaging herbivores. However, in most cases all complex animals share with insects the target of the toxins, so they are often toxic to varying degrees to many or most animals.

This is not to say that man-made chemicals aren't dangerous - everyone is well aware that we have contributed our own ingenious toxins to the huge panoply of natural toxins, sometimes with more enthusiasm than wisdom. In short, each case has to be taken on its own merits (killing intended organisms) and demerits (killing other things). Rather than depending on the idea that natural products are safe, you should assess each chemical by using the amazing amount of information readily available on reputable sources like Wikipedia and government-sponsored toxicity pages.

For the most part, commercially available pesticides (natural or not) are relatively safe because they have been tested for their effects on fish, birds, mammals, etc., though both natural and synthetic pesticides should always be used with care, especially aerosols if they are sprayed. Pesticides allowed for home use are typically safer (it is easy to tell when they are not - if the smallest amount you can buy is huge and costs a bundle, it is NOT licensed for the home). Some are safer than others - again, look it up. You can make your own choice about what you consider acceptable risk for you, your pets, honeybees, fish, or whatever else you care about, but don't fall into the "natural is safe" trap.

Orchidarium 4

The ongoing saga of adapting a commercial Wardian case as an intermediate orchid growing case, my orchidarium.

As you can tell from the photographs in previous posts I tried at first to use natural lighting for my Wardian case. This was not satisfactory because 1) it was very hard to adjust the amount of light, and 2) all the plants oriented leaves and growth toward the window and away from my view.

I am now installing a single LED lamp (Kessil Tuna Sun A160WE, designed for aquarium plants), which will be mounted above the cabinet and will shine through a pane of glass covering a hole I will cut in the steel top. I will probably want to use 2 of these lamps, but I will see how this one works first. The lamp is not cheap, but it has a good spectrum for plant growth but appears natural to the eye (unlike the purple lamps commonly used to grow "recreational" plants), an important consideration if you are going to view your plants rather than smoking them. It is also dimmable so that I can adjust the brightness according the plant response. The lamp has an excellent reputation among aquarists and it is quiet and produces little heat, and none inside the orchidarium (except from the light itself of course). Finally, because the light cone will come from a high point source, I can site plants nearer the center or to the sides (as well as high and low) to meet their specific needs.

As for the earlier vent fan installation, I will be cutting the steel Wardian case top with a Dremel steel cutting wheel and a keyhole hacksaw, which is unpleasant but fairly easy.

Much to my disappointment, lux measurement low in the case from the single A160WE lamp was much lower than I had hoped. I added an A360WE lamp, which together triples the amount of light, and I will be adding reflective material on the back and side walls. I will see how things go. All of my orchidarium plants were intentionally selected to like low light levels (no more than Phalaenopsis light), so I think this will work. Altogether this makes the lighting the most expensive part of the whole project. High intensity fluorescent is still much cheaper, but with the design of my case it would be difficult to mount them outside the case (the entire top is a sheet of steel) and heat would be an issue. The LED lights vent their waste heat outside the case.

Vanilla planifolia, Orchid of the Month, August 2017

The cured and dried seed capsule of the vanilla orchid, whole and chopped

Only a single orchid of the approximately 28,000 known species is widely grown for food - the famous vanilla orchid Vanilla planifolia. More about the food later, for now the plant. The Vanilla genus is one of the earliest diverging branches of the orchid family and their growth habit is unusual, though the flowers are immediately recognizable as orchids, with a lip and a column and all those goodies. Vanilla planifolia (hereafter Vanilla) is described as monopodial (stem and leaves from a single foot), but if you are envisioning a Phalaenopsis or even a Vanda, your image will be way off. Vanilla is a vine. With roots in the earth, the plant can extend tens of meters up a tree trunk to reach higher light in the tree crown. Still, if you shortened and straightened the stem, the plant would look roughly like a wide-leaved Vanda, albeit with a lot of leaves. Members of the Vanilla genus are found across the world in wet tropical climates and Vanilla planifolia is native to Mexico through northern South America, though now also grown commercially in other areas.

