Things that Gall – plants and parasites

The word “galling” is particularly evocative.  In its most simple form something that galls is merely annoying or vexing, but the true definition connotes annoyance taken to an extreme level.  The sort of thing that will do you no harm but rankles tremendously; much like being forced to pay taxes to support actions you object to.

For us these annoyances are mental and emotional, for plants these galls are physical but are often merely annoyances for them as well.

Dried oak apple gall  on Scrub oak in California

Dried oak apple gall on Scrub oak in California

Many plants suffer from galls and the galls are so singular in form that they can be reliably used to identify individual parasite species.  A fantastic book on identifying plant galls for the California region is the Field Guide to Plant Galls of California and Other Western States.

Oak trees seem to be particularly susceptible to parasites of all sorts and a common manifestation is the Oak Apple Gall, most often seen as a hard, woody ball dangling from a twig.  These galls are created by the Oak Apple Gall Wasp, a common name for a variety of small wasps that inject their eggs into the midrib of a developing leaf and chemically trick the tree into growing a protective shell for the developing larvae.  Despite appearing woody when dried, this type of gall is actually a modified leaf.  The delicacy of these galls is more easily seen when they are still green.

Fresh Oak Apple Gall - Virginia

Fresh Oak Apple Gall – Virginia

The developing wasps browse on the oak tissue and are often preyed upon or parasitized by other animals, including birds, raccoons, and a whole host of insects, other wasps included.  Some insects use the gall for their own protection, sharing the space with the wasp larvae.

Oak Apple Gall with non-wasp larva inside next to a Twig Gall - California

Oak Apple Gall with non-wasp larva inside next to a Twig Gall – California

Certain Oak Apple Galls, the Iron Galls,  in Europe were collected to make ink.  For 1500 years ink make from the iron gall was the primary source of writing quality ink in the Western Hemisphere.  For anyone interested Evan Lindquest provides detailed instructions on how to make your own iron gall ink.

Like may things we have a long history with there is a great body of mythology and folk-lore that has accumulated around these galls.

Many galls are hard and woody, there is a Twig Gall I sliced in half in the photo above.  It appears to be empty, but a dark brown patch filled with frass (insect excrement) can be seen winding its way though the bloated tissue.

Oak Apple Galls often fall from the tree, but Twig Galls are a more permanent fixture of the tree.

Twig Gall on a scrub oak branch flowering from the tip - California

Twig Gall on a scrub oak branch flowering from the tip – California

Right now the Scrub Oak is blooming along the coastal mountains in Southern California.  The twig galls are uniformly clustered near the tips of the branches, with many of them crowned by small clusters of flowers.  This provides a bit of insight into the formation of these and other galls.

The gall must be grown, and while the living plant cells are constantly dividing, the true growth of a woody plant takes place at the tips of the branches and roots, or at the apical meristem of each limb.  The cells in the apical meristem are undifferentiated,having the potential to become a wide variety of plant organs, much like stem cells in animals.  The parasite, be it a wasp, bacteria, or virus, co-opts these “stem” cells and gives them new instructions.  In a way the galls are akin to a tightly controlled cancer initiated by the parasite organism.

The Twig Galls I was looking at today were insect formed and, as such, the insect needs to escape the protective structure once it is mature.  Many of the galls had little holes in them showing where the little wasps has crawled out.

Exit holes in a Twig Gall - California

Exit holes in a Twig Gall – California

The variation in galls is astounding.  I have seen leaf galls on wild roses that look like tiny sea-urchins dipped in vermillion.  There are galls that not only force the plant to grow a protective structure around it, but that trick the plant into producing nectar to attract ants which in turn protect the growing larvae from predators.  Many are extremely colorful and the shapes are widely varied.

Colorful leaf galls on a Sugar Maple leaf - Vermont

Colorful leaf galls on a Sugar Maple leaf – Vermont

The common theme is that the galls are all formed in developing tissue, leaves, new twigs, flowers, roots, or fruit.

