Friday, August 30, 2013
Species name: Rosmarinus officinalis
Common name: rosemary
Location: teaching lab at Western
Rosemary is an incredibly unusual plant in the mint family (the Lamiaceae) because of its almost cactus-like lifestyle. The Latin name of this plant actually comes from its unusual ability to acquire nutrients in a hostile environment: "ros" for dew, and "marinus" for ocean. Not only is this plant incredibly salt-tolerant (with much of its native range in marine spray habitat), but it can acquire almost all nutrients it needs to sustain life from the air, where droplets of dew condense on the hairs and waxy coating of the leaves, where they are absorbed and used by the plant to make energy. In fact, rosemary is so drought-tolerant it can go without being watered for months. This makes me seriously wonder how I managed to kill my rosemary plant in a single month; something tells me I over-watered and should only have been misting it. It was one of those strange rosemary Christmas trees, so it might have also been root-bound. Yep, let's blame it on being root-bound. Then it's not my fault. :) Rosemary is native to the Mediterranean, where it still commonly grows in the wild. It is also a popular ornamental species, and some rosemary plants are hundreds of years old.
Rosemary is one of the most popular herbs to use in cooking, especially in meat dishes because it has such a distinctive flavour. In fact, what most people don't know about rosemary is that the flavour is best brought out of the herb when you "spank" it (for a refresher on why you might want to spank an herb, refer to my blog post about mint HERE) and then burn it. Yep, that's right. Burn it. One of the best ways to use rosemary is on barbecued meats where you poke some sprigs of rosemary into the meat and just let them singe and burn until the meat is cooked to desired done-ness. Take the burnt pieces out of the meat with some tongs before serving (or just eat it. Burnt rosemary won't kill you), and voila! Smoky rosemary-infused meat. Yum, yum. Rosemary also pairs really well with mustards, because the acidity in the mustard also brings out the flavour in the rosemary leaves. Interestingly enough, mustard is native to almost the same geographic region that rosemary occupies. There might be something to this mustard-rosemary pairing...
As the Latin name suggests, rosemary has been used for centuries (some people have argued for many millennia, but the evidence for rosemary use only dates back to about 3,000 years ago. Yeah, "only.") as a medicinal plant, mainly to improve memory. It wasn't just used to improve "brain memory," either, but also to improve muscle memory. After someone suffered a stroke in the Middle Ages, a salve of rosemary leaves ground into wine was applied to the site of muscle paralysis as it was believed that doing so would help the body "remember" how to move the paralyzed muscles. It probably didn't work very often, but at least you would smell good :) That type of concoction was also consumed orally to treat gout (it was most famously used in this manner to treat the Queen of Hungary Elisabeth of Poland in the 1300s). Don Quixote also used rosemary leaves in his miraculous balm of Fierabras, which was reported to heal anyone that drank it. This very likely had at least SOME effect on the body, as the secondary compounds of rosemary are highly antimicrobial. Back in the 1100s and 1200s, before the discovery of penicillin, any kind of wound that got an infection would almost certainly lead to death. By either drinking this highly antibacterial (and antifungal) beverage or applying it directly to the wound, it would help protect it from infection. For some wounds it would have been irrelevant as they would be severe enough to kill you anyway. But for other more minor wounds, it might have made the difference between life and death. It's always nice to know when some of the folklore of popular tales is actually biologically possible!
Because of its historical medicinal use in improving memory, rosemary sprigs also play a leading role in wedding and funeral traditions around the world. In funeral bouquets that are scattered on graves, rosemary serves as a sign of remembrance for the dead and a way of honouring their memory. Across much of Europe, rosemary is still incorporated into the wreathes in Remembrance Day ceremonies, and also in war commendation ceremonies (especially if these are to commemorate the brave acts of a soldier who died in battle). In wedding ceremonies, they represent remembrance of loved ones that passed before the time of the ceremony and also to remember the life the couple spent apart before they were united in marriage. This eventually caused the evolution of rosemary from an herb of remembrance into an herb of love, and now sprigs of rosemary are considered to mean love and good luck in marriage. The sprigs of rosemary in the bride's bouquet would be planted in the ground, and if they grew it would be a sign of good prosperity and good luck. If they didn't grow...well, I guess it sucks to be you. Hint: dip it in some rooting compound first and problem solved. See, there's always a way to coerce luck into working out in your favour. Just takes some work!
Monday, August 26, 2013
For this blog, like the blog post I wrote about different species of geraniums (which you can read about HERE), I'm going to profile 4 different species (well, two species and two hybrids; sometimes only one species, two hybrids and one variety depending on who you ask) of mint. These plants are all in the genus Mentha, which is the "true" mint genus (there are other groups that are called mints but that are not in the genus Mentha; these would be close relatives of this genus that would be in the mint family, the Lamiaceae). The four types of mint I'm going to profile are: orangemint, menthol mint (or peppermint), spearmint, and mojito mint. The photo below is a photo of all four of these plants on display in the teaching lab:
You'll notice that I conveniently numbered all of the pots in the order I'm gong to profile the plants :) I love it when I plan ahead. So let's begin!