Vanilla grown as an ornamental - the trunk is a tree but the leaves are Vanilla

Vanilla (the flavoring) is the seed pod of Vanilla planifolia after curing, the well known dark brown "bean" of the photo at the top. If you google "vanilla" and look at images, they correctly show the beans with a flower, but to my amazement none of them are actually the Vanilla flower, despite the fact that it is quite lovely. On my browser in July 2017, the top hit images in order include a flower of: a Phalaenopsis, a Dendrobium, a flower that is not an orchid at all, another Phalaenopsis (this picture is from an article claiming that vanilla treats just about everything that ails you, including preventing cancer, so I suppose the mismatched flower is the least of its offenses), a Cymbidium, another Dendrobium, another Cymbidium, etc. It is not until the 16th bean/flower photo that there is one that looks like a Vanilla flower. As if this were not enough, a few of the top hit images also include leaves that are definitely not orchid leaves, though I can't say what kind they are. Incredibly, even googling "vanilla flower" gets a top hit that is clearly a Cymbidium flower, though the second and seventh top image hits appear to be Vanilla flowers, which is slightly heartening. As the French say, incroyable! Now these images are found in articles that focus on vanilla as a food (and a dubious medicine), but really: how hard is it to be at least vaguely accurate? It reminds of Hollywood movies and the 45th president of my own United States - truth as marketing or convenience.

An alba form of the actual Vanilla planifolia flower

Rant over, back to reality. The vanilla seed pod arises of course only after pollination of the flower and the flower is very short lasting, so to ensure efficient pod production in vanilla plantations, the plants are hand pollinated. After the pod largely ripens on the vine, the pod is cut and undergoes several steps of curing to develop the best aroma and flavor, largely comprised of the compound vanillin, with a few other compounds contributing to complexity. I am interested in scents and I have a vial of pure vanillin - I don't know about the taste, but I can assure you, you would be hard pressed to tell the scent of vanillin from vanilla bean. And here vanillin is in all its chemical glory, looking as if it might poison you or strip the flesh from your bones, but in fact quite benign and smelling like heaven:

All of the Vanilla species form very large plants, so unless you have a huge greenhouse, a strong desire, or an appropriate outdoor climate, you won't be growing them. But you have eaten them many times, and will many times again. Vive la vanilla!

Paphiopedilum rothschildianum, Orchid of the Month, July 2017

Paphiopedilum rothschildianum flower, which can be 20 to 30 cm across

Paphiopedilum rothschildianum is a commanding plant with an extraordinary flower and is much beloved of Paphiopedilum growers, but it also has other charms that make for a good story. The plant has long glossy strap-like leaves and a tall multi-flowered spike with one of the most distinctive flowers in the plant world. It is terrestrial and grows in Borneo (more about that later) on steep slopes on rocks or among plant detritus that isn't quite soil, usually above running water, often exposed to unusually sunny conditions for an orchid.

Paph. rothschildianum plants in situ in Borneo

If growing only in Borneo isn't enough to make it feel exotic to you, this plant has been found only on the lower slopes of a single mountain in Borneo, Mt. Kinabalu. Okay, it is a really big wide mountain, but still this is one rare plant in nature. There is presumably something special about this location, because this is not a plant struggling to make it by - it is locally abundant. When it has the right conditions it thrives. It could be the microclimate or the soil/rock type is just right, or it could be that its coevolved syrphid fly pollinator is found only in that area. Tropical climates generally support more biological diversity, in part because species are native to a smaller area, but this example is extreme. This gradient of biological diversity is called, cleverly enough, the latitudinal diversity gradient, and it well worth your time to read about - for one thing nobody is sure exactly why it happens.

Speaking of syrphid flies, also known as hoverflies, these are thought to be the pollinators of Paph. rothschildianum. These flies are familiar to those in temperate climate because many species look rather like a bee, with black and yellow stripes (hoverflies don't sting, and their coloration is a case of Batesian mimicry, but the full story takes us too far afield). The larvae of many syrphid flies eat other insects, and mother fly provides for her young by laying eggs among their preferred dinner. In the case of the fly that pollinates Paph. rothschildianum, dinner is aphids and the staminode of the flower has two parts: one part packed with bristles with a fat white tip that apparently looks like a bad aphid infestation to mother fly, and the other part waxy and presumably slippery to the fly. The fly lands to lay eggs (and often does lay eggs, thus dooming her aphid-eating larvae), slips and falls into the bucket-like lip below, and the rest of the process is the same as for all of the Lady Slipper orchids: the slippery walls, the escape route, the pollinia - described many times all over the web. Apparently the trick of luring unwary syrphid flies by mimicking aphids is shared by some other Paphiopedilum and Phragmipedium species, though I am not sure how many. The staminode bristles don't look quite like aphids to me, but then again I don't know what kind of aphid the fly is looking for, and there may be olfactory and tactile cues as well. As for why the rest of the flower is so large and boldly marked, I confess I have only a poor idea. To me it says "beware syrphid fly, here be fake aphids", but perhaps the fly can't figure this out, but is smart enough to learn that huge aphid colonies (appear to) infest these places. This should be an evolutionarily stable strategy if the frequency of real aphid infestations is much higher than Paph. rothschildianum flowers.

