The Marvelous in Nature

Trees in bloom

The trees were all in flower when I was at my parents’ last week. Some trees have already flowered and finished, such as the cherry, but most of the trees were just at their peak, or on the downside of flowering but with plenty of blossoms left. I enjoy the flowering trees, and it’s a shame that their blooming period can’t last longer. However, I suppose it makes it that much more enjoyable while they do.

One of my favourites for its gaudiness is the crabapple. The tree in my parents’ backyard must be getting on in years as I can always remember it being there. Yet it continues to put on a good show in the spring. The tree’s proximity to the birdfeeders means it’s usually full of birds of different sorts, and in the spring the contrast of an Indigo Bunting or Blue Jay among the fuchsia flowers is particularly eyecatching.

The flowering trees that we typically think of are all fruit trees of one variety or another. Although many trees “flower”, the ones that produce these large, colourful flowers do so in order to attract polinators. Once the flowers are pollinated they set seed and develop fleshy fruits to attract animals, their primary seed-dispersal method. Other trees with less showy flowers usually develop seed pods or cases. This isn’t an exclusive relationship, however, as there are trees with large flowers that produce seed pods, and fruit-bearing trees that don’t put on gaudy shows like this.

The flowering tree that most people probably think of in the spring is the apple. There are several apple trees on my parents’ property, and all of them are also quite old, by fruit tree standards. Having never been pruned, they’re large, magnificent trees, which flower beautifully in the spring but don’t produce a lot of fruit. The apples they do grow tend to be small and usually slightly bitter; not so appealing to people, but the horses still love them.

The apple blossoms have a single style, the female reproductive organ, in the centre of the flower, surrounded by many anthers. Each flower blossom produces a single fruit once pollinated.

Although superficially similar in appearance, the hawthorn’s white flowers can fairly easily be told from those of the apple tree. They have many styles in the centre of each flower, each of which, when pollinated, produces a seed. The flowers also grow in “corymbs”, or groups, and the hawthorn fruits (called, appropriately, “haws”) form in clusters as a result.

Hawthorns are generally known for the long, sharp thorns they produce, but their flowers can be just as memorable. The hawthorn trees my parents have are also very large, having grown in the open, unobstructed by other foliage.

In the winter I clipped the infected branches from the chokecherry bearing Black Knot, and this spring it’s been blooming prolifically. Unlike the domesticated cherry, both chokecherry and black cherry produce flowers (and subsequently fruit) in long racemes. As a kid I liked to pick the stems of ripe fruit and slide my finger down it to collect a handful of berries; what happened to the berries after was less important, it was the satisfying way they popped off the stem that appealed to me.

This last one isn’t really a tree but a very large shrub, lacking a clear main trunk. The lilac is one of those that doesn’t produce fruit, but instead develops clusters of small seed pods. Like the others, the lilacs near my parents’ house have grown quite large, and over the years have produced fewer blossoms. They remain my favourites, though. I absolutely love the intoxicating smell of the clusters of flowers, and am sad when they finish blooming each spring. Someday, when I own my own house, there will be a large lilac bush planted at the corner.

Merry moths of May

I haven’t posted anything about moths in a little while. Part of this is that there haven’t been many moths to post about. The weather over the last month has been unseasonably cool and rainy. The few nice days we’ve had generally haven’t corresponded with times where I could get out to set up the lights, and the nights I would have had the opportunity to set up, were cold and not good for moths (there was actually frost a few nights ago!).

However, I have done a little bit of mothing. For instance, I went out last night, down to the research station where I set up the trap to leave running overnight since I was going to be in this morning anyway. And since I was down there, I thought I’d stick around for an hour or so and see what I could get in to a sheet. The answer: not too much. I got hundreds of mosquitoes and midges, but moths were scarce. On the other hand, the dozen or so I did get were more than I’d got to the sheet on previous visits to the station. So I shouldn’t complain too much.