Species name: Mentha citrata (sometimes Mentha arvensis var. citrata)
Common name: orangemint
Location: teaching lab at Western
Orangemint is sometimes only known as a variety of water mint (Mentha arvensis), but I like to consider it a separate species. Currently, whether it's a species or a variety is still up for debate since DNA studies can't quite rule out either option. Mints are notorious for being able to cross-pollinate each other regardless of what species they are, so there is a lot of genetic contamination of most "wild" populations, and greenhouse populations (unless bred to be sterile) are no better. Due to the huge difference in texture and shape of the leaves, I like to think it's a separate species. It's likely native to the Mediterranean (although this is debatable since it has been cultivated for so long in so many other locations it's hard to tell), and is potentially invasive in some areas (but not southwestern Ontario where I am).
So what is different about the texture and shape of orangemint leaves? Well, for one they're rounded. The reason why "spearmint" is called SPEARmint is because of the shape of the leaves: almost all leaves in the genus Mentha are very pointed at the end and have sharp teeth along the edges of the leaves. Right away this plant is definitely an oddity in the genus. The leaves are also much fleshier than other species of mint, and have a bit of a water storing capacity even if they aren't true succulent plants. This characteristic makes orangemint pleasant to eat...to a point. It has a much more satisfying chew to it than other species of mint, the leaves aren't as hairy and so don't give you as much of a "hairy tongue" feeling when you're eating it, but BOY does this plant ever pack a punch. Unfortunately, despite the leaves smelling like an orange grove in Florida or California, they don't taste a bit like what they smell. In fact, after chewing the leaves for a few seconds it's downright unpleasant.
Like most members of the mint genus, this plant has a dirty little secret. It has been used for centuries in a tea-like preparation as a medicinal beverage, and has been used to help everything from stomach aches and nausea to preventing or treating seizures. The pure extracted essential oils do show a lot of great medicinal potential for a variety of medical ailments (although not sold commercially for any disease, disorder, or symptom), but it's secret is that it is a potent carcinogen and mutagen. In fact, consumption of too much orangemint tea when pregnant will almost certainly lead to miscarriage. If it doesn't, there is a strong possibility for severe developmental deformities in the fetus (or embryo, depending on time of consumption during pregnancy). Because the compounds in orangemint extract are mutagenic, they cause DNA mutations which are irreversible. Always use extreme caution before consuming any "herbal" remedy during pregnancy. Just because it's "natural" doesn't mean it's safe!
Species name: Metha x piperita
Common name: menthol mint, peppermint
Location: teaching lab at Western
Next up we have the plant most commonly used to create the plant extract known as "menthol," peppermint. There are actually numerous species of Mentha that are used for this purpose, but the specific cultivar referred to as "menthol mint" is used most commonly because it has been bred to contain very high concentrations of this chemical. Peppermint is most probably native to Europe (there's the same problem as with orangemint for determining where exactly this species is native to based on the incredible amount of cultivation of this hybrid around the world), and is incredibly invasive in almost all areas it's planted.
One of the great things to note about many species of mint is that they are sterile hybrids. This means that the plant produces flowers, but these flowers don't have the ability to produce seeds. This is a great characteristic, especially in a potentially invasive species, because it means that the chance of this plant getting out of control can potentially be avoided. Unfortunately, there are two problems with this idea when it comes to peppermint: one, this hybrid isn't sterile (oops); and two, this plant produces below-ground biomass almost as quickly as it produces above-ground biomass. Peppermint plants produce huge numbers of rhizomes, which can grow underground and seek out new pockets of nutrient-rich soil to send up shoots to grow. This can cause the exponential growth seen in some areas, where for every one stem you pull out of the ground it seems like the plant sends up two more. Definitely a never-ending battle, and that mixed with the fact that it produces seeds that can blow away in the wind to create new plant colonies, means this plant is a very successful invasive species. Because of the fact that almost all species of Mentha have the potential to become invasive, you should never, EVER plant this directly in the ground, and especially not if you live near an environmentally significant or environmentally sensitive area.
Aside from the essential oil extraction, this plant is used for a remarkable number of uses. First, it is the most popular culinary additive in the world, especially in confections. In fact, there's recent evidence that its use goes back to 10,000 years ago in southeast Europe where it was found with other archaeological artifacts that suggest it was used to flavour food. It has also been used for medicinal purposes, as it is one of the most effective treatments for any kind of digestive issue from upset stomach to irritable bowel syndrome (IBS; there was a recent clinical trial that showed that the consumption of some amount, don't remember how much, of purified peppermint oil completely eliminated symptoms of IBS in 75% of women tested, and decreased IBS symptoms by at least 50% in all 15,000 women tested! That's incredible!). Now you know why restaurants give you an after-dinner mint! It decreases the feeling of being bloated, by encouraging the formation of small gas bubbles in your intestines. Might make you a bit gassy after a large meal, but I think that's better than laying on the couch groaning for an hour or two! Purified peppermint oil has also been used as a natural insecticide, as even in small quantities it prevents insect herbivory on most plants when applied as a spray. Purified menthol has been used as a medicinal additive for decades, most notably in muscle creams to give that minty smell but also a cooling sensation (which is why muscle rubs with a high concentration of menthol work incredibly well as methods of decreasing the itch associated with mosquito bites! The cooling sensation takes away the itch). Another good thing about peppermint oil is that it is one of the only members in the genus that does not display carcinogenic or mutagenic qualities, even in higher concentrations than one would ever be exposed to. In fact, peppermint tea is one of the most widely recommended "herbal remedies" for mild cases morning sickness.