Close up of the staminode (the V-shaped structure near the middle), with the white-tipped aphid mimic bristles covering all but the outer (leftward) face, photo from IOSPE.

And finally, another picture showing the strap leaves and the bold flowers as they might appear to a female syrphid fly looking for a great place to lay eggs. Oh yeah, and they look pretty awesome to us humans too.

Peloric Flowers and Orchid Evolution

If you browse for novel orchid flower types for sale or for fun, you will occasionally run across "peloric" flowers. Peloric in botany means abnormally regular or symmetrical, and that's what these flowers tend toward. To explain how and why, I need to talk about orchid evolution and the genetics of flower parts. Though the genetics of orchid flower parts has not been studied in detail, we can make reasonable inferences from studies of other flowers that have been studied.

Orchids originated from a group with flowers with 3 identical sepals and 3 identical petals. The sepals and petals were 3-fold symmetric and each formed a "whorl" in the developing flower bud, the sepals forming the outer whorl and the petals the inner whorl. (Some plants have additional symmetric inner whorls that form the stamens and styles, which contain the pollen and female receptive organs respectively. In orchids these parts are transformed almost beyond recognition and form the single column.)  One of several evolutionary innovations in the orchids was the breaking of the 3-fold petal symmetry, such that one of the petals became the labellum (lip) of the flower. In many orchids, the 3 sepals remain nearly identical, though this symmetry is also broken in some specific groups. Typically, in currently extant orchids the lip is dramatically changed in shape and color, but usually the lip plus the two petals retain 3-fold positional symmetry.

Phalaenopsis Fantasy Musick, comparing normal flower form (left) with strong petal to lip peloric form (right)

Peloric flowers most often arise when the two petals acquire some or all of the character of the labellum, resulting in a flower that is more symmetric than normal. In extreme cases, the two petals look nearly identical to the lip, giving rise to a true 3-fold radially symmetric flower with respect to both petals and sepals (photo above). More often, the two petals acquire bumps, deformations, or colors that suggest some characters of the labellum, but the transformation is incomplete. Sometimes the "peloric" changes are so slight that it is seems to me to be a guess that they have become lip-like and the flowers certainly are not radially symmetric. In rare cases, the peloric transformation is the reverse - the lip becomes more like the petals (photo below). These are peloric in exactly the sense as the more common type - the flower approaches 3-fold radial symmetry - though the transformation is reversed and the visual effect is very different. All of these changes are probably due to mutations in the genome because they are stable in a given plant, though the best test is to make crosses and flower the progeny and I am not aware of any such data.

Dendrobium Kuranda Classic x Classic Gem individual showing strong lip to petal peloric form

Often flowers in which the petals look odd in any way are called "peloric", but this isn't strictly correct unless some element of additional floral symmetry results. The genetic basis of such changes might be partial petal to lip transformations, or they could simply be changes in genes that control petal form (and have nothing to do with the lip). Nevertheless, a lot of these odd petals do look reminiscent of the lip on the same plant and I think extending the meaning of peloric to these is sensible. Examples of all types are easily observed by a web search for "peloric orchid". 

What does this tell us about orchid flower development? Now I am only guessing, but I think these are educated guesses. First, the genes that determine lip shape have been added on top of an originally three-fold symmetric petal whorl. Second, since the most common peloric type causes petals to look more like lips, the lip-shape genetic program has the potential to be expressed at an early stage in petal development, but it is normally shut off in petals. Mutations that partially or fully prevent this shut off give rise to the common peloric type. Third, it is possible, though rarer, to acquire mutations in the genetic program that specifies the labellum shape, so that the lip becomes more petal like. Why these are rarer I don't know, but it suggests that the number of possible mutations of the latter type is smaller than the former (in genetics jargon, the "target size" is smaller).

