Mutant (fasciated) dandelions

I dug a half-bushel-basketful (of normal dandelions) from our front yard yesterday, but have never seen any like the one shown here.  One possible explanation:

I've seen those before, in Alberta. I'd always assumed they were excessively polyploid. Dandelions reproduce through parthenogenesis, which makes them more likely to develop polyploid types. Most plants can tolerate being quadruploid or even hexaploid, and survive nicely. In fact, modern wheat is hexaploid, hence the high yeild; polyploid plants tend to develop much larger flowers and fruiting bodies.

However, from current research it would seem to be a type of deformity called fasciation in which a normally spherical growth part is distorted and instead grows into a fan shape. This results in flattened, broad stems and can result in multiple flowers growing on one head.

However, your sample seems to have a mostly round stem. And the fact that it has other stems nested inside it is curious. When plants end up having too many sets of chromosomes to survive, one symptom is multiplication of functional parts. I suspect that what you have there is, indeed, a dandelion plant that has one too many jewels in the family trunk.

I'd do a karyotype on that shit. This might not be possible with a dead sample, but then again, if you take enough samples from it and stain them all you'll inevitably find at least one cell that was undergoing mitosis when the plant died. There's got to be a way to find out how many sets of chromosomes that sucker had. I'm very curious.

More pix here.  And a video here.