Species name: Mentha spicata
Common name: spearmint
Location: teaching lab at Western
Spearmint is another incredibly commonly grown member of the mint genus, and like peppermint is incredibly invasive. It is not a hybrid so does produce viable seeds, but it also produces those same vigorous underground rhizomes like peppermint. Not a good combination! This species is native to Europe and southwest Asia, but is now grown commercially around the world. A very versatile plant, but one that should be treated very carefully; the flowers should be pinched off the plant before they're given time to set seed to prevent the spread of this species, and it should never, ever be planted directly in the ground.
Often with mint species (and other species used as herbs in the Lamiaceae like basil, rosemary, sage, and thyme), it is suggested that the flowers be pinched off before they're given much of a chance to develop. This actually has very little to do with the reproductive cycle of these species but rather with their use to humans. All plants display a phenomenon referred to the "allocation of resources" during all points of the plant life cycle, but this is more pronounced during flowering and fruiting. You'll notice perhaps with a lot of fruit trees that once the fruit starts to develop on the tree the leaves will turn and fall off at even the slightest change in climate without damage to the fruit. This actually has nothing to do with the health of the tree and everything to do with the attempt to give your offspring a healthy chance at being able to disperse and reproduce. Because (for example) a peach takes so much energy to produce a big, fleshy fruit around the seed, if the plant is under any kind of stress it will try to reduce the stress without impacting the next generation. This is why sometimes (especially nearing the end of the season) the leaves on the plant suffer. The same thing happens with highly fragrant plants once they start to produce seed. The seed producing takes much of the plant's resource allocation away from the production of secondary compounds (what gives the plant the smell), and instead puts all that energy into seed production. Great if you're a seed and want a good chance at being able to grow, but bad for you as a gardener if you want basil (or spearmint) with flavour! For this reason, make sure the flowers are pinched off the plant as soon as you see them start to develop. This will confuse the plant, and it will forget it was ever attempting to reproduce, ensuring that your leaves retain their potent flavour.
Like with peppermint (a hybrid created from spearmint), the essential oil of this plant shows very little mutagenic activity when tested. It is also effective medicinally against stomach ache, but so far hasn't shown much promise in the treatment of chronic digestive tract diseases or disorders. This is probably due to the fat that spearmint essential oil contains very little menthol and menthol-like derivatives. There has been the suggestion that spearmint oil can be an effective treatment for hirsutism in women, otherwise known as "excessive hairiness." Spearmint oil has anti-androgenic qualities, which means it can interfere with free testosterone in the blood. For those women that produce too much testosterone, this might be an effective treatment in reducing the amount circulating in the blood. Unfortunately, there are severe side effects associated with prolonged ingestion of concentrated amounts of spearmint oil such as kidney and liver failure. Until the dose-dependent and long-term effects can be minimized, this treatment won't ever make it on to the approved drug list in any country.
Species name: Mentha x villosa
Common name: mojito mint
Location: teaching lab at Western
Of course, we save the best for last. For those of you that have ever partaken in the consumption of the national drink of Cuba, you will likely have never had it made correctly :) Most places (or people) that make mojitos make it with regular old "mint," which is likely either peppermint or spearmint. This is all fine and dandy, but have you ever had one of those leaves or a piece of a leaf get sucked up in your straw and you have to make the decision to either eat it or spit it out? I bet you probably chose to spit it out, because of the "mouth feel" of the leaf. Both peppermint and spearmint leaves are very hairy, and give you a bad case of the "fuzzy tongue" if you consume a lot of it. True mojito mint, on the other hand, has leaves that are almost completely smooth which completely eliminates the fuzzy tongue feel. A great culinary advancement when it comes to tropical beverages!
This hybrid probably really did arise in the Caribbean, perhaps in Central or South America, and is referred to in Spanish as "yerba buena" or the "good herb" (this is especially true in Cuba). Many species of mint store at least some of their potent essential oils in glandular trichomes on their leaves, which is why they are aromatic just by lightly shaking the plant or touching the leaves. This is not the case in hairless varieties (or species), so the leaves must be treated carefully enough that you don't just get the "taste of plant" when you use them, but rough enough that you actually get the essential oils released from the leaf. This is done by muddling the leaves of the plant with sugar, sometimes alone depending on the species, to get the leaves to release their essential oils. When only using mint as a garnish and not in the drink itself, you always "spank" the mint to get it to release the essential oils.
Mojito mint is an example of a sterile hybrid, so this plant doesn't produce viable seeds (in fact, the plant rarely produces flowers which is also a benefit for those that want to use it for the fragrant leaves). It does still produce those vigorous rhizomes, so care does need to be taken when planting it. This is especially true in tropical and sub-tropical areas as it is drought tolerant, heat tolerant, and has a prolonged growing season which makes it a potentially successful invasive species. This hybrid is actually so vigorous and withstands harsh conditions so well that our plant actually came back after a cold Canadian winter!