A gall on Shadbush fruit - Vermont

A gall on Shadbush fruit – Vermont

Some of the Ichneumonidae wasps that make so many of the galls we see have developed a biological metallurgy, evolving zinc and manganese coated ovipositors which they use to inject chemicals and hormones into the plants they co-opt.

The specificity and regularity of the galls and the relationships between the plants and the gall formers speaks to a lengthy and complicated evolutionary history.

We pride ourselves (or are horrified by) our newly found ability to genetically manipulate plants and animals.  In truth, we have a long way to go before we catch up to what we often mistakenly call the “humble” insects.

Advertisements

Travel Time Again! (remember to say “Yes”)

The trickster gods have been in good moods recently.  Life has been full of interesting surprises, unforeseen opportunities, and things that keep a smile on my face.  The frustration of having my visas delayed for my new job has opened a whole world of opportunities that wouldn’t have been there if the visas had gone smoothly.

A pack of coyotes (Canis latrans) came by to visit for the holidays.

A pack of coyotes (Canis latrans) came by to visit for the holidays.  A blue-eyed one stayed to watch me, perhaps it knew something I didn’t yet know.

Tomorrow, early, much earlier than is comfortable, I head to Spain as a result of several of these unexpected and delightful opportunities.  There I get to mix work with play, experience a new place, and get to know new friends.  From there I head to Indonesia for my new job.

Common ravens (Corvus corax) flying about.  Six of them played on the wind over my head last week for a few minutes before winging off over the mountains,

Common ravens (Corvus corax) flying about. Six of them played on the wind over my head last week for a few minutes before winging off over the mountains,

The visas still are not sorted, but it’s time to move, to see new things, to say, “Yes,” to what is in front of me.

Last time I moved to Asia I flew off into the sunset, heading east, out over the wide Pacific.

This time I chase the sunrise, seeking to lift the curtain of dawn and catch a glimpse of what’s behind it.

My last day in Vermont started with a fabulous rainbow.  It seemed a good omen for the next phase of life.

Rainbow over Hogback Ridge, Vermont on my last day there.

Rainbow over Hogback Ridge, Vermont on my last day there.

I wish you all the best opportunities in the new year and in life with both the wisdom and courage to leap for them when they appear.

If I can, I will post from Spain, otherwise my next post will be from Indonesia.

Fall Color, Superpowers, & Chemistry

My work here in Vermont is drawing to a close and the time is coming to make a transition.  Serendipitously, this is synchronized with one of the more dramatic and beautiful changes that takes place in New England.  Fall Color, the time when the trees reveal their hidden secrets for a brief time before dropping their leaves in expectation of a prolonged period of time when photosynthesis is impractical.

Mt Elmore, Vermont – early fall color

The color is easy to capture at the level of an individual leaf, but surprisingly difficult to capture at a landscape level.   The problem is, like so many things, one of chemistry and individuality.  Not only does each species of tree respond differently to the seasonal changes, each individual tree responds differently, indeed each individual leaf responds differently.  The soil and the weather over the past year have their own influences as well.  This time of year Vermont makes quite a bit of money from tourists, “leaf peepers” they’re called locally.  As with anything that generates money there are numerous conflicting opinions as to what the best conditions are for a good fall color.  The conversations have the flavor of farmers talking about the weather or arguing over the best shape for the bottom of a fence post.

Big Toothed Aspen (Populus grandidentata) leaf against Paper Birch (Betula papyrifera) bark

There are several aspects of fall color I find particular interesting.  The first is that some of the color you see is always there, it is just hidden from view within the leaf by the photosynthesizing portions for much of the year.  I mentioned chemistry.  This is not because I am a chemist, or even particularly knowledgeable about chemistry, but because it is important for understanding much of the world around us.  Chemistry and physics.

