Jewelweed - species profile

 
What: With my last post on poison ivy, I wanted to return to another good friend of mine: jewelweed (Impatiens capensis). In Centennial Woods, we only have spotted jewelweed (the yellow-flowered pale touch-me-not is found on much richer sites). I spent some time observing it while watching the hummingbirds, admiring its simple elegance. The flowers are so rich and ornate, with no shortage of suitors begging nectar. It grows abundantly anywhere there's water so I headed down into Centennial Woods below the sandy slopes and found a great patch to take some photos.

Ecological notes: Much like raspberry stems and boxelder twigs, the stalks of jewelweed have a weird white powdery bloom to them. I still have no idea what the function of these is, so if anyone knows, send me an email! I was told that it was yeast, but some sources say that this is just a myth wine makers false propagated. I would assume it might then have something to do with resistance to predation by insects or maybe it's a fungicide or for preventing water loss? Researchers in Osaka found that the bloom, at least on grapes, is oleanolic acid. They link it to preventing dehydration. Since jewelweed grows in intermittently wet areas, the bloom could prevent the plant from losing water in droughts (like right now) and thus maintain the stem's rigidity. Sounds reasonable. But why would boxelder twigs have the bloom?

Minute hairs on the surface of the leaves trap air and cause water to bead on the surface. When you hold a jewelweed leaf underwater it seems to transform miraculously into silver! These leaves were holding some of that much needed rain from last night. Many other plants do this too, and since it's a pattern we have to have a super cool esoteric word for it: superhydrophobicity (really afraid of water!! aka the lotus effect). Some plants achieve superhydrophobicity by having a dense coating of bristly hairs, others, like lotus, have waxy cuticles. Supposedly this is linked with both water retention as well as being able to wash leaves clean, even with dew. Since the water beads up it has a high internal charge and will pull dust and other stuff off the leaf surface. 

Yesterday I was noting that many had the malformed flowers, or galls. Inside that green blob there's a Jewelweed gall midge (Schizomyia impatientis). They hatch early fall and overwinter as adults. 

Where: There's a great patch of the spotted kind in CW where an intermittent stream drains off the slope (it's been dry most of the summer though) and you can follow the flow of the water by where the jewelweed grows. Jewelweed definitely prefers wetter areas. So when you find poison ivy, often times walking downslope or finding a drainage will yield a good patch of jewelweed.

Other notes: Jewelweed is pretty easy to cultivate. It's herbaceous, so it dies back every year, but it has perennial roots so it shoots up from the same spot each year. The seeds are spring loaded so when you touch them they erupt out from the pod (see the image of a swollen pod above). They're just now ripening. Seeds taste like walnuts and they've got about 3-5 per pod. Because they shoot so far they'll easily colonize a nice little patch. Ask Zac to see his jewelweed garden started from a single plant!

Hummingbirds

Female ruby-throated hummingbird (note white tips on tail)

Visiting purple loosestrife

What: The second half of the last post is a delightfully little bundle of energy! Ryan and I had headed down to the powerlines after Jon told us about how many hummingbirds there were. I have been waiting for the spotted jewelweed (Impatiens capensis) to blossom, as each summer around mid/late August we get a flush of ruby-throated hummingbirds (Archilochus colubris) feeding on the nectar.

Ecological notes: Any hummingbird gardening guide lists jewelweed as a must (apparently ruby throated hummingbirds prefer spotted jewelweed to yellow jewelweed, I. pallida). Bumblebees and some butterflies also visit jewelweed flowers, but they're not nearly as effective at pollinating the plant, indicating that an evolutionary relationship might exist between the morphology of the flower and the feeding behavior of hummingbirds. I found some interesting notes about the relationship between the two, with unsupported claims that the weak petiole of the flower allows the plant to bend away from the hummingbird's advances, thus protecting the plant's ovaries from the long sharp piercing bill of the bird. Problem is that the complex shape of the flower places the ovaries at the back of the flower, well out of reach of the bird.