Wednesday, August 21, 2013
Species name: Cymbopogon citratus
Common name: lemon grass
Location: teaching lab at Western
Lemon grass (or lemongrass. Same thing) is native to southeast Asia, which should be intuitive for those that cook international cuisine (or local cuisine, I guess, if you're in Thailand or the Philippines!) since it is heavily used in Thai and Filipino dishes. If you've never seen the full plant before (as opposed to just the bulbous bottom of the stalk in the grocery store like in the third photo), you'll notice it looks a whole lot like ornamental grasses you might grow in your garden if you live in temperate North America, like zebra grass (which you can read all about HERE). This species of plant, while not in the same genus as zebra grass, is a close relative and in the grass family.
Like ginger (profiled a few days ago in a blog entry that you can read HERE), lemon grass has a ligule that is useful in identification of the species. It is a very unusual ligule in that there are long hair-like appendages that protrude out of the base of the blade of each leaf, and the papery part of the ligule is short and has nearly a straight edge (which is unusual for a ligule; usually they're longer in the middle than they are on either side and somewhat semi-circular shaped). It's a pretty characteristic ligule, and I'm ashamed to say I didn't get a great picture of it when I had the chance. I'll have to go track down this plant in the greenhouse and make sure I get a good picture of it! Like other grass plants, but unlike ginger, lemon grass has very non-descript flowers that are pollinated by the wind (and that is actually a photo of the flowers in the fourth photograph). This is a characteristic of nearly all species in the grass family, where the amount of resources necessary to allocate to a "pretty" flower used to attract insects or small animals (like hummingbirds or even mice) is far more than it is just to give way to the wind and rely on having your pollen blown from plant to plant. This is partly attributed to the habitat in which most grasses live; wind is abundant in prairie habitats and cheap to use. If you rely on living pollinators to cross-pollinate your flowers, you may run the risk one day of having pollen ready before there are pollinators around to transport it for you. Grasses have evolved "simplified" flowers to eliminate this risk and maximize the potential for pollination. Smart grasses!
As well as the great citrusy flavour lemon grass imparts on food and beverages, lemon grass has been used in folk medicine around the world for centuries. In Brazil it is believed to by an anxiolytic and hypnotic plant, but anyone who has ever had Thai food or lemon grass tea could probably speak to the lack of both of these effects, even when the plant is consumed in large quantities or consumed in a more concentrated form like chewing the stem. In fact, no scientific studies have ever substantiated this claim. Lab studies, however, have shown that this plant has the potential to show some medicinal value. It does show cytoprotective and antioxidant properties, suggesting that this may somehow one day play a role in cancer prevention (no known method of exploiting antioxidants to either prevent aging or prevent the development of age-related cancers currently exists, no matter what anyone tells you). One of the chemicals in the extracted essential oils of lemon grass has been suggested to play a role as an antihypertensive, and in lab studies the pure form, called citronellol, has been shown to lower blood pressure in mice and rats so there is definitely the potential to use this chemical as a potential blood pressure herbal medicine. There have been very few reports of this plant being toxic to any kind of domestic animal (human or non-human pets), so you don't have to worry much if you grow your own lemon grass. Cats anyway will stay away from it because it smells like citrus; unless you've got an atypical cat, cats hate any kind of citrus. Lemon grass oil has been reported to cause mild skin rashes in people with sensitive skin, so if you have extremely sensitive skin be careful handling the fresh-cut plant.
Sometimes extracts from this plant are referred to by the commercial name "citronella," which many of you will recognize as an insect repellant. So does it work? In my experience, no. There is no amount of citronella that you can burn or put on your skin that will truly deter the bugs you are determined to deter: mosquitos (and sometimes deer flies and horse flies). You can never truly "deter" a mosquito. They are out for blood (literally), and "smell" you via the carbon dioxide in concentrated forms that you exhale (which you can't prevent yourself from doing) and by the chemicals you exude in your sweat. Deet is the only chemical that can truly make you "invisible" to mosquitos by camouflaging your scent and throwing off the mosquito's radar. Deet does wear off incredibly quickly, so if you're in an area with a high density of mosquitos you can essentially be guaranteed to be bitten anyway (especially if it's hot and you're sweating, effectively both increasing your hormonal signal to the mosquitos and washing off the deet at the same time). Some people are naturally more alluring to mosquitos because they give off more of the mosquito signal chemical, and so they require more deet more often (I am, unfortunately, one of those people...). By rubbing citronella all over yourself, you're just making yourself smell more like lemons than you are like a human. This can work for about 30 seconds to deter mosquitos, but it is not going to work in the long term. Sorry for ruining your day if you use citronella oil as a bug repellant and have been wondering why you still get bit all this time :)
Does this mean citronella NEVER works against deterring bugs? No, it doesn't mean that. Remember that essential oils produced by plants are secondary compounds usually used in plant defence? Well, it smells like lemons for a reason. Citronella IS actually an effective insect repellant; clinical studies have shown that it is nearly 100% effective in deterring fruit flies from a specific area where it is applied, and it doesn't have to be applied in large quantities. It also does a pretty effective job of deterring stable flies, which bite not only humans but also horses and cows if they get a chance (and these bites are incredibly painful, bloody, and result in enormous welts on the skin). Citronella oil definitely does have a good use in insect deterrence, just don't expect it to do anything for mosquitos!
Sunday, August 18, 2013
Going along with the theme of "plants on display in the lab room of a course I TA," I have a series of three different, yet closely related, plants for this blog. The first one is a plant I've blogged about before, and the next two are unique (and I didn't even know they existed until I started with this course; now I'm trying to track them down to plant them in my garden somewhere!). The first image shows all of them together so you can get a bit of perspective about size difference and how they differ from each other on a "big picture" scale, then I'll profile each one of them separately.