Sunlight comes in all colors and some colors (wavelengths) carry more energy than others.  A plant needs to harvest that energy to produce sugars for growth and metabolism.  One of the difficulties the plant experiences is that energy comes in discrete packages, called quantum (quanta plural), and cannot be divided.  I realize that at this point some people will bring up the wave/particle duality issue; very loosely speaking color can be though of as wavelength and quantum can be thought of as the energy each particle carries.

In any event, plants store energy by breaking phosphorous bonds and recombining the atoms in new combinations, especially as ATP.  ATP, adenosine triphosphate, is the battery plants run upon.  Breaking apart molecular bonds takes a specific amount of energy and phosphorous is a particularly energy intensive fuel to use.  This also means that it can store a lot of energy, hence the plant’s use of it.  The degradation of ATP to ADP releases some of that stored energy and powers the plant.  The tricky part is that the light energy the plant has available to it, in the form of discrete quantum packets, does not line up exactly with the energy required to break apart and recombine phosphorus.  And, as previously mentioned, this process takes a lot of energy.

Remember, wavelength is color.  Shorter wavelengths carry more energy, quanta, and longer wavelengths carry less energy (incidentally, measuring this is one of the ways we tell if a star is moving towards or away from us).  Think of a rainbow for a minute…

Summer thunderstorms bring evening rainbows

The red light is low energy, the blue light high energy. Evolution is generally smart and not wasteful, within the limits of the resources it has to work with.  The phosphorous bonds cannot be broken down directly, the plant must convert CO2 and H2O into glucose sugars, metabolize those, and use that energy to create ATP.  All this costs energy, and plants harvest it all from the sun, using much of the red and blue light, and most of the rest of the spectrum except for green (with a few exceptions – purple leaved plants for example use green light).  Blue light causes something of a problem, it is extremely high energy, more than the plant can actually use in most cases.  Excess energy becomes heat, fine if you are in a cold climate, but the bane of existence if you are already in a hot climate.  Too much heat and plants close their stomata to avoid water loss, this also limits the plant’s ability to metabolize or photosynthesize.  One idea of why plants reflect the green light, also high energy, is to avoid overheating.  Green leaves may be a safety mechanism.

Glucose, the initial fuel and energy storage system of the plant, is a relatively relatively simple sugar and sweet to our taste buds.  During fall the plant pulls the important and complex chlorophyll compounds back into the main body, abandoning the leaf, sealing it off with brittle cork-like cells so that the leaf dies and drops away.  As the green chlorophyll leaves carotenoids in the leaves reveal some of the previously obscured color, but something else happens as well.  The glucose remaining in the leaf suffers damage from the sunlight and chemically changes, becoming anthocyanins.  The colors of anthocyanins are influenced by a complex host of factors, but the end result is that they produce fall color.

The second thing I find fascinating about fall color is due to the complexity of factors influencing anthocyanin production and the resultant colors.  Below is an ugly selection of the first Mt Elmore photo I’ve extracted and over-saturated to demonstrate this second interesting aspect of fall.

Note the distinct bands of color

The distribution and pattern of colors reveal soil types and moisture content.  Notice how the colors are not randomly distributed, there are definite bands and patterns?  Color hits first and most intensively where there is some sort of environmental stress.  The two micro-habitats I see changing color first in Vermont are wetlands and well-drained, dry soils.  The upper band of color, below the rock outcrop, is on a slight ledge with extremely shallow soil, land that stays dry and goes through more moisture fluctuations than the land surrounding it.  Each of those patches of color tells you something about the environmental conditions of that area, both seasonally and geologically.

This, to me, is fascinating, it is as though for a short time I have been granted superpowers and have Landsat-like multi-spectral vision.

This time of year in new England is magical.  The nights are cool and the days can be warm, fog rises and the colors are bright.  In the right place mornings feel like something from a fantasy novel, mysterious and beautiful, a place where knights, dragons, elves, or gods might be just around a corner.