The highlight was the above Polyphemus Moth. This giant moth, about the size of my open palm, is a relatively common member of the silk moth family. They have huge, globular, bright green caterpillars that spin large silken cocoons on tree branches (which I wrote about in an earlier post). I’m not sure if this is the actual resident from that cocoon, but I discovered him rustling in the grass not too far from my light, which in turn was not too far from where the cocoon was. One of the things having him up close like that allowed me to notice was that the centres to the spots on the wings are actually transparent. They look like holes in the wings, but are actually clear membrane. This is apparently a feature shared by many of the silk moths. It sounded like it was squeaking while I had it in the net I caught it in, but I’m not certain about that – I found reference to a few types of moths squeaking, but not silk moths.

This is a Black-rimmed Prominent. I discovered it, perched at the edge of the sheet not far from the trap, when I arrived in the morning and went to shut the trap light off and take the sheet down. The prominents are a striking group, many sleekly coloured like this. This particular species is found coast to coast in North America. The caterpillars feed primarily on the poplar family, which is not in short supply at the station.

A couple weeks ago I had a warmish night while at my parents’ and set up a couple of traps to see what I could draw in. It was a pretty good night, with some 30 species of moths. As I was closing up shop for the night, taking down all but the trap, I discovered this guy hanging from the clothesline where I had one of the blacklighted sheets suspended. It’s a One-eyed Sphinx, so named for the single eyespot on each hindwing. The sphinx moths are a pretty neat bunch. Along with the silk moths and the underwings, they’re one of the most frequently observed and tracked groups of moths. There are moth’ers who are crazy about these groups but don’t pay a lot of attention to the smaller, less striking groups. This one was about three inches across or so.

That same night I got this very orange, fuzzy moth. This is a Ruby Tiger Moth. The tiger moths as a whole are generally a very fuzzy group. The adults have fur shawls draped across their shoulders, and (if you peek under their petticoat), furry undergarments. Even the caterpillars are fuzzy. The very common and familiar Wooly Bear caterpillar is a member of the tiger moth family (it becomes the Isabella Moth, a gentle beige moth, very toned down compared to its boldly-pattered larvae). The Ruby is found throughout the northern states and nearly all of vegetated Canada (barren polar ice sheets excepted).

This is another tiger moth, this one the Agreeable Tiger Moth. I’m not sure what specifically about it makes it Agreeable, but it did seem like a very laid back, cooperative moth while I was photographing it. There are a whole bunch of white tiger moths, which are very beautiful in their simplicity and purity. One of my favourite things about many of them are their thighs – in this case, an orangey-brown, but in some they’re bright pink or orange.

And then the week before that, back in early May, I had another pretty good night at my moths, catching a number of new species for me, including this one, the Lappet Moth. The great thing about starting out in something is that everything’s new and exciting. This is not an uncommon moth, but I was nonetheless stoked to catch it because of its really neat appearance. The flanges on its sides are actually the hindwings poking out from under the forewings. It’s found throughout North America, feeding on a variety of deciduous trees.

One last moth to share today. This one, caught the same night as the Lappet, is a Straight-lined Plagodis. I got a second one the following week, as well. Another species found throughout North America, it’s associated with deciduous and mixed forests, the larvae feeding on a number of deciduous tree species. BugGuide.net, one of my primary online reference sources for identifying insects, indicates that it’s also called The Scorched Wing, as stated by the University of Alberta’s entomology department. I rather prefer this latter name myself. There are many moths with very colourful and creative common names, yet another thing that appeals to me about moths. That said, there are some great bird names, too, especially when you get down to the tropics.

Ten weeks in review

At the end of the winter I decided to document the changing of the seasons through spring into summer, following the melting of the snow, leaf-out of the trees and the blooming of the wildflowers. I chose a couple sites to do this at. One was the creek that flows under the road a short distance from my parents’. I cross this creek every time I visit my parents, and for a while I was going there every week or two, so it was a great opportunity, and very picturesque.

This week when I stopped, I could barely see the creek for the trees that had leafed out so completely since my last visit. I felt I’d reached the endpoint, and am posting the series now that it’s finished. Unfortunately, I missed last week, and it seems to have been one of the largest steps. The last photo is rather startlingly green as a result!