Research out of UMass Amherst indicate another, more likely possibility. Jewelweed flowers have flexible pedicels (stems) that allow the flower to bend readily. When feeding, hummingbirds flick out their tongue to slurp out the nectar. Each time the bird does so the weak pedicel allows the flower to recoil back in response and before flapping back forward. As it springs forward the flower dusts its pollen across the upper bill of the bird. It all happens in a brief second, so it's difficult to observe, but the tight relationship is enough to ensure successful pollination. To test this relationship, the researchers immobilized some flowers by wrapping wire around their pedicels. The rigid flowers were far easier for the hummingbirds to suck nectar from (visits were 25% shorter to these flowers), but significantly decreased pollen transfer (by about 50%). They also found that the stems of the flower didn't move when visited by bees, indicating that this is indeed an adaptation specific to hummingbird foraging behavior.

According to the researchers, there may also be a link between the shape/size of the spur (the hook at the back of the flower) and which pollinators (bees vs. birds) go after the individual flower.

Where: Centennial Woods, powerline

Other notes: Summer is coming to an end - you can feel the first crisp coolness of the night air. Queen Anne's lace is going to seed, morning glories and bind weed flowers are out in full force, fruits are ripening (go harvest wild grapes!), Jerusalem artichoke is flowering, and the birds are getting antsy ready to head south.

Jewelweed & Poison Ivy

What: I got poison ivy (Toxicodendron radicans), at least I think I did, this year for the first time ever. I know I've been exposed to it numerous times before so I was disappointed that I might have finally reacted. This year I thought I'd try what Eric Garza (http://path2resilience.com/) had mentioned to me a few years ago: nibbling a bit of the leaves to build up immunity. I started small, with a bit no bigger than my pinky nail. I waited a couple of days without reaction and nothing happened so I ate another one of the small leaves. That was two days ago and I'm still here. I'll try one more small leaf this year and see if I react to the plant again.

An old timey journal says that anything alkaline (or basic) will temporarily alleviate symptoms but does not grant long-term immunity to poison ivy (Dr WF Dieffenbach's "Treatment of Ivy Poisoning" in Southern California Practitioner v.29). The author describes his experience developing a strong adverse response to poison ivy, finding out about auto-lacto therapy (drinking milk of an animal that had grazed on the toxin), and testing the treatment with success. He fed a cow grass and poison ivy then consumed a pint a day for two days. That year he developed no further rashes. In following years he developed a rash again, indicating that immunity is not permanent and follow-up treatments are required. Admittedly the article is quaint in its anecdotalness (it was published in 1917), but warrants a closer look at treatments for ivy poisoning. **It is appropriate to note here that the plural of anecdote is not data. Also pertinent is that I'm not an apothecary, healer, or medical professional and I only recommend doing this after doing your own research/asking the plant itself.

Ecological notes: Centennial Woods is filled with poison ivy, as are most places that are wet, but well drained, and rich, but not excessively so. As is convenient with mugwort growing near poison oak out west (mugwort can be used as a poultice to treat the itchiness caused by urushiol in poison oak), here in New England jewelweed (Impatiens capensis and I. pallida) almost always grows near poison ivy (but the reverse is not true as poison ivy is much less common).

Where: The photos are from Centennial Woods. Below are a couple of look-alikes, at least in the early stages. On the left is sarsaparilla, which has 3-5 leaflets, doesn't have a woody stem, and splits into three branchlets. On the right Virginia creeper (Parthenocissus quinquefolia), which has suction like discs on the ends of their tendrils and five, not three leaflets.

Warning: While I've seen catbirds eat poison ivy berries with gusty, people should never eat older leaves or berries and definitely don't burn poison ivy. If you do try eating young leaves or milk from goats be extremely cautious. Only try exceedingly small amounts at first. And most importantly, do your own research. I'm quoting stuff that I found that proves what I want to believe, I'm sure there's a thousand other anecdotal sources out there that contradict what I've written.

Other notes: Poison ivy is in the same genus as other toxic plants like Poison sumac (T. vernix), poison oak (T. diversiloba out west and T. pubescens out east). The genus is in the Cashew family, Anacardiaceae, which also includes staghorn sumac (delicious) and, not surprisingly, cashews. Members of Toxicodendron are occasionally placed in Rhus, the same genus as staghorn sumac.