This image gives away a bit of the surprise (hindsight: take the cardboard cheats out of the way before photographing next time!), but the major difference between these three species of geranium is how they smell. The one in the middle is the "ordinary" geranium, and the pots on each side are geraniums that each have unique smells that I force the students to identify (I'm awesome like that; I make my students use their senses in labs...I even make them taste plants! Don't worry, I ask about allergies at the very beginning so I don't kill anyone by accident). So let's get smelling!
Species name: Pelargonium x hortorum
Common name: common geranium
Location: teaching lab at Western
This first plant is probably the most easily identified species of any kind of geranium because they're so gosh darn common! Especially in North America, it seems like everyone, everywhere has planted at least one geranium plant in their garden in the spring (some climates in North America in the southern United States would provide ideal growth conditions to allow for the growth of geraniums all year; they are perennial plants in ideal conditions). The colour of flowers can differ drastically, as can the shape and general morphology of the leaves of the plant. The common geranium is native to southern Africa, where it is actually now nearly threatened in the wild because of habitat loss and the increasing frequency of severe drought. I have blogged about this plant twice before in two different forms; you can read all about the two cultivars HERE and HERE.
The easiest way to identify a "regular" geranium is by looking at the leaves (very fleshy and almost furry on both sides) and the flowers (the characteristic five petals with the stigma in the middle that's star-shaped; you might need to click on the image of the flower to make it larger to see it). Since other species of geraniums are less likely to flower both in general and in captivity (putting other species of geraniums in pots makes them significantly less likely to flower, but they do also have different flowering times so they might not have been "in season" at the time I took these photos), we'll concentrate on the leaves as methods of distinguishing these species.
Species name: Pelargonium crispum
Common name: lemon scented geranium
Location: teaching lab at Western
You can see right away that this species is quite different from the previous, "common" geranium in two ways. The first one is the way that the plant grows. Instead of it being a low, bushy plant, it instead grows thick, woody stems and the leaves are concentrated at the top of these stems. This is partly attributed to the general differences in growth habit of these species, but also a difference in breeding; the common geranium has been selectively bred over centuries to maintain a "low and bushy" growth form because it is more pleasing to gardeners. If you let the plant grow long enough indoors (or live in a climate where this species survives year-round), you'll notice it start to get taller and more wiry as it ages. Pruning can prevent this by keeping the plant short, but since the flowers only emerge from the top of the plant pruning is generally discouraged. It's much easier to just rip it out and replant it if you want to keep it short, or just learn to love a straggly geranium bush.
This species is also native to southern Africa, but is much more common in the wild because of its natural defence mechanism: the scented leaves. The plant hasn't just developed this ability to please humans; it has actually evolved as a way of deterring herbivores from eating the plant. The regular hairs on geranium leaves are called trichomes. The lemon scented geranium also has these trichomes on the leaves, but they also have specialized trichomes called glandular trichomes. These have a swelling at the tip of the hair that contains a tiny droplet of oil. When we separate the bulge from the rest of the hair we get this over-powering smell of lemon (the scent is very similar to Lemon Pledge, if you've ever used that for dusting then you'll recognize the smell immediately), but to a herbivore this means "STAY AWAY!" If a herbivore is silly enough to consume the leaf anyway, then they will in all likelihood be killed (if small) or learn to never do that ever again (if they're larger). The oil droplets contain potent chemicals that are toxic in large quantities; humans would have to ingest an entire plant in order to feel any ill effects so you don't have to worry about any accidental poisonings if you happen to own this plant (there is no reported toxic effects on cats and dogs, but you might want to play it safe and keep them away from it anyway). You will want to be careful, however, with this plant around very young children as the oil in the droplets can be very irritating to sensitive skin (and babies and young children generally have the most sensitive skin, especially on their hands, arms and face). As an aside (a relevant one): I have chewed on one of these leaves just to "try it out," and let me tell you. Not a pleasant experience. It doesn't taste AT ALL like it smells. Word to the wise.
The overall leaf shape of this species is also very different than a common geranium. The leaves are much more lobed than the common geranium, and there is a notch (or a "crisp," where the Latin name of this species comes from) at the end of every leaf vein. They are still fleshy like the common geranium, but another difference between them is that this leaf is much longer than it is wide, where the common geranium has almost a round leaf and at times even wider than it is long in some cultivars.
Species name: Pelargonium grassularioides
Common name: coconut scented geranium
Location: teaching lab at Western
The last plant we have as an example of the diversity of growth form in geranium plants is the coconut scented geranium. This species, also native to southern Africa, is much more common in the wild than the previous two, but not much is actually known about its current state of population abundance and successful reproduction. As it does share a native range with the previous two species, it can be assumed that this species would also be threatened by habitat loss but it can also tolerate much more harsh conditions than the previous two species; it can tolerate growing in really rocky conditions with little soil because of its vining growth habit.