March 19

March 26

April 3

April 8

April 21

April 28

May 6

May 11

May 27

Leaves of three

I made a second visit to the site I’m surveying for the City a few days ago. The place was quite active with birds, including a few promising migrants that I hope stick around. The area I’m surveying is primarily open meadow that’s being encouraged to succeed into forest (obviously some decades from now, since the trees being planted are mostly just little seedlings). It’s surrounded by some relatively narrow bands of mature deciduous forest that separate the meadow from the nearby rail lines and road. However, there’s enough remnant forest there to support forest species, including the migrant Wood Thrushes and Ovenbird I heard singing from it.

Since I don’t really venture into the forest during the survey, once I’m done, before I leave, I made a quick foray to poke around. I spotted a few wildflowers I think of as “deep forest” species, stuff that you don’t see outside of the forest interior, including a couple favourites of mine like Bloodroot. And, I spotted this stuff. Poison Ivy. A favourite of hikers everywhere, who often take home more than just fond memories.

I’ve seen some nasty reactions to Poison Ivy, so I was careful to not step off the trail. The culprit causing the ugly rashes is a chemical called urushiol. It’s an oil, found in plants of the family Anacardiaceae. The most problematic genus is Toxicodendron, which includes the dreaded three Poison plants: Ivy (T. radicans), Oak (T. pubescens), and Sumac (T. vernix), the latter being considered by some to be the most toxic plant in the US. Fortunately for me, neither of the latter two occur in my area of Ontario (Poison Sumac does occur in Ontario, but it’s either restricted to the more southern Carolinian forest regions, or it’s local in occurrence and I’ve never encountered it).

Urushiol is an organic chemical with two forms, one saturated and one unsaturated, much like the fatty acids we pay attention to in food. The term “saturated” means that every carbon atom in the molecule has the maximum number of additional atoms attached to it that it can carry. A single carbon atom can make four bonds – some of these may be to other carbon, oxygen, or other atoms, but the rest will be filled with hydrogen. Unsaturated means that the bond between some of the carbon atoms is doubled (they’ve ditched – or never had – the extra hydrogen atoms and instead bonded with each other. Awww…).

Unfortunately, these double bonds can be unstable, and the unsaturated urushiol molecules are the ones that cause the more severe reactions because of the way they’ll interact with our own body molecules. The more unsaturated the molecule, the greater the reaction. A plant’s particular urushiol composition varies from species to species, with the species that cause the worst reactions, such as Poison Sumac, containing the greatest proportion of unsaturated molecules. Less than 50% of people react to saturated urushiol by itself, but over 90% will react to molecules with at least two double bonds.

Poison Ivy has a milder composition of urushiol, such that there are some people who don’t react to the oils. Variably between 15% and 30% of people may not react when exposed to Poison Ivy. I happen to be one of the lucky folks in this segment of the population, as are Blackburnian and my mother. People with hyperactive immune systems can have very severe reactions. An earlier boyfriend of mine fell into this category, and I usually found myself taking care of his clothing for him after he’d had an unfortunate run-in. He could probably have broken out in a rash just by looking at the plant. More sensitive people may find that they react also to other species in the Anacardiaceae family, including mangos (which have urushiol in their skin) or cashews (which have it in the shell).

Unfortunately, just because you’ve not reacted in the past doesn’t mean you’re scot-free. People who are repeatedly exposed to the compound may begin to develop a sensitivity to it, or may find that other plants with stronger urushiol compositions may trigger a reaction. Therefore I don’t intentionally go prancing through the stuff, just to be safe, although I’m usually the person to venture in if it’s unavoidable. Interestingly, the same thing works the other way, too – some people who have reacted in the past may lose sensitivity to it.

