I am a self confessed, indeed proud, pedant (did I hear "you don't say?")
I was reminded of this tendency reading the whimsical Back Pages section of New Scientist a while back. In an earlier edition of the mag there had been an aside noting that "botany is a rose garden filled with thorns", a combination of words that would apparently mean something to Taylor Swift fans*. In an admirable bit of pedantry a reader had written in to point out:
"Sorry, but botany is not a rose garden filled with thorns, unless you've got shrubs like blackthorn. Roses do not have thorns but prickles which are superficial epidermal outgrowth whereas thorns are modified stems."
The sharp bits on roses aren't attached very firmly to the stems - you can easily snap them off from the stem sideways. So, while one might give you a nasty scratch the sharp bits on blackthorn or pyracantha are a very different matter, being firmly part of the stem of the plant. They don't snap off and so are capable of sticking much further into your soft tissue if you take liberties.
So roses have prickles, not thorns. Who knew? And who's going to tell Will Shakespeare, who says in sonnet 35:
No more be griev'd at that which thou hast done
Roses have thorns, and silver fountains mud.
I have a strong suspicion that the prickle/thorn botanic terminology post dates the Bard, however. And translation would also come into play when Roman historian Ammianus Marcellinus is quoted as saying "a rose among thorns" in the 4th century BC, although his rose plant could have been between thorny plants, rather than the rose flower being between spiky parts of the same plant. This saying is reputedly the origin of the phrase "a rose between two thorns", typically used by a third party when a lady is sitting with two men as a flattering compliment to her beauty. I have repurposed that phrase many times when I've been with two ladies, outrageously hinting that I'm the prettiest. But in the future should I say "a rose between two prickles"?
If I do I'll have to be very careful as it could easily come out all wrong...
Mrs H is not always - indeed it would be fair to say is rarely - fond of my instinct to cavil and nitpick at almost anything. One of my very favourite nitpicks dates back the best part of 35 years. We were watching Die Hard 2, the action thriller set at a snowbound airport which is the site of a dastardly plot by a bunch of baddies. Bruce Willis, playing off duty policeman John McClane, has - as in the first Die Hard film set in a skyscraper - again spent most of the film rolling around in his increasingly grubby vest fighting people after his concerns are ignored by the local on duty cops. In the denouement the baddies are escaping in a jumbo jet accelerating down the runway on take off. McClane, having been involved in a fight on the wing trying to prevent the plane taking off, has managed to open a fuel valve. Lying in the snow on the runway he uses his cigarette lighter to ignite the fuel trail. The flame catches the plane up and it explodes in a huge fireball.
As the titles rolled the conversation went something like:
Mrs H "well that was exciting - what did you think?"
Me: "Give me a minute, I'm doing some mental arithmetic".
Mrs H "eh?"
After which I pointed out that it wouldn't be possible to light kerosene with a lighter, it's just not volatile enough. If McClane had used a wick, just maybe, though probably not in the snow. When I'd done my maths I also pointed out that the flame speed of a hydrocarbon in air is at least an order of magnitude below that of a jumbo jet's take off speed.
So sorry Bruce/John, but the baddies got away.
I expect Mrs H told me that it was just a story, it was supposed to be entertainment and I should suspend belief when watching a film or reading a book.
Which is why I mainly read non-fiction. I'm just far too literal. And pleased with a top class nitpick!
But do I cavil, or nitpick? I may need to check if they really are synonyms...
Nerdy notes:
The flash point of a liquid is the lowest temperature at which it can form an ignitable vapour in air. For kerosene it's 38C, whereas for petrol it's minus 40C. Which is one of the reasons kerosene is used for jet fuel, it's very much safer. So McClane would have struggled to light a trail of liquid kerosene leaking from the plane in a sub zero ambient temperature. The flame speed of a hydrocarbon in air is typically around 4 metres per second (sadly I still remember this from working in safety and risk assessment). I was converting metres a second to miles an hour, so the sum I was doing would have been: 4 times 60 times 60 equals 14400 metres an hour; 1500 metres is a "metric" mile at the Olympics but a real mile is a bit longer (actually a bit over 1600). 14400 divided by 1600 is about 10. (The actual answer is closer to 9 but I would have been approximating). Clearly a jumbo jet take off speed is a lot more than 10mph (it's actually about 180mph). So sorry John, your flame couldn't catch up with the jet as it was just getting airborne, even if you'd been able to light it in the first place.
Expert nitpickers among you might counter that the flame speed I have quoted is for a laminar flame. Turbulent flow can significantly increase the flame speed, potentially up to hundreds of metres a second, which could certainly do the trick. However that requires confining structures to generate turbulence by interacting with the expanding combustion products. This is basically what happened at Flixborough in 1974 when a huge cloud of cyclohexane vapour mixed with air and didn't just catch fire but exploded with the force of a bomb. It was the largest ever chemical industry accident in the UK and it killed 28 people. The open air explosion created a supersonic blast wave, similar to high explosive in a rare and then little understood phenomenon called an unconfined vapour cloud explosion. On most occasions ignition of a flammable gas cloud results in what is known as a deflagration with the flame front travelling at less than the speed of sound. Deflagrations are extremely dangerous but they don't cause the type of damage typical of an explosion.
Subsequently it became understood that, for a vapour cloud to explode in this manner, the expanding gases have to be accelerated by interaction with structures - and the type of structures found on a chemical plant are capable of causing that as well as providing the ignition source for the the flammable mixture. The accelerating flame can then set off the bulk of the gas cloud in a hugely powerful explosion, not just a big fireball. But John McClane didn't have a large vapour cloud for the flame to accelerate through, nor any way of generating that kind of turbulence. The film just showed the flame catching up with the plane just after take off, resulting in it exploding in a fireball.
Unless the plane was taking off on a very hot day so a vapour cloud had formed and he ejected methane forcefully from his body, lit it with his lighter and used that to somehow set off a turbulent explosion. No, I'm not buying that bum story either but it wouldn't have been any taller.
Feeling prickly was the item that told me roses don't have thorns and it appeared in the New Scientist edition of 11 October 2025
"A rose garden filled with thorns" is a lyric is Taylor Swift's song Blank Space, apparently
