New plants at this week's Chelsea Flower Show
Surprise trilliums

A spectacular new/old foxglove

DigitalisMD080520+057 Over on the Cool Plants blog from Ontario Canada, Mark Denee has posted about this amazing foxglove that turned up in a batch of ‘Excelsior Hybrids’.

This is an especially impressive example of a form which has been seen occasionally since at least the 1800s. It’s usually represented by what is now called Gloxinioides Group and in this form the spikes are topped by one huge flower the shape of a gloxinia flower. Sometimes this flower is double, and is then sometimes referred to as ‘Monstrosa’ – the names of these, given in Victorian times, have become a little confused and over the years slightly different version turn up under a range of names.

This form in which the flower seems shredded into slender threads is rarely seen and reminiscent of the pure white ‘Anne Redetsky’ and the spotted white ‘Saltwood Summer’ in which every flower on the spike is split into five segments.DigitalisSaltwoodGJR6937-400

It should be possible to fix this startling yellow foxglove so that seed comes reasonably true… first, isolate it from all the others! Then sow all its seed and grow the plants in isolation from other foxgloves – then pull up and discard all but those which retain this dramatic feature. And keep this up until they come true. Might take a few years, though.

Comments

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Mike Grant

When I worked as a botanist at RHS Wisley we would get 5 or 6 of these funny foxgloves sent in every year. It is a condition we called terminal peloria, which sounds like a fatal disease!

True peloria is where a normally asymmetric flower, such as a snapdragon, develops in a symmetric manner and becomes tubular rather than two-lipped. The condition in the foxglove is more complex as the abnormal flower not only has more than the usual number of parts, resulting in a large cup-shaped flower, but it also terminates the flower spike. You will also notice that the repeated elements are the lower parts of the normal flower tube with the spots on, rather than the unspotted upper parts, this always seems to be the case.

The reason for the condition is not known but is likely to be a genetic disturbance. Researchers into flower development at the John Innes Centre, UK, have discovered a gene in snapdragons called centroradialis that controls the extension of the flower spike. It may be that a mutation in a similar gene in foxgloves inhibits extension of the flower spike, thereby leading to an abnormal terminal flower. The JIC discovery is interesting from an evolutionary point of view as it is thought that, in early plants, non-extending inflorescences, such as in buttercups, were the norm. It is suspected that later plants evolved the ability to switch off the terminal flower and thereby grow longer and more productive flower spikes.

If you sow seed from these foxgloves, even from the normal flowers, a proportion of the resulting plants may show the same characteristic. As Graham says, seed companies have sold seeds of similar foxgloves under such names as ‘Campanulata’, 'Gloxinioides' and ‘Monstrosa’, and this may explain why the condition is more often reported from gardens than the wild.

Graham Rice

Thanks Mike - I was cautious about getting into all this but you explain it well. I hope Mark Denee will sow seed from this plant and take some pictures of the resulting plants.

Mark Denee

Mike - thanks for the more technical explanation. Googling "peloric Digitalis" provides for some interesting reading. One from jstor.org referred specifically to a 1907 experiment at Reading in regards to peloria inheritance in Digitalis.

In any case, I believe I will attempt to isolate this form and collect seed -- even if it just for the fun of it...

Graham Rice

Mark - when they flower, please post pictures of the first batch of plants grown from this foxglove on your blog. Thanks!

sandy

Wow! I love foxgloves and these are just stunning!

Graham Rice

Yes, sandy, there are so many different foxgloves and almost any of them would improve most gardens.

Snowman 54

Ah ha ... when the first plant did this, I thought it was due to physical damage and the double flower was nature's way of trying to make the best of a bad deal. When a second plant did it, my assessment of damage being responsible dropped dramatically: when a sub-lateral also did this, I thought it had to be genetic.

Thanks for the excellent addition to this blog Mike. My thought is that this is a recessive gene and not on the chromosome that determines colour, as A) it "appeared out of no where" from self seeded plants and B) I have one each with white and purple petals. These flowers have 13 stamina ... good old Fibonacci ... and with a large bell shape made of just one petal, but with the edges being a number lips. I am collecting the seeds from these two plants, keeping them separate of course.

If anybody wants seeds, please contact me via http://www.ahead-designs.com/digitalis_peloria.html

Steve

I was taking picture of foxgloves in a wild garden just the other day and ran across one of these 'terminal peloria'.
I took three pictures which I'll post on my blog.
http://steveallatphotospeak.blogspot.com/

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