Not all animals are bothered by this oil. Birds, for instance, show no adverse effect from exposure, and will happily gobble down the white berries the plant produces in the fall. Pets who run through patches of the stuff will carry the oils back on their fur, which is unfortunate for the owner who unsuspectingly then pets the animal, but does the animal itself no harm. In fact, grazers could eat the plant and not become sick from it. Since the oils are not just present in the leaves, but also in the roots such that pulling it up by hand even in the winter will still give you a reaction, perhaps getting a goat as an organic means of control might be a solution…

So what do you do once you’ve had a run-in with the stuff? Well, for one, avoid hot water which will open your skin’s pores and allow the chemical to sink deeper. It’s an oil, but does dissolve in water (barely), so washing with lots of cold water may help, but will take a while. Using soaps with the water is preferable, to help break up the oil the same way you’d clean your greasy dishes. It’s partially dissolvable in alcohol, which may be another solution. There are some home remedies, too, including the sap from the plant Jewelweed – useful if you find yourself in the bush with no easy access to other options. If you’re not fortunate enough to notice it or be able to do something in time, without treatment the rash will last 3-4 weeks, but will eventually go away on its own. Various creams and salves are available that will soothe the itching and speed up the healing.

Obviously the best solution is just to avoid it in the first place. There’s a rhyme to help you remember – “Leaves of three, leave it be”. I’ve heard tagged on to this, “Leaves of four, have some more”, though this may have been made up by kids as I don’t know if it even references anything. Wikipedia also suggests second-halves of “Berries white, danger in sight”, referring to the white berries of fall, or “hairy vine, no friend of mine”, in reference to the little root hairs that secure the climbing version of the species to a tree trunk or other substrate.

In fact, the three-leaves thing by itself is not useful for identifying the plant (although you’ll be sure to stay away from anything with three leaves, which happens to include Poison Ivy), as there are other species that also have three leaves. I was taught that the three leaves of Poison Ivy droop, rather than being held erect, and that the plant has red stems, but in recent years I’ve begun to wonder about the broad applicability of those statements, and I can find no mention of them on websites.

The main features are the three leaves, the branches for which come off the main stem in an alternating pattern (rather than opposite each other), and that the stem has no thorns (I’m not sure what species does have thorns that it might be confused with). Other look-alikes will either have opposite leaves, or will not be uniformly three-leaved. Poison Ivy is usually bright green in the summer, but can be reddish in the spring and fall. There are two forms, a ground plant and a vine, which are variously lumped into one species or split into two, depending on your source. The ground form can grow as high as waist-height, if conditions are good, and also depending on the particular subspecies.

There are two species of Poison Ivy, an eastern and a western, and between the two they’re found across the continent. The only places to be free of it are Newfoundland, Alaska, California and surrounding area, and northern Canada. The species is more common now than it was historically. It likes forest edges and clearings where it can get a bit more light, and development has helped to create more of this habitat.

Also, a recent study apparently indicates that climate change is having an effect on the plant. The increased levels of CO2 in the atmosphere encourage greater plant growth, with larger leaves, as well as higher urushiol production.

You really have to wonder why a plant would go to the trouble of producing a compound that hardly anything reacts to. And also why most animals don’t react, but humans can react so violently. The plants weren’t talking, though, so it remains a mystery.

A side of mustard

Last year, a new trail system was installed down at the research station. For the first few years the trails we used were just a network of well-worn dirt tracks, tramped down by many feet over many years, in most spots only a single person wide. As part of a park accessibility plan, a new crushed-gravel trail was put in place over the primary dirt ones. The idea is that it’s a wheelchair-accessible substrate, that will allow handicapped park visitors to come see other areas of the park. I think it’s also intended to help better define the trail system to encourage folks to hopefully not wander into the bushes.

When they first installed the trail they had to bulldoze a car-sized wide gouge out along where the new trail was to go. This is a heavy-duty, permanent trail that went in, with a full gravel bed laid down first over which the crushed gravel was placed and packed. As well, an earth bridge with a culvert was placed over the small slough that runs along the peninsula’s length, to connect one side of the trail to the other. The bulldozed section had to be wide enough to accommodate the backhoe and trucks that were bringing in the materials and gravel. It was quite a scene down there for a while while they were working. The final trail was only intended to be about half the width of a dump truck, so after the crushed gravel went down, the sides had to be filled in. Because the area is mostly sand, sand was also used to edge the trail off.

