Pelorism - what is it and why is it so prevalent this year?
Pelorism and pseudopelorism are weird genetic mutations that affect orchids and other plants.
Rather than my offering a clunky description, I will refer you firstly to the Wikipedia entry for the term: https://en.wikipedia.org/wiki/Pelorism
There are two types of pelorism:
- Type a is where the lateral petals, normally plain-looking affairs, take the form of extra labellae, or lips, so an orchid flower looks like it has three lips and three "normal" sepals. These are probably the types that gave rise to the word; The terms comes from the Latin and Greek words for "monstrous"
- Type b is the opposite to type a, in a sense - it is where the lip is replaced by a normal petal, so the flower looks like it has three sepals and three petals...much less monstrous and rather plain.
- Pseudopelorism is more common than either of the above mutations: this is where all six parts of the flower, 3 petals and 3 sepals, look similar - like the example above - a pseudopeloric Common Spotted Orchid at Folkestone, Kent earlier this year, found by Stu Keeler.
The reason I post this as a second subject for this blog is that whilst previously I had seen very few examples of any of these orchids, in 2024 I have seen no fewer than four species exhibiting these types of mutation in person, and have seen photographs of others. Interestingly, and surely co-incidentally, this includes ALL THREE species of UK Fragrant Orchids!!
The strangest of these was no fewer than three examples of Coralroot Orchid found in close proximity to each other in the Highlands of Scotland at the end of June by Elinor Smith.
These showed type a. pelorism, with three identical lips all in a triangle, giving the plants a curious likeness to tiny Irises. Photos below of these wonderful beasties:
These plants followed pseudopeloric Chalk Fragrant Orchids in Worcestershire, found by Glen Dipple (bottom), and a Heath Fragrant in the Elan Valley, Powys (Top) found while searching the wonderful meadows of the inspirational wildlife-friendly farmer Sorcha Lewis, both earlier in June
Then, only last week my friend David Farrell from Co. Roscommon in Ireland sent me this photo that trumped both of my examples - a pseudopeloric Marsh Fragrant from the west of Ireland, found by his observant wife, Frances.. This multicoloured beauty wins the Freaky Fragrant award for 2024, for sure! They will be publishing details on their website soon...www.wildwest.ie
This post is à propos nothing, really - the origins of pelorism are speculative but probably genetic, but why so many seem to have appeared suddenly this year is a complete mystery to me, so I can't answer the second question in the title! Any suggestions are therefore welcomed in the comments!
One thing is for sure for this type of mutant - they look so strange that they can often be misidentified as hybrids or even something else. Butterfly Orchids have particularly suffered in the past for having been identified as hybrids between them and Small White Orchid. Hopefully this post will alert the reader to what these strange orchids can look like and enable correct identifications. My recommendation is to look at what else is around and go for that as your option, if the identity is not immediately obvious.
You can find more details in the 1985 "Watsonia" paper by Professor Richard Bateman here:
https://www.researchgate.net/publication/259176605_Peloria_and_pseudopeloria_in_British_orchids
There is a more scientific and in-depth paper by Richard Bateman and Paula Rudall here:
I expect it could always be a number of factors that cause it. The colony of Pseudopeloric O. mascula I discovered is exactly that - an entire colony of about 15+ plants together in an area, but also alongside more 'normal' ones. My theory is that they are all F1 seed set from the same parent pair, rather than an environmental stress or similar factor. I like to believe it was from an O. mascula x O. purpurea crossing that set seed, causing mutations but still viable enough to grow to mature plants. Of course an outlandish claim like this would never be proved/disproved without in-depth genetic assesment.
ReplyDeleteAgreed, that group must have inherited identical genetic mutation
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