Toxicodendron radicans rydbergii -- western poison ivy, South Boulder Creek Trail, Boulder, Colorado, July, 2015. As I was taking the picture, a little voice approached me and asked, "Do you know —? Is that —? Could that be —? Poison ivy?" Yes, and it was one of the lushest fields of poison ivy I have seen this side of New Jersey, growing right along the trail. You can identify it because it has 3 leaflets, and often the outer ones are shaped like mittens, though not as distinctively as these. Poison ivy is red only in the fall; we will see that in 2 weeks.
22 Comments
JimboK · 23 November 2015
Soooo...
Refresh my memory, how does "Intelligent Design Theory" explain my horrible allergic reaction to urushiol sap in Toxicodendron sp.???
Karen Spivey · 23 November 2015
Refresh my memory, how does âIntelligent Design Theoryâ explain my horrible allergic reaction to urushiol sap in Toxicodendron sp.???
The same way they explain everything else. God did it. God designs humans. God designs malaria. Malaria kills humans. Any questions?
(Happy itching!)
Michael Fugate · 23 November 2015
Hmmm, Toxicodendron radicans not reported from Colorado, but Toxicodendron rydbergii is.
Refresh my memory, how does âIntelligent Design Theoryâ explain my horrible allergic reaction to urushiol sap in Toxicodendron sp.???
The same way they explain everything else. God did it. God designs humans. God designs malaria. Malaria kills humans. Any questions?
(Happy itching!)
You are insisting that they play the naturalist/materialist game of giving petty details.
We cannot expect to understand the ways of the Intelligent Designers. That does not mean that we don't discover that that there is design, however, whatever, whenever it happens.
Joe Felsenstein · 23 November 2015
We don't have it out here (poison oak instead, but mostly out on the Pacific coast). But I vividly remember how to spot it from painful experiences in my childhood on the East Coast.
When I had a postdoctoral fellow from Switzerland in my lab a few years ago, and we both went off to the same meeting in Georgia, as we walked down the street there I found myself pointing out to him that "there's Poison Ivy, and that's Poison Ivy too, and that too ..."
Matt Young · 23 November 2015
Hmmm, Toxicodendron radicans not reported from Colorado, but Toxicodendron rydbergii is.
T. rydbergii, or western p. i., which I have never heard of before, seems more widespread than T. radicans. Wikipedia says that T. rydbergii is a shrub. This specimen was a ground cover. How do I tell them apart, given that I do not plan to touch any?
fnxtr · 23 November 2015
Here in the Pacific northwest we get devil's club. Much easier to spot.
Henry J · 23 November 2015
Karen Spivey said:
The same way they explain everything else. God did it. God designs humans. God designs malaria. Malaria kills humans. Any questions?
In this case, God may even have designed it from scratch.
Paul Burnett · 23 November 2015
Matt Young said:
Poison ivy is red only in the fall...
Years ago, in the fall, using the best biological warfare isolation techniques, I made a Christmas wreath using the bright red leaves of California poison oak. Most folks were impressed, a few were horrified.
Yardbird · 24 November 2015
Matt Young said:
Hmmm, Toxicodendron radicans not reported from Colorado, but Toxicodendron rydbergii is.
T. rydbergii, or western p. i., which I have never heard of before, seems more widespread than T. radicans. Wikipedia says that T. rydbergii is a shrub. This specimen was a ground cover. How do I tell them apart, given that I do not plan to touch any?
I saw a lot of it when I grew up in Ohio, but I don't know what type it was. In scouts we had to identify it both as a shrub and ground cover. I've always thought its conformation depended on where it was growing.
Kevin B · 24 November 2015
Henry J said:
Karen Spivey said:
The same way they explain everything else. God did it. God designs humans. God designs malaria. Malaria kills humans. Any questions?
In this case, God may even have designed it from scratch.
But was there poison ivy in the Garden of Eden, or was there a second week of creation after the Fall?
Karen Spivey · 24 November 2015
But was there poison ivy in the Garden of Eden, or was there a second week of creation after the Fall?
Yes, it was there, but it was a nice, friendly plant. You could even make a salad out of it, or give it to dinos as a treat.
Dave Lovell · 24 November 2015
Matt Young said:
Hmmm, Toxicodendron radicans not reported from Colorado, but Toxicodendron rydbergii is.
T. rydbergii, or western p. i., which I have never heard of before, seems more widespread than T. radicans. Wikipedia says that T. rydbergii is a shrub. This specimen was a ground cover. How do I tell them apart, given that I do not plan to touch any?