I don't find peloric flowers to be particularly attractive, but they are interesting and someday perhaps we will understand in detail which genes are affected and how. The genes involved in controlling flower parts are well understood in model plants such as Arabidopsis thaliana, and the same sorts of genes are probably responsible for flower parts in orchids. Orchids are a poor model system for geneticists because they grow so slowly, but they have one huge advantage - thousands of people all over the world are growing millions of orchids and keeping an eye out for strange flower forms. These might form the basis of effective inference about the nature of these genetic changes at some time in the future, probably through a lot of genome sequencing combined with a few genetic crosses.

Windowsill Orchid Growing Part 1

Orchid magazines and orchid shows in temperate climates are dominated by greenhouse growers. Growing orchids in your home has some obvious disadvantages - relatively hard to control humidity, light, and temperature most obvious among them. You should not try to grow difficult species in the home, unless you invest in or build an orchidarium, which amounts to a miniature indoor greenhouse. However, if you choose plants that don't need crazy humidity and with the appropriate temperature and light needs for your particular windowsill, you have already leveled the field a great deal. Add a humidifier and you are about level. Add personal attention to each plant as an individual and you may have the advantage. Take that rich dead Victorian white guys!

The smaller scale of windowsill growing provides some distinct advantages over any but the most meticulous greenhouser. Many of the pests associated with greenhouses are absent or easy to control at the windowsill, including slugs, snails, and fungus gnats. Furthermore, the attention given to each plant as an individual is very difficult to achieve in greenhouse growing, where the emphasis tips toward scale. As one of many examples,  a lot of the watering in a greenhouse is done by automated misters and drippers or at best by walking around with a hose wand. At the windowsill you know every plant or you stick your finger in the medium and water when needed, and your watering (with a little knowledge and skill) is always near perfect.

I have grown at the windowsill for many years and here I will share some of the knowledge I have gained that isn't always clear when reading literature written by and for greenhouse growers ("position the plant near the wet wall and use 70% shade cloth" ... gee thanks, great advice!). There are other windowsill methods out there that I am sure can work just as well - I am just telling you what I do and why. 

Water quality. First, get a total dissolved solids (TDS) meter. They are cheap and if you grow sensitive plants and follow my plan, you get one for 'free' (it comes with the deionizing system). Unless you grow sensitive orchid types, mostly Pleurothallids such as the genus Masdevallia, if your tap water has less than 100 TDS you should be fine using tap water for everything. I am fortunate that my tap water has about 30 TDS and I use it for the large majority of my watering. Ignore occasionally stated fears about chlorination - it might be a minor issue but trust me, you can grow fabulous orchids with chlorinated water. If you do grow sensitive plants or your water has very high TDS, just get a ZeroWater pitcher or the equivalent. This is a simple and *very* effective system for removing impurities in water, consisting of activated charcoal and an ion exchange resin. The charcoal will get rid of most organic molecules and chlorine, but the ion exchange resin is much more important for your orchids because it gets rid of the salts. My water goes from 30 TDS to 0 TDS with one pass through the ZeroWater cartridge (and the pitcher comes with a perfectly good TDS meter - I was cynical and got another meter and it gives identical values), and it is extremely easy to use. The flow rate through a ZeroWater is not very high, so I just make collecting the modest amount I need an occasional chore as I pass through my kitchen - pitcher full? decant into plastic jug, top off pitcher, time 20 seconds. I change the cartridge when the outflow goes above a few TDS. Buy the cartridges in bulk direct from ZeroWater (or equivalent) and the cost is very modest - for me it is perhaps $3 per month. Cost could become an issue if you use a lot of water and you have very salty tap water because that will exhaust the ion exchange resin faster. In this case you can purchase a reverse osmosis system or collect rainwater, but I don't recommend that unless you need a lot of water - they are a pain in the neck and have their own costs. There are also simple deionizing columns available from marine aquarium vendors; these may be more cost effective than ZeroWater. Another advantage of having deionized water is that you can water your small plants by spraying the medium at the windowsill, which is easier and works especially well for plants in all spaghnum, such as Neofinetia falcata potted in the traditional Japanese fashion. Still flush at the sink once in a while, as discussed below. [A side note on TDS: the usual method used to measure TDS is imperfect - you are really measuring the electrical conductivity of water, which is dominated by dissolved ions like sodium, potassium, chloride, and magnesium. If you dump pure sugar into your water you will find that it barely registers on a TDS meter even though sugar is definitely a dissolved solid. Fortunately the dissolved solids in ground water are dominated by dissolved ions and all the ions have about the same effect on conductivity, so the TDS meter is effective.]

