And if 'Baroni' the cultivar has been around for so long it may have selfed and dropped seeds of something that eventually looks similar to the species. That might account for height variations that may not provide conclusive ID of whether a plant is the species or hybrid that is being grown.

I imagine there may be select gardens that are confident they are growing the species?

Do you think the shade of yellow may be different? Or perhaps the nature of the scape, which Baroni describes as "slender" in his description of the hybrid? I am trying to discern if we can get any sense of what he saw as improvements of the hybrid over the species.

sooby said:Here's a description of the naming history of Hemerocallis citrina clipped from the American Horticultural Magazine of Spring 1968 (it's actually all about daylilies and downloadable as a PDF):

It is listed as "February" 1968 in the American Horticultural Society online publication archive. @ 236 pages it is booksized.

Read Schabell's article (DJ v47n02)

He mentions that Stout discovered that H. Citrina is self-incompatible. This is interesting, since Mueller recollected that the species originallly raised in Italy had been grown from seeds.

The reference to Kitchingman's quote is from an American Hemerocallis Society 1984 Species/Science Round Robin, but I couldn't spot that in the 1984 DJs published Robins

I wondered about the Kitchingman quote too but then I remembered that back then AHS had a number of paper Robins that circulated by snail mail, and I guess that quote didn't make it into the Journal Robin excerpts

You've collected an amazing body of research on the history of H. citrina and its early offspring Sue. We are grateful for your sharing it!

robinjoy said:You've collected an amazing body of research on the history of H. citrina and its early offspring Sue. We are grateful for your sharing it!

Yes, Thank you, Sue!

I want to add my thanks, Sue, as well. I should know but didn't that there's a treasure chest in the AHS archives! Thanks for pointing us in that direction.

robinjoy said:He mentions that Stout discovered that H. Citrina is self-incompatible. This is interesting, since Mueller recollected that the species originallly raised in Italy had been grown from seeds.

Yes, that is perfectly normal. The species H. citrina is self-incompatible. That means if you self-pollinate an individual plant that belongs to the species it will not successfully produce seeds. Every individual in the species (but not every individual in a clump) will be genetically different from every other individual (just like people (except for identical twins, triplets, etc.). So cross-pollinations between two different individuals of H. citrina will work and produce seeds. If seeds are collected from a natural population of H. citrina they will all have been produced by natural cross pollinations between genetically different individuals.

When I stopped to think about it, I knew that. Yet my mind completely applied the generalized self-incompatible meaning to the entire species instead of each individual plant. Weird.

@admmad Maurice, if you divide a clone of a self-incompatible daylily such as H. citrina then crossing between the two will presumably not work, at least initially. But if they were separated, say for example 50+ years ago, would you still expect the same result? I have a recollection from a plant propagation course years ago that over time even a vegetatively propagated clone can develop changes.

@sooby

if you divide a clone of a self-incompatible daylily such as H. citrina then crossing between the two will presumably not work, at least initially. But if they were separated, say for example 50+ years ago, would you still expect the same result? I have a recollection from a plant propagation course years ago that over time even a vegetatively propagated clone can develop changes.

Yes, Sue, if you were to separate two individual ramets (one fan of leaves, its portion of the crown and its associated roots) from a clump of H. citrina and grow them separately and repeatedly divide the two clumps down to single fans/ramets then over time somatic mutations would accumulate in each fan and the two fans would no longer be exactly identical genetically. However, there are probably about 25,000 to 40,000 different genes (plus an unknown number of other important sections of DNA) in each diploid daylily. We could not expect to have much more than one new mutation per generation or perhaps two generations. In 100 years we might expect 50 to 100 genetic differences between the two. Unfortunately most of those differences would probably be effectively "silent". That is, if we sequenced the DNA we could see the differences but if we sequenced the proteins made by the mutant DNA we would not see any differences at all quite often and at least some of the rest of the time we would see a difference but it would not be of any consequence. A proportion of the genetic differences would have visible effects. It is possible that some of those genetic differences might affect the self-incompatibility. However there are other aspects of the self-incompatibility of daylilies that would probably have stronger effects.

