Wine? Wine not!

Species name: Vitis riparia

Common name: riverbank grape

Location: Western University campus

The riverbank grape is one of our great native vine species (the other major native eastern North American species to be featured in the next blog, Virginia creeper). It is a very vigorous grower, capable of growing up to the top of a riparian forest tree canopy (not nearly as tall as a "normal" tree canopy of a forest, since trees that live in riparian, or riverbank, areas don't tend to be able to grow as tall). In the southern areas of its native range it can be a real pest species, but here in Ontario other native species are pretty good at competing with it. Some trees have a harder time than others, but non-native species have an especially difficult time with the smothering tendencies this species sometimes has. That being said, as soon as it is transplanted, either naturally via bird poop (the most common animal vector) or "artificially" via human transplantation, into an area of lowland or upland forest the forest canopy can really suffer as a result. It is remarkably good at smothering new saplings before they have a chance to grow tall enough to escape it, and some forests are so thick with grape vines they're impassable. A great example of a species that grows well in harmony with other species in its native habitat, but can become a real pest, even in its native range, if introduced beyond those limits.

The riverbank grape has a bit of a bad rap in Ontario and the northeastern United States, but that perception seems to be changing a bit. In the 1940s and 1950s, the US government (the Canadian government quickly followed suit) decided that riverbank grape vines were a forest pest and that this species should be eradicated. There had been a lot of accidental introductions of this species into areas important in the logging and lumber trade, and if you're allowing a vine to smother your profits you're not a very good businessperson! So instead of just local eradication programs, these programs were carried out across the United States and into Ontario and Quebec, and whenever a riverbank grape vine was seen in a forest (either riparian area or otherwise) it was sprayed with very toxic herbicides. This was very effective at killing the vines, but also equally effective in killing all of the surrounding vegetation and poisoning the soil (both for soil microbes, very important in forest health, but also making it inhospitable to new seedlings). Unfortunately, it was far too late before anyone realized what was happening, so you still find "dead zones" where mature trees escaped the soil poisoning by having a root system vast enough to support itself with un-poisoned soil, but the understory species are completely missing. I have a rather personal connection to riverbank grape, because one of the species of fungi that I study for my PhD grows exclusively on grape vine in North America. Unfortunately, there's a catch (as there always seems to be with rules regarding where fungi are most likely to be found): it only grows on mature, living or dead grape vine. This means that any suitable habitat that might have been in forest ecosystems in the 1800s when a lot of the work was being done on the fungal flora of North America no longer exists for this species. For this reason, it was collected three times in the 1880s by great, now long-dead, mycologists only to never be recorded ever again. Have these species gone extinct because of our destruction of their host species? No one, including myself, knows that for sure. Since the 1930s there has been a lack of concerted effort to document the diversity of forest species, only re-invigorated in the early 2000s. What I can say is that for the last 6 years whenever I'm in a forest where there's grape vine I look for it...and haven't found it yet. Perhaps I'm not looking in the right spot, or perhaps it doesn't exist anymore. I'll let you know in 20 years when I either find it or give up looking. ;) This idea of "disappearing species" is not unique in mycology; there are also a lot of plant species that were discovered during the times of the Great World Explorers (as I like to call them) that have never been found again. Part of the problem stems from the lack of location data for the collections--how do I know where "Aunt Edna's House, near the south greenhouse but past the wood pile, 5 minutes from the beach" is?! Sure, maybe EVERYONE in 1872 knew where Aunt Edna's house was...but it's long gone by now. You don't realize just how useful GPS coordinates are until you have to figure out something like that!

Anyway, back on topic...

Riverbank grape fruits are reportedly edible, and were also reportedly an important food source in the summer for early settlers in North America. Now, I'm guessing that tastes have progressed a bit since those times, or perhaps they were much less picky eaters than we are now (or maybe a bit of both). Have you ever tried a grape from a wild grape vine? They are TERRIBLE. I wasn't expecting a sweet grape when I tried one, but holy jeez. This was...terrible. That's the only way I can describe it. It was gooey and had the most awful texture on the planet (almost like jello on the inside), plus one of the most sour fruits I've ever had in my life (puts the Cornelian cherry to shame, which you can read all about HERE, and I often eat lemons for fun...so that tells you something about my tolerance for "sour"). My friend Tanya convinced me to try one when we were out geocaching one afternoon, and I could taste the lingering "lip-puckering sour" in my mouth for hours. That's the last time I ever listen to Tanya. Ha.