To me, this species doesn't smell too much like coconut unless it's been well taken care of. It smells much more like "chemicals" (the best way I can describe it; it doesn't really smell like any kind of fruit or vegetable or nut). When the plant is happiest, it smells almost exactly like coconut-scented sunscreen (which doesn't actually smell all that much like coconut, but certainly smells like tropical beach!). This is a great example of the properties of secondary compounds, or compounds produced by the plant that are not necessary for survival and often play a role in plant defences. When a plant is under stress, instead of spending a lot of energy making chemicals that it can store in leaves to deter herbivores, it will instead spend all of that energy doing basic metabolic processes like creating sugars and repairing tissues. Once the plant is no longer under stress, it will go back to producing secondary compounds as long as it has the energy to do so. This is a great example of allocation of resources, where the plant almost "decides" where it's best to use energy and what energetically-taxing activities should be avoided. Like me on a vacation: laying by the pool doesn't take a lot of energy so should be done often, walking or running takes a lot of energy so should be avoided :)
The leaves of this species look very similar to the common geranium, but aside from the smell there are a few differences that you can look out for. The first is the texture of the leaf. Instead of being thick and fleshy, this leaf is much thinner and "normal-looking" (which can be seen in the lower photograph where there's a leaf I just happened to catch straight-on from the edge of the leaf). Also, the upper surface of these leaves are completely smooth, unlike the furry upper surface of the common geranium leaf (which may actually vary in hairiness, depending on the cultivar, but will always have at least some hair on the upper surface). The lower surface of this leaf is where all of the glandular trichomes are located. The leaves of this species are also unique in their coloration, regardless of the maturity of the leaf. When very young, the leaf will be much darker green around the leaf veins than anywhere else on the leaf. As the leaf ages (from the middle picture to the bottom one), it becomes much more uniformly green but if you look closely you can still see a bit of a difference in "green-ness" in some areas of the leaf. The last difference with the leaves is the margin or the edge of the leaf. This is a comparison that actually should be avoided, however, as the margins of the leaves of the common geranium can look drastically different based on cultivar.
One of the most easily observed differences between these two species is the growth habit. This species almost entirely lacks a stem; instead there is a dense mass of tissue near the soil level that acts as a stem, and the leaves emerge directly from the level of the soil. All of the above-ground mass is composed purely of leaves. As the plant wants to explore more territory to find more resources, it will create underground rhizomes that will seek out pockets of soil to establish a new basal stem mass to grow new leaves. This rhizome can traverse rock surfaces if needed, and where it is above-ground it will look nearly black because of all of the melanin (yep, the same chemical that your skin makes as a result of skin damage; we refer to this melanin production as "getting a tan") that is produced in the rhizome. This acts as a UV protectant, and can prevent damage to the rhizome as a result of exposure to the sun. Deeply pigmented plant tissues are also generally avoided by herbivores, as digesting melanin is a difficult process and may actually be a toxic process to some insects. I have also tried chewing a leaf of this species, and also not an overly pleasant experience. Gives a much more "fuzzy tongue" experience, so I'm guessing this would suggest it would be toxic in smaller quantities to humans. It would still involve the consumption of a LOT of the plant to produce any kind of ill effects, but best to keep this one more out of the way of children if you can. On the bright side, the essential oils produced by this plant are much less irritating to the skin!
Friday, August 16, 2013
Species name: Zingiber officinale
Common name: ginger
Location: teaching lab at Western
Ginger is one of the most commonly used spices around the world, and one that many, many people love the taste of (you can count me as a non-member of that group; I personally HATE ginger). It is a tropical spice (and hence why it's a spice and not an herb), and is now most commonly grown for export in India, China, the Philippines, and Jamaica. There are many other countries that grow a lot of ginger, but those are countries that also use a lot of ginger in their traditional cooking (Nepal, Nigeria, Cameroon, Thailand and Bangladesh) and so only a small amount of the total harvest would be available for export. Despite being one of the most commonly cultivated spices around the world, very little is known about the wild populations of this species of ginger (there are four other species in the genus that are commercially sold as "wild ginger," but be careful; the native Canadian species known as wild ginger, an unrelated species to this group, contains potent carcinogens and should never be consumed) throughout its native range in southern Asia around Thailand and Indonesia. There is the presumption, however, that the population sizes are declining due to habitat loss.
Ginger was once believed to be closely related to grasses but now has its own order, the Zingiberales, within the group known as Commenlinids. These are a unique grouping of species within the monocots that includes all grasses, bananas and their close relatives, spiderworts, water hyacinths, and the palms. Quite a diverse group of plants, and a group that most people probably never would have assumed went together. I don't know about you, but water hyacinths (popular ornamental pond aquatic plants with a large bulbous "bladder" at the bottom of the leaves to keep them afloat) and palm trees don't belong in the same group of plants in my mind! But when we compare DNA sequences, these groups of plants do, in fact, make a genetically related group called a monophyletic group. Pretty neat what DNA sequence analysis can show us! Is there something, other than DNA sequences, that demonstrate that these seemingly drastically different plants belong in the same group? Well now that we know they belong, we do actually notice some biochemical similarities between these plants. The most striking of these similarities is the production and storage of ferulic acid in the cell walls of the plant tissues. This type of acid is only produced in this group of plants, and the best part about ferrulic acid? It glows under UV-light. Granted, it is produced in such low quantities that even if you put a grass plant or a palm tree under UV-light you wouldn't notice it glowing but this acid can be extracted and concentrated and used to make things glow. Pretty neat! Ginger plants do share many characteristics with grasses, so I can definitely see why it was assumed they must be very close relatives. They both have the same morphological features with leaf growth and development as grasses: the leaf sheath wraps around the stem (and the stem is actually just composed of concentric leaf sheaths that grow inside one another), forms something called a ligule at the top of the sheath that helps prevent the plant from plant diseases (it acts almost like a piece of tape that prevents anything from getting down between the sheath and the rest of the stem and can be seen clearly in the third photo from the top), and the leaf blade which is the "leafy floppy part" that comes off the stem. The most interesting part about ginger and grass leaves is that each species has its own ligule; they're almost like identification "fingerprints" that can be used by botanists to determine species. Pretty neat that no two species have identical ligules.