Misty lake waters in a New England fall

As the seasons change so does my future.  I have accepted a position in Borneo and will be learning a whole new ecology, a new cycle of seasons, and a new set of environmental cues to pick-up on.  As I make the transition my posts may be a bit rocky and infrequent, and, once at my post, I will be relying on a patchy satellite up-link for a few years, but please bear with me.  Borneo is a rapidly changing place not many people have the opportunity to spend any time in and I intend to share the experience with those who are interested.

Of Woodchucks (and Lawns)

Lawns.  I am not a big fan of them.  I love meadows, or even lightly tended fields.

Summer rain over a Vermont field full of buttercups (Ranunculus spp.)

I prefer to have a yard rather than a lawn, that flat expanse of close trimmed grass we call a lawn has never been all that appealing to me.  A “yard” does not carry the implication of maintenance that a “lawn” implies.  Lawns are an integral part of American life though, and are found even in places completely unsuited to their presence.  In some areas neighborhood associations mandate how your lawn must look, what you can and can’t have on it, and, in extreme cases, what shade of green it must be and how many inches tall it must be.

There are many theories behind why lawns exist, some people claim that it is a relict of animal husbandry, particularly sheep and how a grazed landscape looks.  Others claim that it taps into some deep species memory of living on a savanna, that the flat, open land is visually soothing and  provides a sense of safety and removal from danger and the unknown.  Some claim that lawns are a symbol of our control over nature, our own private, manufactured landscapes.

The most interesting idea I’ve heard for the prevalence of lawns in the US is in Charles C. Mann’s excellent book 1493: Uncovering the New World Columbus Created.  He suggests that wide, expansive lawns may have been an anti-malaria survival strategy.  A house on a rise on the landscape with cleared land around it would catch the breeze and prevent malaria carrying mosquitoes from getting into the house.  Lawns became embedded in the social consciousness of the emerging United States and spread with the population, as symbolic as the flag or fireworks, though more subtle and having greater practical value.  It is an interesting idea and makes as much, or more, sense as any other idea concerning lawns that I have read.

What bothers me about lawns is that they tend to be uniform monocrops with little three-dimensional texture.  This lack of diversity limits what wildlife visits a lawn, and I, as an ecologist and someone who is always investigating things, love diversity.  My yard here in Vermont is diverse, but my landlord likes a short lawn and cuts it down to an inch or two in height.  Every time he does so all the insects, birds, and mammals flee, taking weeks to return.  I like all those mobile visitors.

Dew covered Funnel-Web or Grass Spider webs (Agelenopsis spp.)

One of the visitors to my lawn is a plump woodchuck (Marmota monax).  It only crosses the road to my lawn when the vegetation reaches 6-8 inches, then it visits nearly every evening and some mornings a well.  This rotund fellow is wary and alert, standing up and peering about at the slightest out of place sound.

Woodchuck (Marmota monax) alert for danger

The name Woodchuck is actually a derivative of a Native American name wuchak, and has nothing to do with either wood or chucking, despite generations of woodchuck chucking wood tongue-twisters.

Woodchucks, also known as Groundhogs, Land-Beavers, and, my favorite, Whistle-Pigs are marmots, large rodents related to ground squirrels.  Most of the marmot family are alpine dwellers, commonly found in high grassy places from Europe to Asia and through North America, but the woodchuck is a lowland species wide-spread in the northeastern and central United States, and through Canada up to Alaska.  Like other marmots woodchucks have a piercing alarm call, a sharp whistle that carries far, sometimes with a bit of a burbling quality to it.

Woodchuck from the rear

Most often a woodchuck will appear as a furry lump on the grass, something like a cross of a loaf of bread, a caterpillar, and a fat otter pretending to be a cat.  Many people have a particular dislike for woodchucks because they eat garden vegetables and ornamental plants.  A good friend of mine has been driven to distraction by one that is eating her hydrangeas.  The one that visits my lawn (but only when it has not been cut for a while) eats the dandelions and fleabane, basically weeding the yard for me.

