The phenomena is called 'fasciation'. If I understand this correctly, fasciated stems occur when multiple buds fuse together and form a flattened stem structure. It is a somatic event (in vegetative cells), not a genetic mutation that will be inherited through seeds. Has anyone over collected seeds to see if resulting plants also fasciate? Do any of you have photos of plant fasciation?
Some families of plants are more prone to fasciation than others (Asteraceae comes to mind for one), so you might grow seeds from one and find that it exhibits fasciation from time to time just because of that. I don't think you'd ever end up with a situation where a plant only produces fasciated blooms either--even on plants that are prone to it you'll still get normal blooms too. So to me it's not like a variegated mutation that you can propagate and produce plants that will always exhibit that characteristic.
I think I have some pics of a fasciated Gerber daisy from a few years ago--I'll have to look for them later and I'll post them if I can find them.
More pictures of would be fun to see. I'm curious if this type of group pattern ever occurs in trees. I've never seen an example of a tree. Search around the web after learn about my buttercup, I saw many daisies, lilies and cacti, never a deciduous or evergreen tree.
I was looking through some old photos and one of them reminded me of your thread. This is Sidalcea oregana growing in the Santa Rosa Mountains north of Winnemucca, Nevada. It caught my eye as we were driving by. I bet it was really spectacular a couple of weeks later when more of the flowers opened.
About three years ago I had a lily with a fasciated stem. When it came up the following summer it was a single stem as it was last year as well. I have the feeling that an outside force caused the fasciation.
Fasciation is just something that happens sometimes--some species of plants are more prone to it than others but it's not something you'll be able to reliably reproduce by growing seeds from a plant that did it (or even by asexual propagation like cuttings)
'Cathy166' said: "I have the feeling that an outside force caused the fasciation."
I have volunteer sunflowers every year. Last year I began utilizing 'Liquid Gold' in my yard, and one of the first plants I tried it on was a bush sunflower. Well... it not only got deeper green leaves & grew healthier, but it soon put out flowers that were fused together. I think it was because the nitrogen in the 'L.G.' caused the buds to mature too fast, as there is normally some 'branchleting' & then a single bud/flower on each branchlet... But, in these cases no 'branchleting' occured, and the single flower produced appeared to be one of several fused flowers & mis-shapen. None of the other sunflowers did that, just a few that I poured 'L.G.' under. I stopped using the L.G. on it, and I think that it eventually had normal flowers. So...
So, I am wondering how many fasciated plant parts might be caused by excess nitrogen from some source...
(Or, is what I've described something other than 'fasciation'...?)
Fused together flowers do sound like fasciation. I don't know if excess nitrogen encourages it or not, but it's certainly not necessary. I never fertilize my flowerbeds and I've had fasciated Gerbera daisies.
I found this information on the Royal Horticultural Society website:
Fasciation may be caused by:
Random genetic mutation or disruption.
The bacterium Rhodococcus fascians.
Damage to the plants by frost, animals (including insects), chemical or mechanical injury – even hoeing or forking around the plant have been implicated.
I don't know if your fertilizer was to blame--quite a few plants in the Asteraceae family (which sunflowers are a part of) are prone to fasciation via the random genetic mutation/disruption mechanism so even if you don't fertilize, disturb roots, etc they can still develop fasciated flowers.