Sure, the grapes don't taste that great and the plant isn't all that much to look at (although, I personally really love the shape of their leaves and the cute little curving tendrils that are most visible during the winter and early spring), riverbank grape is one of the single most important "novelty agriculture species" that we have in North America. I call them an agricultural novelty not because their use is new, but because the product we get from them is certainly not necessary for everyday life (some people might argue with me on that one; we'll agree to disagree) nor has it ever been. Wild grape vines are VERY tolerant to winter conditions in North America, which can be incredibly harsh, especially in the ground. Traditional wine grape vines, of the species Vitis vinifera, don't have a very cold hardy root system, and are prone to freezing damage in northern climates. For this reason, riverbank grape rootstock is often grafted onto a wine grape scion (or "top") for commercial grape production for the wine industry. Once grapevine producers were experts in the creation of natural hybrids, they started experimenting with different varieties of V. vinifera as well as V. riparia to make more cold-tolerant grape vines, but with the same commercial qualities of traditional wine grapes. Another major benefit is that the resulting hybrid is much more resistant to common fungal diseases encountered on grape vines. Eventually what was obtained were varieties that were genetically 50-80% wine grapes, and 20-50% riverbank grape. Baco Noir, Marchel Foch (sometimes called Marechal Foch) and Frontenac grapes are all hybrids between these two species, and produce some of the best wine in the world. Isn't it amazing what a little traditional plant breeding can do?! Cheers to grapes.

Traditional uses by Aboriginal North Americans are also numerous; they are used as a food (although, I'm guessing in small numbers), to make jellies and jams, and to produce a type of traditional North American wine. From what I understand, this wine is really unpleasant when compared to wine from a "real" winery, but it really packs a punch: it has 2-3 times the alcohol content of a traditional wine. Maybe it's alcoholic enough you don't realize how terrible it is! Not commercially sold, but every so often you might be able to find some courtesy of a backyard brewer. Let me know how it is, if you get a chance to try it.

Sandra's Garden: When two become one

Species name: Picea sp. (probably Picea mariana)

Common name: spruce (probably black spruce)

Location: Sandra's garden

The reason why I have no idea what species of spruce these photos represent is because I didn't care to be honest. The trunk characteristics of this tree are far too interesting to care which species it is :) It's either a red, white or black spruce. Black seems unusual due to the height and the general shape of the tree, but white spruces usually have much larger cones than this one has. Red spruce has very different bark...

If you would like to know more about a bunch of different species of spruce, you can learn about the Norway spruce HERE, the Colorado blue spruce HERE, and the black spruce HERE.

So what's so exciting about this tree? This tree has managed to graft itself, then lose one of the scions (the portion of the plant above the grafted location) so that it looks like an upsidedown-Y tree. Normally grafted trees are no big deal. In fact, there are so many grafted trees sold in nurseries unless you really knew what you were looking for you would never notice the difference. A lot of fruit trees, especially those in the rose family (like apples, pears, plums, cherries, peaches, etc.) are grafted because their root stock isn't very hardy. Since the top of the tree essentially "dies" during the winter then is miraculously "revived" in the spring, obviously some part of the tree stays active all winter in order to perform basic maintenance on the above-ground tissues. That's actually the main reason why cryogenically preserving humans can't work yet: when you freeze our bodies, we actually...freeze. Ice forms in our cells, rupturing the membranes. Because our tissues are frozen solid you don't notice. But as soon as the body starts to thaw, the frozen tissue turns to mush and ends up going necrotic (turning black). Bananas do the same thing; that's why a thawed banana isn't a pretty banana! But great for making banana cream pie...but I digress.

Back to roots. Roots stay alive all winter, and the microbial symbioses between tree roots and the microorganisms that live in the soil can actually generate enough heat to melt permafrost in the arctic! That's an impressive amount of heat. The problem is getting the right amount of these symbioses to maintain a ground temperature above freezing so you can heat the rest of the tree by flowing warm water through the vascular system to prevent the tree from freezing solid. Some trees are better at this than others, hence why some trees are winter-tolerant while others are killed when the ground starts to freeze. Members in the rose family have their roots frozen quite easily, so how can we have apple orchards in Ontario? The ground freezes here every winter. The secret is in the grafting process. The scion of the graft is the apple part, while the rootstock is the tolerant of freezing part. The most common trees to use for rootstocks are also "water scavengers" during times of drought; if you've ever had a willow tree in your back yard and have been unfortunate enough to have a sewer running anywhere in the vicinity, you might be aware of what I mean by a "water scavenger". Willow trees are notorious for their ability to break through concrete and colonize sewers with roots in order to absorb more water. What better way to find a water source (unless you're a homeowner...)?! If you want a nice apple orchard that produces juicy apples, putting your apple scions on willow rootstocks seems like a no-brainer and that is how we "make" apple trees. We don't grow them from seeds at all!

So what does this have to do with these spruce trees? Well, usually when you do a graft you start with one scion and one rootstock and you get one plant. If you start with two scions and two rootstocks you get two plants. Three of each? Three plants. These trees, however, fused together then one of the scions was sacrificed, probably by the other one being too "greedy" and taking too many resources during a time of stress. The scion died but the rootstock remained. It should be no surprise that this tree is significantly taller than its neighbours; it has two sets of roots feeding the crown (the top) of the tree! If that's not cool, I don't know what is.