Woodchuck eating weeds from my yard

During the spring, summer, and fall woodchucks pile on as much fat as they can, much like small bears.  Come winter they retreat to a specially dug winter burrow to hibernate.  Marmots are some of the few animals that enter true hibernation.  They radically slow all their metabolic processes and remain oblivious to the world until mating time, often beginning in February or March, possibly later the further north they live.

Woodchucks have marvelously thick and soft fur, as do other marmots.  I have a hat I bought in western China with a marmot fur ruff that is too warm for me to wear in nearly any weather.  Despite putting on a tremendous amount of fat their flesh is lean, most of the fat is in a subcutaneous layer, just beneath the skin, with the rest stored in the body cavity between the internal organs.

Woodchucks are the most solitary of marmots and are said to be aggressive.  They can be hand raised to be cuddly, but it takes a great deal of effort to overcome their feisty nature.

Surprisingly, woodchucks are reputed to be agile climbers in an emergency, though I have yet to see one scale a tree.  Most often what I see is one popping up to look about:

Wary woodchuck watches for danger

Followed by a rapid retreat if I am not careful, quiet, and slow moving:

Just too dangerous around here…

I like this occasional visitor to my yard, and, given the option, do not mow my lawn as if I do it will not come by to visit.

Mainly because it is silly – if the animation is not working, click the image

*     *   ***   *     *

A note:  my posts may become a bit erratic for a few months, I am in the midst of finishing one job, moving (maybe twice), and will hopefully be beginning a new job in a different country.  Eventually this will provide great material for the ongoing exploration of nature, but the route there may be a little irregular and unpredictable.  Bear with it, I will not abandon my writing and photography.

Loons – the clumsy birds

If you’ve spent time on an undeveloped lake in northern North America or Europe you’ve probably seen or heard loons.  Their calls are loud and eerie, ringing out over still water and carrying far before fading amongst the trees.

Here in Vermont the Common Loons (Gavia immer) have finished nesting, the young have hatched, and the adults are teaching their young how to survive.  Over the past few months they’ve flown in from their winter grounds, found nesting spots, defended them, reproduced, and will stay until the first ice begins to cover the lakes.  The adults carry immature young on their backs.

Kevin T. Karlson photography – common loon with chicks

When the time comes for over-wintering loons fly to the oceans.  In the US there is an excellent loon tracking program that allows you to watch the movements of individual loons over the seasons.

Loons are large waterfowl with a distinct black and white pattern, reminiscent of Penguins, Auks, Razorbills, Puffins, Terns, the questionably named Imperial Shag, and a host of others.  These birds are patterned white on the belly and black on the back for the same reason that Orca and other aquatic predators are; from below the white blends into the sky, and from the above the black blends into the water (or ground), providing camouflage from both prey and predators.

Loons are excellent fliers with long, surprisingly narrow wings

Loons are excellent flyer and fantastic swimmers, but have difficulty on the ground.  Their large bodies are front heavy and they cannot stand upright, as a result they push themselves along the ground, sliding on their bellies. The name Loon derives from Scandinavian names for lame or clumsy, “lúinn” in Icelandic and “lam” in Swedish.

Their inability to walk means that their nests must be close to the water and that the nests must be in well protected places, usually islands or extremely wet peninsulas.  As more and more lake sides are developed there is less and less nesting habitat for loons.  In addition a pair of loons needs 5-20 hectares (12-50 acres) of clear undisturbed water on a lake with many small bays and nooks and a healthy fish population.  Boats and swimmers can easily disturb nesting loons and studies indicate large reductions in nesting success in areas where people come into close contact with nesting loons.

There are few places that meet the nesting requirements and loons are highly territorial during nesting season.