"So that's what it looks like" was my first thought on seeing this picture, and then you go and complicate things in the comment thread Matt. This reaction was triggered by memories of my first trip to Silicon Valley in the mid-80s. Doing a bit of sight-seeing around the base of the southern tower of the Golden Gate Bridge I was struck by the futility of putting up several alarming signs stating "Beware, Poison Ivy", without including anything to tell me what it looked like!
Michael Fugate · 24 November 2015
Here is one key: https://gobotany.newenglandwild.org/dkey/toxicodendron/ here's another: http://fm1.fieldmuseum.org/keystonature/anacardiaceae/
radicans is supposed to have aerial roots and climb.
Matt Young · 24 November 2015
You have to navigate that second link to here. I presume it is T. rydbergii, but I will have a closer look for aerial roots next time I am on that trail. It looked more like a ground cover, though, than like a shrub.
I have another botanist friend who suspects they [eastern and western poison ivy, Atlantic and Pacific poison oak, and poison sumac] might all four be the same plant just adapting to the climate and soil by growing differently. Have to get some DNA testing going here.
Biologists?
https://me.yahoo.com/a/GQ2PdCNxj48x_4wgJHDmevkyD3r_p5YA#ff82e · 26 November 2015
Matt Young said:
Hmmm, Toxicodendron radicans not reported from Colorado, but Toxicodendron rydbergii is.
T. rydbergii, or western p. i., which I have never heard of before, seems more widespread than T. radicans. Wikipedia says that T. rydbergii is a shrub. This specimen was a ground cover. How do I tell them apart, given that I do not plan to touch any?
It's even harder than that, depending on your location. I grew up in south Louisiana, and there, poison ivy can be either a climbing vine, a shrub, or even a small upright tree. What was weird was seeing a poison ivy vine spiraling up around the trunk of a poison ivy tree.
DS · 26 November 2015
Matt Young said:
I just happened upon a site called Poison Ivy, and they remark.
I have another botanist friend who suspects they [eastern and western poison ivy, Atlantic and Pacific poison oak, and poison sumac] might all four be the same plant just adapting to the climate and soil by growing differently. Have to get some DNA testing going here.
Biologists?
There is a paper that sheds light on the evolution of the group using nuclear and chloroplast sequences, Nei et. al. 2009. Here is a link:
http://onlinelibrary.wiley.com/doi/10.1111/j.1759-6831.2009.00045.x/full
The paper seems to indicate that the group is monophyletic but that the divergence between the different species is ancient, about 13 million years. The paper also discusses the geographic distribution.
Hope that helps.
Rann · 27 November 2015
Like Masked Panda's experience, here in southern Canada the stuff comes in a myriad variety. For those who want to see check out this page with all its many links to even more photos.
I used to run through huge patches of it it as a kid with nary an itch....... until the summer I was 17! By the time I realized what was going on, it had spread to EVERY part of my body touched normally EXCEPT the soles of my feet and palms of my hands. One recent new product that is available is a gel soap called After Ivy by Tender Corp. It does a good job neutralizing the urushiol oil, even after blistering has occurred.
The hot summers we have had recently has been perfect weather for its spread here in Ontario. I participate a re-enactment camp in Niagara On The Lake each year...the small patch of Poison Ivy was static in size until a few years ago....then it took off. Parks Canada worked to eradicate it with RoundUp..... but they also tilled up the ground 6" deep to cut up the hundreds of rhizomes growing beneath the surface, and again treated it with Roundup.
Overall, one nasty plant...only rivalled for nastiness by the Giant Hogweed Heracleum mantegazzianum
MichaelJ · 27 November 2015
We don't have Poison Ivy here in Australia but I get very bad contact dermatitus from Grevillia. I've read that the effect is the same and I sympathise with those afflicted.
fusilier · 30 November 2015
Leaflets Three, Let It Be!
That's all you need to know. Daughter #2 earned her very first merit badge in Girl Scouts for grabbing the scout leader and pulling her away from a patch growing in the scout leader's suburban back yard.
She was six at the time, but we'd been doing primitive camping since she was still in diapers.
A propos of boots, there's a particular Japanese wood-finishing technique which uses an urushiol-based lacquer: https://books.google.com/books?id=R1_7z2MeZOMC&pg=PA195&lpg=PA195&dq=urushiol+japanese+finishing&source=bl&ots=sqMKyQ4yXm&sig=eNQkIv2JHLA1VJ6XNElR7DuZ7N8&hl=en&sa=X&ved=0ahUKEwjs7eirtbjJAhXIGx4KHffBB4sQ6AEILTAC#v=onepage&q=urushiol%20japanese%20finishing&f=false
(hope that url works)
fusilier James 2:24
Shebardigan · 1 December 2015
"Leaflets three? Let them be! Berries white? Poisonous sight!"