Watering. Here you have the advantage over greenhouse growers, at least if you are reasonably conscientious. Every plant gets individually watered when it needs to be. Simple. Well, mostly simple. If you are like me when I started growing orchids you wonder: what does it mean to water "just when the medium gets dry"? Dry on top? Dry in the middle? Bone dry? Or how about "keep evenly moist". Huh? Honestly, I don't think anyone knows quite what they mean when they make such statements, but they do give you a relative guide - obviously the latter is wetter than the former. My method (profoundly original) is to stick my finger down an inch or two into the medium. In good open orchid medium it will never feel sopping wet (if it does, repot), but if it feels damp you are fine for another day. Of course you have to adjust this depending on how wet the plant likes to be, and perhaps seasonally. Until you get the hang of it, be very consistent about checking each pot each day - it is amazing how much plants will vary from each other and from season to season. Media vary in how much water they hold, pot size matters (surface to volume ratio), temperature and humidity have a big effect, and less obviously, if you have a plant with a lot of leaf area and a pot packed with roots, it is amazing how much water the plant itself will suck out and transpire - in warm weather, daily watering may not be enough (see repotting in a future blog post to see how to deal with this). So just ignore all these variables and use the finger test every day for a while. Eventually you will get the feel for when you need to check a plant.

My watering method is simplicity itself and is reasonably fast: I carry the plants to my kitchen sink and run a heavy stream of tap water directed at the medium (not the plant) of each until it runs FREELY out of the bottom and then a couple seconds more ("flush" the medium every time you water). I let them sit a few minutes so I don't drip all over my wood floors and carry them back. Some plants might appreciate a light misting on their leaves as well, but if you do this use deionized water, otherwise you will build up those ugly white stains on the leaves. Even with a sizable collection on a typical day there is less than one sink full of plants; quite efficient. If you grow other houseplants and are new to orchids, notice that this is nothing like the watering you are used to. Let it flow, let it flow! Pretend you are mother nature dumping a tropical rain onto an epiphyte: the roots are soaked in the first minute and then the rest just runs off. Orchids hate salt on their roots, and if you don't flush your pots when you water, it will build up by evaporation. You will quickly see how to adapt this method a bit to various media, such as small pots or pure spaghnum or very fine bark (lower the flow rate but still flush). You can't overdo the flushing. More won't hurt; this is not over watering - that means watering too often so the roots don't get enough air - this is making sure the medium is evenly wet and salts don't accumulate. The medium won't be any wetter when you finish, but it will be clean clean clean. When medium such as fir bark is brand new you can let the pot soak in a bucket for a few minutes, because new bark doesn't soak up water very well, but I doubt it matters much and this method is much more time consuming and it risks transmitting disease unless you do one at a time and clean the bucket every time. I just soak new bark repots once and then water a bit more often for a month or two.

For mounted plants, which are not common at the windowsill because they are a pain, just use the same method. You can also water by misting mounted plants (or smaller pots), but if you do this be sure to use deionized water or flush the plant at the sink often!! Salt can build up on mounted plants very fast when you are reluctant to let your sprayed mounts drip all over your carpet or wood floors.

Water this way conscientiously and you have solved 90% of the problems people have growing orchids at the window sill. Well okay, 80%.

Fertilizing. This part is easy. First, follow the mantra "fertilize weakly weekly" (or less), weakly meaning at no more than half the label-recommended strength. Second, when you fertilize, water first as described above and then pour on some fertilizer water until it just starts flowing out the bottom (I am not sure the issue is real when dealing with dilute liquid fertilizer, but this is supposed to avoid "fertilizer burn"). Third, purchase an epiphyte-specific fertilizer with all the micronutrients (calcium, magnesium, boron, cobalt, copper, iron, manganese, molybdenum, and zinc, in addition to the big three, nitrogen, phosphorous, and potassium). Plants also need sodium, chlorine (chloride), and sulfur, but those come as the counterions for the other nutrients, and for some reason aren't listed as nutrients in fertilizer I use. (They also need lots of carbon and oxygen but those they get from the air.) If you use only tap water with moderate TDS, you don't have to bother with all the micronutrients because they are already in your water. 