Most of the time loons are heard, not seen, and when seen it is usually from at least a mild distance.  Several weeks ago I came across a freshly dead loon on the shore of a small pond.  Finding dead animals is always interesting as you have an opportunity to look at them up close and discover things you wouldn’t otherwise know.

The background of this particular loon is that it was an undersized male, blind in one eye, that (according to the banding codes) was new to the area.  It fought with the male of an established nesting pair and lost the fight.  A fellow from the Vermont Center for Ecosystem Studies moved the loon to a nearby lake where it stayed for several days, seemingly falling into poorer and poorer health until I found it on the beach.  Upon request I collected the loon so that it could be sent to one of the research labs and an autopsy done on it.

Small male loon found dead

Small male loon found dead

The first thing that caught my eye was the sleek iridescence of the feathers, tending towards a blue-purple on the neck and with an oily sheen on the black back feathers, but it was the legs that fascinated me.  Chicken, duck, and most other familiar birds have round legs.  This makes sense, these birds must support their weight while walking, or waddling in some cases.  Loons don’t walk so their legs don’t need to be especially strong side-to side.  They do need to cut smoothly through the water however, and as such they are blade-like in shape presenting a narrow front to reduce drag.

The white neck feathers stand proud from the black feathers

The white feathers that ring the neck stand proud, rising 2-3mm above a background of short, fine, dense black feathers.  Loons are cold weather birds and, like all water birds, they have dense feathers.  I did not realize just how dense those feathers are though.  Loon feathers feel like rich fur, not feathers, almost felt-like in texture and density.

White speckled back feathers

The white speckles on the loon’s back remind me of an Escher print.

Here in Vermont loons are popular animals and there has been some good work done to protect loon habitat.  As a result, loon breeding success is higher in this state than the national average.  Bans on lead sinkers for fishing have helped the loon population as well as fewer individuals are swallowing the lead and getting poisoned from the metal.

Birds, but especially Warblers

Birds occupy a place in our imagination like few other animals.  They are colorful, have beautiful songs, and they can fly!  Who doesn’t wish they could fly?

Young Red-tailed Hawk (Buteo jamaicensis) before the tail turns red

We eat them, decorate our bodies with their feathers, listen to their songs, and keep them as pets.  In westerns the high-pitched keening cry of the Red-tailed Hawk symbolizes the openness and loneliness of the range, setting the mood and implying that the rugged, lone gunman is as comfortable on the dusty range as the hawk is in the air.

Traditional societies have based dances on the mating dances of birds, clothing has been influenced by the color and patterns of birds, and we assign symbolism to specific birds; doves for peace, hawks for aggression, eagles for freedom, the unfortunate dodo as a dead-end in stupidity, and many more.

Here in the US the we chose the Bald Eagle to symbolize our nation, choosing a bird that is at least as much of a scavenger as it is a hunter, over the objections of Benjamin Franklin.  Make of that what you will.

Some birds live only a few years, others like parrots and albatrosses live as long as a healthy human.  Many birds can “fly” under water as well as in the air, the Water Ouzel of the American West, Loons, Cormorants, and Gannets that plunge into the water like falling rockets, diving many meters down to chase fish.  Some birds have given up the air entirely, Penguins retain their flight in the water, but the Ratities, an ancient lineage including Rheas in South America, Ostriches in Africa, Emus in Australia, and the extinct new Zealand Moa returned to their dinosaur origins, running at high speed on the ground, forgoing the air forever.

Corvids, crows and jays, Parrots, and Cockatoos are renowned for their intelligence, problem solving, and in the case of Corvids, tool use.  These birds rival small children and chimpanzees in their mental abilities.

Birds also can tell us about changes in climate and the environment.  Banding them allows for long-term identification of individuals.  Feathers can be analyzed for isotope ratios, telling what the birds have eaten and where.  Populations can be tracked to see how they respond to changes in environmental conditions.