However, at some point late in the summer there was a mixup, and one section was edged with topsoil. It was later corrected and sand put down, but some of the topsoil remained under the sand. It didn’t take long for us to start seeing small sprouts peeking through the sand. I couldn’t tell what they were at the time, but they seemed to be hardy, whatever they were. They grew into small rosettes of leaves that got covered up with snow in the winter. When it melted back they were still there and still green, and I was intrigued to see what they became. As they grew, the winter rosette gradually yellowed and died back and new foliage replaced it.

When they were about six inches tall they started blooming, and I thought they’d reached their finished height. But they continued growing, and some are now over a foot and a half tall. They create a pleasant spray of white-on-green through this section of the trail, and although I knew they must be considered invasive weeds to have sprouted so enthusiastically from some scrapes of topsoil, I can’t help but like the way they look lining the trail.

I took some photos today while I was down there, and using the online wildflower identification key that Jennifer at A Passion For Nature posted about recently, I attempted to figure out what they were. Although my assessment of the size of the flowers was off I did end up finding out what they are. In the above photo you can see two types. The white ones are called Field Pennycress (Thlaspi arvense), and the yellow ones are Yellow Rocket aka Winter Cress (Barbarea vulgaris).

As I suspected, both are introduced species to North America. They’re both originally native to Europe, and could’ve either been escapees from cultivated gardens, or accidentally introduced in cargo shipments, but probably the former – I found no mention of believed release site or information in the bit of searching I did, but did find something that suggested early settlers to North America used the Yellow Rocket to prevent scurvy.

They’re also both members of the mustard family, Brassicaceae. I think of mustards as being these light yellow flowers, similar to Yellow Rocket, but in fact it’s a very broad, widely-encompassing family that includes such well-known plants as cabbage, cauliflower, turnip and radish, as well as garden flowers such as Alyssum and wallflowers.

All members of the mustard family have four-petaled flowers. In the case of the Field Pennycress, the flowers were all somewhat flattened, making it hard to see inside them. For both species, the flowers grew along long stalks, which continued growing from the tip as more flowers were produced. You can get an idea of that here, with the center containing many buds that have yet to develop and the outer flowers growing from different points along the stem.

As the pennycress flowers mature, they begin to form seed pods, and the older flower stems, further down the stalk, support broad, flat, disc-like pods. The plant is capable of self-pollination, so doesn’t require other plants to develop fertile seeds – even though that hardly seemed like a problem here. Once the seeds are mature, the pods brown and drop from the plant, and are blown about in the wind as their primary dispersal method, potentially as far as 1 km (about 0.6 mi) from their parent plant.

Pennycress seeds can last for a long time if buried in the soil. Depending on the depth the seed is buried, it may remain viable for as long as 30 years. I have to wonder just how old these seeds were prior to being spread out along our trail edges.

The Yellow Rocket didn’t seem to be forming seeds yet, but does so and spreads them in a similar manner. Both species are inhabitants of disturbed sites such as roadsides, ditches, so-called “waste” areas, and agricultural fields. They prefer slightly moist soil, but will evidently grow in a variety of soil types, with varying degrees of vigour. Apparently disturbance is a key factor, and neither will grow very well in more high-quality habitats, so while they’re non-native, they’re not particularly invasive, and don’t threaten to run rampant over native species the way some introductions do.

Although the foliage of these plants is apparently edible (stated by a few sites, but also shown by its use as a scurvy-preventative), I didn’t feel tempted to try it. The leaves are apparently quite bitter except when young, and one site noted that the milk from cows that have been feeding on pennycress has a distinctly “off” flavour (this is probably only noticable in small-batch or family-scale milking operations, though).

I’m glad to learn that, although they’re certainly robust, they’re not aggressive species. It allows my mind to rest easier while I’m enjoying them at the trailsides. I know some people take offense to introduced species simply because they’re non-native, but I’m of more a live-and-let-live mindset – if they’re not taking over the place, let’s just leave them be and enjoy them.

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