If you poke around enough you will find people who never use any fertilizer, but that is not a good idea. Apparently they manage, but the nutrients have to come from somewhere, probably the potting media and tap water. Plants are amazing, but they are not alchemists. If you own parrots you could try leaving them loose in your home - that might work but it would get a bit messy unless you can train them. It would be very natural.

That's it. Ignore all the rest of the hoopla. I use Dyna-Gro Orchid-Pro, but I don't specifically endorse it - there are several other brands out there that are equivalent. Just read the fine print on the label and ignore the rest. I am not sure why there is so much hoopla out there about fertilizers, most from the companies of course, but a surprising amount from growers. There are studies on urea as a source of nitrogen (under normal conditions it is fine, because bacterial rapidly convert it to plant-usable nitrogen), but as far as I can tell all the rest of the endless discussion is marketing, placebo effect, or minutiae. 

Foliar fertilizing, blossom booster, vitamins, hormones, magic additives, annoying names, it is all bunk. Gack! Boycott more hype! My favorite bunk - the SUPERthrive label is like a caricature of snake oil sales pitches. And the fine print is even weirder: 

“SUPERthrive saves plants from waiting to make many life-process complexes, carbon-hydrogen-oxygen groups. Bankruptcy protection. Turgidity maintenance. Displaced groves salvage. Marginal methods, times, places and plants. For immediate use by your plants.”

Sounds mentally ill to me, or at best very confused. Go ahead, be one of those suckers born every minute. But first watch the YouTube video on a reasonably controlled experimental test by BrightGreenThumb (conclusion - it has no discernible effect, though the experiment is on common garden plants not orchids). 

My favorite empty hype - pure snake oil. The label is an impressive mishmash of hot button words. There is no evidence I am aware of that the product does anything useful. It does contain low concentrations of auxin (a plant hormone) and B-vitamins, which plants make for themselves. And it also contains "over 50 secret proprietary ingredients that we do not disclose", always a comforting claim. In case you missed the point, these ingredients are private, confidential, under wraps, classified, and concealed (as well as secret, proprietary, and not disclosed). So who knows, maybe it will "super extra life champion miracle hormone science vitamin millions revive world proof thrive" your plants! 

More to follow in Part 2, complete with occasional rants...

Zygopetalum Jumpin Jack

These are flowers from my plant of Zygopetalum Jumpin Jack, a hybrid registered by R. Murray in 1996. Like Zygopetalum species, this hybrid has jungly brown and green sepals and petals and a purple and white lip; this hybrid was probably chosen in part for its darker brown and purple colors. If you look closely, you will notice that it sometimes gets confused about which way is down (flowers in the background). Photos of two of the species likely to be part of the genetic background are posted at the bottom. 

This is a fairly large plant - mine currently has 8 cm egg-shaped pseudobulbs each with several long slightly plicate medium green leaves up to 45 cm long and 4 cm wide. Each flower is about 8 cm wide and they last about 5 weeks for me. The plant is vigorous and handsome even when not in flower and it flowers readily. Most Zygopetalum species are native to low and mid-elevation rainforest in Brazil, growing as terrestrials, lithophytes, and epiphytes, and their hybrids are popular houseplants, presumably because they are easy to grow and have spectacular flowers. Many also have a strong scent, variably described as similar to freesia or hyacinth. Mine has a rather weak scent, but it is also very distinctive - it smells to me just like freshly baked acorn squash with perhaps a touch of allspice. Weird. My daughter Zoé named him (and her) Jungle Jim, so that is our (unregistered) hybrid clone name: Zygopetallum Jumpin Jack 'Jungle Jim'. Jeepers!

I grow mine on the windowsill in bark mix in a plastic pot, with medium bright light, fairly wet, intermediate temperature, and no special care. Zygopetalum species and hybrids are reported generally as quite tolerant of growing conditions. If you are an orchid novice, I can heartily recommend them as starter plants - though I would suggest getting one that you have smelled in bloom as their scent varies a lot. I have smelled some that are strong enough to fill a large room and others with no scent at all.