Vermont Center for Ecosystem Studies employee banding a bird on Mt. Mansfield

I am not an ornithologist, I find birds to be largely mystifying.  I don’t seem to have the ear necessary to distinguish species based on their calls, a vital component of birding.  Despite this, I do greatly appreciate birds and try to photograph them when I can, in part to help me learn, in part because they are pretty, and in part because birds are often easier to see and are more prolific than many other animals.

Birding is a popular activity.  Of all groups involved in conservation and outdoor activities, birders have the highest average income, and companies that make the high quality spotting scopes and binoculars necessary for this activity adjust their prices accordingly.  Many of the most interesting and colorful birds are tiny and fast, necessitating patience and luck, or good equipment, or, most often, a combination of the two.

Warblers are popular birds to watch in New England.  New World Warblers are an often colorful group of small passerines, commonly called “perching birds”.  The name derives from their sparrow-like appearance.  Many of the New World Warblers over-winter in the neo-tropics, flying up to New England as the weather warms and food becomes available here.  Most of the ones I see are in the Septophaga genus, meaning “moth-eating”, though this is sometimes misreported as meaning “fly-eating”.  Others fall into the Cardellina and Geothlypis genera.  I am not sure what the origin of Cardellina is.  Several of the birds in this genus are reddish or pink, and others have a lovely song, it may be a comment on a loose similarity to Cardinals.  Geothlypis roughly means “earth warbler”, perhaps reflecting the essential silliness of many scientific names.

Over the last few years I have managed to take photos of a small number of them:

Canada Warbler (Cardellina canadensis)

This lovely little Canada Warbler was on the ridge-line of Shenandoah National Park and didn’t care that I was nearby.  I heard the song and had to hunt a little bit to find him.

Common Yellow Throat (Geothlypis trichas)

This Common Yellow Throat followed me through the woods as I waded through ferns and sedges in a wet wooded meadow near my house.  It didn’t seem afraid of me at all, more curious than anything.  It kept the caterpillars in its beak, suggesting that there was a nest with young close by.

Black-throated Green Warbler (Setophaga virens)

A few months back I heard a soft but rapid twittering in the woods on my morning walk.  Over my head a flock of 5 or so little birds flitted back and forth faster than I could follow.  One of them briefly touched down and held still for just long enough to snap this photo.  From there I was able to figure out that they were Black-throated Green Warblers.

Black-throated Blue Warbler (Setophaga caerulescens)

On our bird-banding day on Mt. Mansfield this little Black-throated Blue Warbler was found in the mist net.

Yellow-rumped Warbler (Setophaga coronata) western subspecies on the sunflower stalk, eastern subspecies held in hands

The Yellow-rumped Warblers may be the easiest of the warblers to see.  They range from California to New England and have been divided into several sub-species that are nearly indistinguishable to my eye.  The eastern variant is known as the Myrtle Warbler (Setophaga coronata coronata) and the western variant as Audubon’s Warbler (Setophaga coronata auduboni), but they are both Yellow-rumped Warblers to me.

Yellow Warbler (Setophaga petechia)

Finally this small Yellow Warbler was in an apple tree in deep shade.  It sat and watched me for several minutes, then flitted away.

Learning these birds has given me a greater appreciation for them, although I must admit that the task of learning these little guys would have been much more difficult if I couldn’t take photos of them and take the time to look closely at their details.

Away Dog! Apocynaceae, the Dogbane family

Near my house, next to the road the ground is sandy with a scattering of pebbles in the mix.  Like much of Vermont what is not bedrock is ground up glacial debris deposited when the vast continental glaciers melted away.  The ground is sandier than most places at my house because I am perched on the southern slope of a small rock outcrop, a place where the downward pressure of the glacier was lighter, water flowed under the ice, and fine sediment was deposited.

In that sandy ground there are wild strawberries, mosses, dandelions, fleabane, hay scented ferns, a few coneflowers, some potentillas, Allegheny blackberry, a little bracken fern, and a small stand of dogbane (Apocynum cannabinum) with delicate pink flowers.