If you're an avid reader of my blog (which you should be if you aren't!), you'll have noticed something right away, before barely scrolling past the pictures. The last name of this plant, "officinale," must mean it has medicinal properties! If you assumed that, you would be correct. Common ginger has been used for thousands of years as a medicinal plant, reportedly being able to treat anything from dyspepsia to constipation and colic. Modern scientific research today shows that the rhizome of the plant contains a group of chemicals called gingerols, and these chemicals stimulate the digestive system and cause an increased amount of motility of the gastrointestinal tract. Ginger extracts would definitely help with mild indigestion or mild cases of constipation, but more severe gastrointestinal diseases or disorders have not yet been evaluated for efficacy. There has also been a lot of use of ginger in treating muscle pain associated with intense physical exercise (consumed in China during times of intense building in the 1200s to 1800s, and trekking for materials for these construction projects) and arthritis, and this has also been shown to be somewhat effective in clinical trials. When ginger extract is consumed after a workout, muscle pain post-workout can be reduced by as much as 25%. The catch: ginger extract must be consumed daily, workout or no workout, in order for this effect to be noted. In Canada and the United States, ginger and ginger extracts have made it onto the coveted "generally regarded as safe" lists. So does this mean that ginger is completely safe? Well, like all herbal remedies, you should always check with your doctor before taking them. Ginger in particular causes an increase in bile production as a way of promoting faster digestion. This isn't a problem for most people, but those most sensitive to an increase in bile production will report having heart burn after eating ginger. In cases where someone is sensitive to bile in that they commonly get gall stones, eating ginger every day or taking pills of ginger extracts would be really silly because it would exacerbate the problem. Those with ulcers or inflammatory bowel disease may react badly to large amounts of ginger because of the increased stimulation of the digestive tract, but these reactions are rarely enough to land the person in the hospital (but are unpleasant enough that it is rarely done a second time!).
Despite ginger being such an important plant to many countries around the world, it has yet to make it onto any kind of "national or state/provincial plant" list. This is really too bad for ginger; people who only appreciate ginger for its flavourful rhizome will never get to fully experience the greatness that is ginger. The flowers are absolutely stunning to look at (so delicate and almost transparent the tissue is so delicate, hence my difficulty photographing them), but also could practically knock you over with their intense sweet scent. The flowers open in the evening to attract their nocturnal pollinators, and then are wilted and shrivelled before the evening of the following day.
Tuesday, August 13, 2013
Species name: Gossypium spp.
Common name: cotton
Location: teaching lab at Western (first 6 images) and Samana, Dominican Republic (last 2 images)
Cotton is probably one of the most well-known plant products and the single most important plant fibre around the world, yet few people would recognize cotton growing in plant form, let alone if none of the "bolls" (more on that later) were present. Cotton plants are actually becoming more and more popular as ornamental species around the world because of their beautiful flowers which come in a huge variety of colours and sizes (partially dependent on species, but also on cultivar). Most back-yard gardeners would be lucky to end up with actual cotton seeds covered in fibres growing on their plant; cotton crops are the single most susceptible agricultural or horticultural crop to diseases and pests of all kinds: viruses, bacteria, fungi, insects, and even competition by other plants. As I'm sure you can assume now, the crop that requires the most "-icides" in the world is cotton: herbicides, fungicides, insecticides, and fertilizers. This makes cotton growing very, very detrimental to the environment, and there are some interesting side-effects to this type of spraying that I'll talk about later in this blog.
There are four main species of cotton grown around the world, and each one is selected for different reasons. Believe it or not, all four of the commercially cultivated cotton species are now at risk of becoming endangered in the wild because of over-harvesting. For a crop we grow so much of, that's almost hard to believe! Gossypium hirsutum, otherwise known as upland cotton or Mexican cotton, is native to Central and South America and represents 95% of cotton cultivation in the United States (about 80-90% of cotton cultivation worldwide). Gossypium barbadense, also known as extra-long staple cotton, is native to tropical South America and is highly sought-after for creating fine cotton garments and cotton cloth (Egyptian cotton and Sea Island cotton are almost always derived from this species). Unfortunately, it is incredibly difficult to grow because it requires high amounts of humidity in the air, high amounts of rainfall, and full sun to grow properly. This combination is rare in cotton-producing countries; where there is a high amount of rainfall the temperature isn't optimal, and where the temperature is optimal it is very dry. These factors contribute to why this species only accounts for about 8% of worldwide cotton production. Gossypium arboreum, tree cotton, is native to India, Pakistan, and surrounding areas of the Old World. This species was previously used to make fine textiles for traditional garments, but because of its difficulty in harvesting the cotton fibres (there's a reason why it's called tree cotton!) is now only accounts for less than 2% of the world's cotton production. It is still grown in cultivation in some areas in India for its traditional purposes. The last species used as an agricultural crop is Gossypium herbaceum, Levant cotton, is native to Africa and the Arabian Peninsula. While only accounting for less than 2% of the world's cotton production, it was the first cotton species to be represented in art form. It was first noticed by European traveler Sir John Mandeville, who described the growth of the plant as producing a melon-like fruit that when planted grew sheep. I couldn't make this up if I tried. He also drew exactly that: a melon in the ground with roots coming off of it, and the plant above it with a giant sheep growing on top. Granted, this was the 14th century and they didn't know much about basic biology back then, but still. Sheep don't grow on cotton trees! It wasn't until the 1800s that this story was officially deemed a fable; up until then there were actually Europeans that traveled to Arabia and sub-Saharan Africa in search of sheep growing on trees. A bit ridiculous when you look back!