My plant was acquired from Seattle Orchid and is an unnamed clone of this complex hybrid, with both parents also registered as hybrids. Many Zygopetalum species are quite similar in appearance and I did not try to track the parentage of this one all the way back to species. Here are two of the species that are likely part of the parentage:

Zygopetalum maxillare

Zygopetalum mackaii

Orchid Genome Sequences

In 2015 the first complete orchid genome sequence was published (doi:10.1038/ng.3149) and several others are on the way. The genome was for Phalaenopsis equestris but the main findings probably apply to most or all orchids. I won't talk about the results of this paper, which frankly, like most genome sequence papers these days, are a bit dull (although that is my professional area of work so they seem routine to me and would probably be highly technical and unreadable to you). What I will talk about instead is the astounding and ongoing drop in the cost of sequencing DNA and what it will mean for the future of ... drum roll please ... orchids. Not people! Who cares about people! Plus the promise of "personalized medicine" (roughly meaning medicine that takes into account your very own unique genome sequence) has been extensively written about and wildly over hyped in mainstream media. Here's what you can actually expect from personalized medicine: not much, or at least not for a very long time. Incremental improvements in a few cancer treatments and in judging appropriate drug dosages. That's it. Not even close to vaccines or antibiotics or good old segregation of sewage from drinking water.

Okay, now that I have offended most of the biomedical community, big pharma, little pharma, and half my readership, let's get down to things that matter: orchids. To do that I need to talk a bit about sequencing costs. Since DNA sequencing went large scale in the mid 1990s, the cost of determining the sequence of a segment of DNA has dropped by 4 or 5 orders of magnitude (factors of 10). This is a much faster gain than the famous Moore's Law for semiconductors on a chip. And the cost drop for now (2017) is continuing at about the same pace. It is likely that the cost of sequencing your (human) genome will be on the order of the cost of a postage stamp in a few years. (This is only the cost of running and amortizing the sequencing machine itself - at some point sample preparation, analysis of the output, and other ancillary activities will become more expensive than the sequencing itself.) Orchid genomes are substantially smaller than human genomes, so their cost will be proportionally smaller as well.

What does this mean for the hobby orchid grower? Well, mostly two things that I can think of at the moment. 1) All of that squabbling about taxonomic classification will be laid to rest (well, almost all of it). 2) No more need for misidentified plants, elaborate hybrid naming systems (and errors), and all of the aggravations that come with them. When you purchase a Dendrobium guerreroi 'CC9607' there will be no excuse for it being anything else. The frequency of these errors is high from what I can tell by reading responsible blogs from serious orchid growers. And the name Dendrobium guerreroi will stay Dendrobium guerreroi permanently. In theory, we can get rid of all these imprecise names altogether: you will simply say I have a "GCCTAGAATCGATC... [1 billion more letters]". Hmm, maybe that won't work.

If you are an orchid hybridizer, cheap DNA sequence could mean a lot more - being able to follow all the traits you care about through crosses without have to wait 10 years for a plant to mature. This won't be easy in the near term, but eventually the technology will assist in all kinds of directed breeding efforts, including make a hybrid Cattleya that is compact, grows fast, makes myriads of brilliantly colored flowers, tastes delicious, and whatever else you can track.

Though the cost of sequencing a genome will be very small, the machines and computers needed to get the sequence are still quite large and specialized, so for the time being you will generate sequence by sending samples to a center. A sample can be as small as snippet of leaf or root. There are handheld DNA sequencing machines available and/or on the near horizon but they are much more expensive per DNA sequence than the cheapest center-based technology. Nevertheless, we can probably expect a DNA sequencer in every, oh ... let's say library or corner store or something of that sort, in the near future. (Notice how I have cleverly used the vague term "near future" so that I can claim to be correct no matter what happens.) When will this all appear on your cell phone? Who knows, maybe never because it is too specialized, although it is possible I am not being imaginative enough. Not many people walk around thinking "I wonder whether the genome sequence of that dandelion is special in some way?". I do, but you probably don't. Unless you are odd and have a hobby like growing orchids.

Orchid Stomata, or how and why a plant can hold its breath all day

Q. What do orchids have in common with cacti and other arid climate plants? 
A. Their stomata and a special pattern of photosynthesis. (Well yes, they also are both grown by eccentric people, but that is the wrong answer and I am grading this exam.)