Hemp Dogbane (Apocynum cannabinum)

Before moving to Vermont my only experience with this plant was via books.  I always wondered why it was called Dogbane.  Was it like negative catnip for dogs?  Or was it simply toxic to dogs?  Apparently it is a toxin, and not just to dogs.  Ingestion of any portion can induce cardiac arrest and both the family and genus name literally translate to, “Away Dog!”  Apocynum cannabinum has, thick, milky sap, much like a milkweed, indeed Milkweeds (Asclepiadoideae) are now considered to be a subfamily of the Dogbanes (Apocynaceae).  Other members of the Dogbane family include two of my least favorite plants, Oleander and Vinca, both from the Mediterranean and common in California where they were introduced as ornamentals.  Oleander can be seen in any urban environment in Southern California, most often as a highway divider plant.  The sap is extremely toxic, raising painful rashes, and the smoke can be lethal if inhaled.  Vinca, more commonly known as periwinkle, is  common in Northern California where it invades riparian areas, covering both ground and small trees in a dense, vining mat of glossy green leaves studded with pretty blue flowers.  It is nearly impossibly to eradicate once in place.

In the past some Apocynaceae species were used to make a poor quality rubber, others for toxin to apply to arrows.  Some species produce edible fruit and others edible flowers.  We extract heart drugs from a few of them as well.

The dogbane in my yard, Apocynum cannabinum, is a traditional North American source for extremely strong fiber, hence the “cannabinum ” species name, referring to the hemp-like characteristic of the plant.  Common names run from simply Dogbane, to Indian Hemp, Wild Cotton, and Hemp Dogbane.  The fibers are stripped from the stalk in late fall and can be twisted into a fine, strong cord.  Cords made from dogbane were prized for their great strength and used for sewing, fishing lines, and other work requiring fine cordage.

The Hemp Dogbane ranges from calf high to chest high.  The ones in my yard top out at waist high.  The have an odd branching structure, perhaps best described as irregular opposite.  The main stalk continually divides in a binary fashion, with one side acting as a dominate leader, this pattern is often repeated on the side branches, but in some cases buds on both side of the stem will form side branches instead.  The result is a roughly Y shaped plant that rapidly spreads as it grows.

Apocynum cannabinum whole plant.

The leaves are opposite and the undersides are covered with a fine pubescence.  I expect that the hairy leaves are an adaptation to help cope with moisture stress.  Plants often evolve this trait to create a boundary layer of trapped, still air that aids in preventing moisture from being blown away.  The upper leaf surfaces have a matte waxy texture, a little like nasturtium leaves.  Water beads and runs off of them rapidly.

Apocynum cannabinum leaf hairs

The seeds are held in long, horn-like pods.  This time of year few of the seed pods have developed, but a couple of plants are a little further along in the cycle than others.

Apocynum cannabinum seed pods, not fully developed

Few of the leaves have any insect damage, but the flowers are popular with a number of insect species.  I’ve seen ants, flies, bees, and moths going to them.  Hidden amongst the flowers are predators as well.  The Goldenrod Crab Spider (Misumena vatia) seems fond of my dogbane.

Goldenrod Crab Spider (Misumena vatia) playing parlor games with a fly

Goldenrod Crab Spiders are so called because they often hide amongst the bright yellow flowers of goldenrod, a common meadow plant in New England.  The spiders change color from white to yellow and back again based on input from their eyes.  The yellow color seeps up to stain their carapace, providing camouflage.  When they move to a pale flower the production of this pigment stops and the spiders slowly turn white once more.  Experiments show that the spider will not change color if it cannot see what color plant it is on.

These are not web building spiders, they are ambush hunters, grabbing unsuspecting prey in their wide arms.

The smell of the flowers is odd and difficult to describe, incorporating many scents including a dusty sweetness and a faint rankness like dried meat on the edge of going bad, but they are pretty.