22 Comments
JimboK · 23 November 2015
Soooo...
Refresh my memory, how does "Intelligent Design Theory" explain my horrible allergic reaction to urushiol sap in Toxicodendron sp.???
Karen Spivey · 23 November 2015
Michael Fugate · 23 November 2015
Hmmm, Toxicodendron radicans not reported from Colorado, but Toxicodendron rydbergii is.
http://www.fs.fed.us/database/feis/plants/shrub/toxspp/all.html
TomS · 23 November 2015
Joe Felsenstein · 23 November 2015
We don't have it out here (poison oak instead, but mostly out on the Pacific coast). But I vividly remember how to spot it from painful experiences in my childhood on the East Coast.
When I had a postdoctoral fellow from Switzerland in my lab a few years ago, and we both went off to the same meeting in Georgia, as we walked down the street there I found myself pointing out to him that "there's Poison Ivy, and that's Poison Ivy too, and that too ..."
Matt Young · 23 November 2015
fnxtr · 23 November 2015
Here in the Pacific northwest we get devil's club. Much easier to spot.
Henry J · 23 November 2015
Paul Burnett · 23 November 2015
Yardbird · 24 November 2015
Kevin B · 24 November 2015
Karen Spivey · 24 November 2015
Dave Lovell · 24 November 2015
Michael Fugate · 24 November 2015
Here is one key:
https://gobotany.newenglandwild.org/dkey/toxicodendron/
here's another:
http://fm1.fieldmuseum.org/keystonature/anacardiaceae/
radicans is supposed to have aerial roots and climb.
Matt Young · 24 November 2015
You have to navigate that second link to here. I presume it is T. rydbergii, but I will have a closer look for aerial roots next time I am on that trail. It looked more like a ground cover, though, than like a shrub.
Matt Young · 25 November 2015
https://me.yahoo.com/a/GQ2PdCNxj48x_4wgJHDmevkyD3r_p5YA#ff82e · 26 November 2015
DS · 26 November 2015
Rann · 27 November 2015
Like Masked Panda's experience, here in southern Canada the stuff comes in a myriad variety. For those who want to see check out this page with all its many links to even more photos.
I used to run through huge patches of it it as a kid with nary an itch....... until the summer I was 17! By the time I realized what was going on, it had spread to EVERY part of my body touched normally EXCEPT the soles of my feet and palms of my hands. One recent new product that is available is a gel soap called After Ivy by Tender Corp. It does a good job neutralizing the urushiol oil, even after blistering has occurred.
The hot summers we have had recently has been perfect weather for its spread here in Ontario. I participate a re-enactment camp in Niagara On The Lake each year...the small patch of Poison Ivy was static in size until a few years ago....then it took off. Parks Canada worked to eradicate it with RoundUp..... but they also tilled up the ground 6" deep to cut up the hundreds of rhizomes growing beneath the surface, and again treated it with Roundup.
Overall, one nasty plant...only rivalled for nastiness by the Giant Hogweed Heracleum mantegazzianum
MichaelJ · 27 November 2015
We don't have Poison Ivy here in Australia but I get very bad contact dermatitus from Grevillia. I've read that the effect is the same and I sympathise with those afflicted.
fusilier · 30 November 2015
Leaflets Three, Let It Be!
That's all you need to know. Daughter #2 earned her very first merit badge in Girl Scouts for grabbing the scout leader and pulling her away from a patch growing in the scout leader's suburban back yard.
She was six at the time, but we'd been doing primitive camping since she was still in diapers.
A propos of boots, there's a particular Japanese wood-finishing technique which uses an urushiol-based lacquer:
https://books.google.com/books?id=R1_7z2MeZOMC&pg=PA195&lpg=PA195&dq=urushiol+japanese+finishing&source=bl&ots=sqMKyQ4yXm&sig=eNQkIv2JHLA1VJ6XNElR7DuZ7N8&hl=en&sa=X&ved=0ahUKEwjs7eirtbjJAhXIGx4KHffBB4sQ6AEILTAC#v=onepage&q=urushiol%20japanese%20finishing&f=false
(hope that url works)
fusilier
James 2:24
Shebardigan · 1 December 2015
"Leaflets three? Let them be! Berries white? Poisonous sight!"
-- Something from Cub Scouts back in the '50s.