That would be a species anyone would be well-advised to learn before traipsing around northern California / southern Oregon: Rhus diversiloba | Landscape Plants | Oregon State University aka poison oak.
I didn't know it was poison, I always wondered how it looks. I don't remember if I touched it, probably not. Thank you
Well, I'm just writing from experience ;-) Poison oak is fascinating (as is poison ivy for that matter) in that it can look very different in different environments across its range. Three leaflets and glossy-looking are a "don't touch", to be on the safe side.
did you need any treatment after your experience with this oak? Do we have any benefits from this plant?
It was poison ivy I had, but the same compound is in poison oak. After the dull pain and weeping skin became too much, I did eventually go to the hospital one of the times (but they didn't do much). I've variously used calamine lotion, some of the oat-based products from Aveeno and Tecnu medicated poison ivy scrub. I don't really have a recommendation, though. The only benefit I can think of is that it keeps people away from trampling some places where rare plants can be found!
Very strange that two such unrelated plants, an ivy Hedera and an oak Quercus should share the same compound — if to the exclusion of other species in the same genera, a remarkable case of convergent evolution. Or is it just a bad case of creationist naming to obfuscate evolution?? Something we really shouldn't be encouraging on a science-based forum ;-) The hyphen is your friend: Poison-ivy Toxicodendron radicans and Poison-oak Toxicodendron diversilobum, to indicate that they are not an ivy and an oak, respectively.
You know, there's plenty of obfuscation in the botanical names. If these things are going to keep changing their name (not to mention their sex - which is it: Rhus diversiloba or Toxicodendron diversilobum?), it's just as well that there are common names people can remember. I'll bet no-one ever has said "I had a bad case of Toxicodendron diversilobum". If you query "poison-ivy", it gets converted to "poison ivy". Though you'd like it to be distinguished by the hyphen, "poison-ivy" doesn't seem to be a thing. Fair enough to call Nadia out on her use of the word "oak" alone. Way off topic, I checked Google to make sure it wasn't only Bing that wasn't returning anything on poison-ivy. The Google doodle today is on the 117th birthday of the influential filmmaker and visual artist Oskar Fischinger. If you're reading this after today, the link is Oskar Fischinger’s 117th Birthday. You have to click the doodle again on the first page it comes up on to get to the actual animation. If you change the instrument at the top, it's more convincing that you're actually affecting the sound.
I actually do approve of this as a general rule for common names. We added common names to our labels a year or two ago, so I have to deal with them now. There are issues around common names and ambiguity. I can't really expect the average Garden visitor to recognize the Latin botanical names of our plants anymore than I would recognize the proper names for animals at a zoo though, so I get their use. It's true Search Engines seem to remove the hyphen from poison-ivy, but GRIN seems to use this format for common names. Taxonomy - GRIN-Global Web v 1.9.8.2 I am going to use that concept for our common names. Certainly it makes sense for people who are only casually familiar with plants to call them something related to plants they already know. In fact this often is the basis of many botanical names. In the end I have to choose what seems to be the most commonly used name, but general rules like this seem helpful in recording understandable common names.
I know this probably doesn't belong here, but regarding common names: if we are concerned about ambiguity, we should just refer to a plant's binomial name (common names are why scientific names were invented). Others are welcome to hyphenate away, but I don't have any problem with poison oak, poison ivy, poison sumac, western red cedar, eastern red cedar, yellow cedar, Vietnamese golden cypress, Monterey cypress, kauri pine, Wollemi pine, (New Zealand) bog pine, western hemlock, poison hemlock, Douglas fir, water parsnip, horse chestnut, American chinquapin (the chestnut), bedding geranium, ivy-leaved geranium, traveller's palm, blue-eyed grass, cat tail, etc.