When a flower isn't a flower: part 2

Species name: Euphorbia pulcherrima

Common name: poinsettia

Location: Dominican Republic

The poinsettia, an incredibly popular ornamental plant as both a landscape plant in tropical locations and a potted plant in temperate locations, is native to Mexico and Central America. It is, contrary to popular belief in North America, a tree that can be up to four meters tall. A bit big to fit in a pot! Like many euphorbs, poinsettias do incredibly poorly in pots and shed their leaves quite quickly. This can be due to over- or under-watering, but usually is just a case of the plant being incredibly picky, and not being able to tolerate the short periods of sunlight that it does receive during our winters (8-10 hours of sunlight in a very sunny window versus the 12 hours of sunlight it would receive near the equator), and the temperatures that are much too cold (it prefers to grow at temperatures that average 25 degrees Celsius; much warmer than "room temperature" in the average house in North America during the winter!). This tree in the Dominican was significantly taller than I was, and while it was rather sparse on the green leaves it had enormous clusters of bright red flower bracts, or modified leaves.

Yes, that's right. Poinsettia "flowers" aren't real flowers. Sorry to disappoint you! The true flowers are illustrated in the bottom picture, and even at that they're not fully in bloom yet. The flower buds are the very small greenish pink knobs on the inside of the bracts, and will eventually open into either yellow or white flowers. They are incredibly inconspicuous even when fully open, and do not produce nectar and hence don't attract pollinators (even hummingbirds ignore the bright red bracts). The flowers are, instead, wind pollinated. The bracts also aren't always red, contrary to what we picture the typical Christmas poinsettia to be. They can also be orange, yellow, pink, white, green, and a mottled colouration, usually of pink and white together.

There is quite a bit of speculation about the toxicity of poinsettias, and parents who have "been there" are usually the first to warn you about how deadly this plant is. Well, let me tell you: all lies. Yes, if a small child ate one of the red bracts (or even a green leaf, or chewed on a stem) they would be quite ill with diarrhea and vomiting if they consume sufficient quantities, and learn never to do that again (albeit the hard way). In an analysis of over 26,000 supposed poinsettia poisonings, none resulted in death and only two required hospitalization (likely a hypersensitivity reaction). All were as a result of children and accidental ingestion. Some studies have looked at just how many leaves one would have to consume to die of the latex produced in the bracts, and the results are overwhelming: a 50 lb child would have to eat 500 bracts to require hospitalization due to risk of death from poisoning. That's a whole lot of poinsettia leaves, and I think the real question there if it ever happened would be how a child could get ahold of 500 bracts and be left alone long enough to consume them all. Sounds more like neglect than accidental poisoning! So will having a poinsettia around Christmas potentially kill a curious child? Absolutely not. You should still ALWAYS educate children about putting foreign plant parts in their mouth, because some houseplants are absolutely lethal enough to children to cause death upon consumption, just not this one. If they play with the bracts too much and release too much sap, the latex will cause skin irritation, rashes, itching, and in some children with hypersensitivity reactions to latex, hives. A word of caution: the jury is still out about this plant's toxicity to cats (it has the same reaction in dogs as it does in humans). There are an over-abundance of cases of cats dying as a result of eating poinsettia leaves, and perhaps some of them are true. But I have my doubts about the majority of them, considering how benign they are to humans (I'm guessing the cat probably got into something else that was in the house that led to the cat's death, but that's just speculation). Better to be safe than sorry; if you have a cat, make sure your poinsettia is out of reach to it (perhaps a tall order...literally) or you are vigilant while your cat is around the plant.

The association of the poinsettia to Christmas in the United States and Canada was merely a marketing ploy by a family in California, and a very successful one at that. The plants require a special grafting technique to merge two different species together in order to get the typical bushy plant that you see on store shelves in pots. If left to their own devices, poinsettia plants end up getting rather strange-looking and weedy, as demonstrated in the photos above. Once grafted, they look much more pleasing to the eye. But how to get those red bracts? Because those certainly are not "natural" when grown in North America...or is it? In Central America, because of the 12-hour days, all of the terminal branches have bright red bracts. In order to achieve this, the plants must be exposed to 12 hours of consecutive darkness for two consecutive months, with the other 12 hours being uninhibited sunlight. If any more or any less darkness reaches the leaves, they will stay green (or the plant will just plain old die) and the plant won't be all that attractive. This is the other reason why poinsettias never do well indoors in pots; rarely are they put in rooms that receive total darkness after sunset. I don't know about you, but I like turning on the lights in my living room after dark! The Ecke family business no longer produces poinsettias in California as they had since the early 1900s, but now produces them in the plant's native Mexico. They still serve 70% of the North American market for poinsettias around Christmas. In Mexico, however, this plant has special meaning. The flower bracts radiate outwards like a star, and is said to represent the Star of Bethlehem. Legend also has it that a young girl in the 1600s was too poor to provide a gift to Jesus on his birthday, and instead gathered weeds to lay outside the church. After a few days, poinsettias started to grow and the plants have been incorporated into Christmas celebrations ever since. While not a national plant, it is a very important culturally-significant plant in Mexico.

For part 1 of this blog, about the flower bracts of the bougainvillea, please read the blog post HERE.