Most plants open their breathing pores (stomata, singular stoma) in the day and close them at night, but cacti and most orchids and a few other groups of plants open them at night and close them during the day. This night-open pattern is coupled with a biochemical pathway that allows these plants to use carbon dioxide in a special way. Most plants open their stomata during the day to enhance delivery of carbon dioxide to the photosynthetic chloroplasts. The "fixation" of carbon dioxide from the air using light is one of the defining adaptations of plants - the carbon in their stems, roots, leaves, and flowers all comes from carbon dioxide in the air. Our carbon does too, indirectly via plants. Okay, that makes sense - plants can only perform photosynthesis when there is light, so they open stomata to let carbon dioxide into the leaf when there is light and they close them up to conserve water at night, when they can't use the carbon dioxide anyway.

So how can orchids and cacti fix carbon dioxide? They hold their breath all day! Or more precisely, they only open their stomata when it is dark! First clearly demonstrated by Aubert in 1892 with many details worked out later by others, the key is that these plants open their stomata at night and store the carbon dioxide as the small molecule malate, then convert it back to carbon dioxide during the day. (Malate, by the way, is tart tasting and is abundant in many fruits including apples - genus Malus, from Latin for apple. The compound is named for apples.) Photosynthesis then uses the released carbon dioxide in the same way as nearly all plants do (via a cycle called C3 photosynthesis). The nighttime storage consumes energy, but the daytime photosynthesis captures more energy (from light) so the energetic balance is positive. For reasons that are more confusing than enlightening, this is called crassulacean acid metabolism or CAM. Short version: orchids take a great big breath at night and hold their breath all day.

Cacti and many other dry adapted plants use CAM because it allows them to keep their stomata closed during the hot daytime. This conserves water, which is inadvertently lost through the open stomata, much as we lose large amounts of water breathing. Cool night air lets them acquire carbon dioxide but lose little water.

Water vapor condensing from exhaled breath.

And why do orchids do the same, including ones that grow in wet cloud forests? Well, it is probably for the same reason - to conserve water. You should be crying foul about now: but my Masdevallia plant grows naturally in 90% humidity with daily rainfall! Despite this, epiphytes are often water challenged (though not as much as cacti) because they lack the large underground root systems that provide abundant water to most plants. Indeed, not only orchids but most other epiphytes, such as Bromeliads, use CAM. This water challenge also contributes to the fact that so many orchids have waxy thickened leaves or pseudobulbs. You may have noticed that a lot of orchids look like succulents, despite growing in wet areas.

And there you have it - cacti and orchids, sisters under the skin. And a blog post about orchids with human breath as the only picture. I am very proud of that.

Corallorhiza maculata - Orchid of the Month, June 2017

Corallorhiza maculata, Walter Siegmund, GNU licensed at Wikipedia

Corallorhiza maculata (Spotted Coralroot) is a very unusual orchid that grows on the ground in mountain woodlands throughout North America. In my native Pacific Northwest, it is locally abundant - the visible parts of the plants are erect coppery pannicles of small flowers. Close up, the flowers are brightly colored and showy but they are small and when hiking you notice at first the flower spike as a whole. The plant flowers in the spring but when the spikes dry up they stand like dead sentinels for months, so it is easy to see where coralroots grow even when not in flower, despite the fact that the rest of the plant is under ground. The genus Corallorhiza gets its name from the roots, which form dense clusters of stumpy projections, looking more like certain marine corals than our usual idea of roots.

Corallorhiza maculata, by Ron at nativeorchidsofthepacificnorthwest.blogspot

Dried flower spikes, Gerry Carr, Florida Flora Image Project

The flowers are lovely but what makes this orchid unusual is that it is mycoheterotrophic - it parasitizes fungi. Under the ground. Secretly. All over the forest. It is a conspiracy theorist's dream plant. It has no leaves, no chlorophyll, not even a hint of green anywhere. Except for the flower spikes it is invisible. Where I grew up in the Northeast U.S. a more common mycoheterotroph is the Indian Pipe (Monotropa uniflora, not an orchid), but in the Northwest coralroots are much more common.

As you may know, forest soil is packed with fungal mycelia (not the mushroom fruiting body, but the wispy white threads that form most of the fungus). Those fungi are mostly either saprophytic (living on decaying plant material) or mycorhizal (living as a mutualist with live plant roots). Corallorhiza maculata is reported to parasitize Russulaceae fungi, which themselves are mycorhizal with trees and shrubs (and produce Russula mushroom fruiting bodies above ground). The orchid somehow extracts a living from Russula mycelia as a parasite (not a mutualist).

Here is a fungus, which we usually think of as degrading things, being used as food by a plant, which we usually think of as the ultimate biological producers. And an orchid no less!