Cotton fibres and the cotton seeds are produced in structures that are commonly termed the "cotton boll." These bolls contain anywhere from four to seven seeds, depending on the species. Each seed is covered in a dense layer of very short hairs called cotton lint, and then that is covered in a thick layer (or thin layer, depending on the species) of very long hairs called cotton linters. When we harvest the cotton from the plant, there is a machine that all of the cotton bolls are fed into that has razor blades that rotate very quickly, literally "shaving" the cotton seed of its fibres. The fibres are shaken, which eventually separates the lint from the linters and the linters are spun into long threads that can be used to make fabric. The longer the linters the stronger and smoother the thread. So what happens to all the rest of the "stuff"? Well, there's definitely a dirty side of cotton production, and that is the sheer amount of chemicals applied to most cotton fields. When the seeds and the plant flesh enclosing the cotton seeds are tested for toxic chemical levels, they are found to be containing dangerous chemicals at levels that are even too high to feed to pigs. This is a shame, because cotton seeds are actually incredibly nutritious, and being able to feed cotton by-products to animals would be a great use of these plant wastes! Today, most of it is either composted or burned. G. hirsutum is one of the species of cotton used most often to produce cottonseed oil, which is often produced from organic or nearly-organic cotton. This type of cotton cultivation results in a severely reduced yield of cotton fibres due to the cotton boll weevil, which uses the flesh around young cotton seeds as its primary food source. This doesn't harm the development of the seed (much), but does severely reduce the amount of protective covering the seed can produce (aka the seed hairs or the cotton fibres).
Aside from the fibre use and the new-found ornamental use that cotton plants have, they have also been used for centuries as a medicinal species. In both South America and in Africa, the leaves of the plant are pounded and ground into a paste and applied to the skin to treat hypertension and joint pain. The ground leaves can also be consumed to treat delayed or irregular menstruation. There is, actually, a high likelihood that this second use would be incredibly effective. Most of the time, especially before the advent of contraceptives, a delayed or irregular menstrual cycle is the result of pregnancy. One of the chemicals contained in cotton leaves (as well as raw cotton seeds and the tissues surrounding the cotton seeds) is called gossypol and it is a highly toxic chemical to all animals with only one stomach (like humans and pigs; cows are ruminants and so are, for some reason, immune to this chemical). The way that this plant is most toxic is as an abortifacient, or an abortion-inducing chemical.
Cotton production does have a dirty little secret in American history, and that is the use of African slaves. People were shipped over to the United States to spend all daylight hours picking cotton in the fields with little to no rest, and were paid meagre wages (if at all). The only reason why the United States is a major cotton producer today is because of their slave use: the more slaves you have, the more cotton you can produce. In fact, cotton production was the single most important driving factor of the importing of African people to the United States. Granted, cotton is no longer cultivated that way today (thank goodness!) and instead is part of a mechanized process. I often wonder what types of crops would be grown in the southern United States if the slave trade had never existed. Would they be as important in the cotton industry? What about peanuts? Or soybeans? All of these crops required a large amount of human input to grow, and so the only reason why they were ever grown is because of the opportunity to use slave labor. Interesting to think how such events in human history (and not just in the United States, but anywhere in the world where people are brought in to perform manual labor and especially farming) can drastically change the product exports from a country!
Cotton is also an important fibre crop in the paper-making industry. Paper doesn't require wood pulp in order to stick together; it can be made perfectly well from an old pair of jeans blended into a very fine pulp! Cotton fibre paper, sometimes referred to as "rag bond" (but not true rag bond as that's made out of linen or flax fibres), is also called archival-quality paper as it strongly resists decay. For every percentage point of cotton fibres in the pulp that goes into making the paper, an extra 1-5 years is added onto the life of the paper. The paper used for printing theses (which my monstrosity of a PhD thesis will be printed on and permanently bound one day) is 95% cotton fibres, so that adds an extra 95-475 years of life to my thesis. I'll have to provide explicit details in my will that once I die someone I know will go back and visit my thesis every few years between 95 and 475 years after I have it printed to see how long it takes before the pages fall apart. A morbid experiment, but could be a fun one!
The "Vegetable Lamb of Tartary," or the Scythian Lamb, as depicted by Sir John Mandeville (left) and Henry Lee (right) (images both from Wikipedia).