Stout indicated that some of the daylilies that he examined had what might be considered a typical genetic self-incompatibility system. But others had what might be considered a primitive type of self-incompatibility. In that form, an incompatible pollination appears initially to have been successful. Only after a few days is the apparently developing pod aborted (late-acting self-incompatibility system). That is similar to what happens sometimes when daylilies of two different ploidies are crossed. The exact mechanism(s) that might be involved in such primitive self-incompatibility is not yet known. It may be that such mechanisms are strongly affected by environmental factors or that they may be intrinsically unstable. In any case it is possible that incompatible pollinations may sometimes/rarely "escape" or "avoid" the incompatibility and produce one or more seeds. Perhaps daylilies may sometimes have a form of "pseudo self-compatibility".

Stout also found that incompatibility between two daylilies may only be one way. That is A x B fails but B x A works. Incompatibility between two particular different daylily individuals is a potential consequence of self-incompatibility.

Fascinating explanation, as yours always are Maurice!

What constitutes an "individual"? It sounds as though it doesn't even have to be a distinct crown with associated fans. You mentioned distinct individuals could coexist in the same clump,.

That is what I thought also, and the more I thought the more confused I became. I was pretty confused to start with.

@robinjoy @seedfork
If we think of an individual as being a single living entity then a daylily ramet is an individual. A ramet being one fan of leaves, a piece of crown and some roots that is completely separate from any another fans of leaves with their pieces of crown and roots. Note that the use of fans here is for the leaves.
So if a clump of a daylily cultivar was divided into individual ramets then each ramet would be an individual.
If the clump is relatively young and therefore small, each individual ramet ("fan" as per the AHS dictionary definition) would perhaps be 99.9999999% etc. genetically identical to each other ramet. However, if the clump is very old (say 100 years old) and we have a second clump that is also 100 years old and we compare one ramet from each clump to each other then the two ramets might be only 99.8% genetically identical.

If I take a clump of a daylily cultivar and divide it into single ramets and replant them then each ramet is an individual. The ramets will be different sizes. They will be different ages. Some may have flowered and others may not have flowered. Some may have grown in patches of soil with fertilizer; others may not have had as much fertilizer. Their histories (the environments they had experienced) will be different. There will be differences between ramets. Some of the differences may be larger and more important and may last longer than others. The differences will depend on the exact environments (probably down to minute differences) that each ramet had experienced. Part of those potential differences is that they may not be exactly 100.00000% genetically identical. All the differences, both environmental and genetic depend on time - the amount of time that the ramets have experienced since they developed.

Maurice-
Is it necessary for the clumps to actually be divided to create these separate individuals, or is it conceivable that ramets on opposite sides of an old clump could be genetically different?

Also, given the assumption that separate clumps can develop different genetics over time, should we expect this is also happening with modern hybrids? Especially those that have been around for many years?

@robinjoy

Is it necessary for the clumps to actually be divided to create these separate individuals, or is it conceivable that ramets on opposite sides of an old clump could be genetically different?

It is not necessary for the clumps to have been divided and separate for a long period of time. Ramets on opposite sides of an old clump could be genetically different. The qualifier with making the statement about genetic differences between ramets in one clump is that although the distance between any two ramets is a reasonable measure for how long any two ramets may have been separated it will not be a perfect measure. That would be a problem especially with daylilies that produce new fans on long rhizomes.

Also, given the assumption that separate clumps can develop different genetics over time, should we expect this is also happening with modern hybrids? Especially those that have been around for many years?

Absolutely, although the age difference between ramets of modern hybrids would on average be smaller and therefore any genetic differences that have accumulated would be fewer.

I am going to emphasize that the genetic differences that may have accumulated between ramets of the same cultivar over very long periods of time are not likely to have noticeable effects when compared with the differences between ramets that can be caused by simple environmental differences even in the same garden. Occasionally they will have large visible effects - called "sports". In other plant species there are certain cultivars that have been identified as unusually prone to producing sports. They still will be quite rare. I do not know of any daylily cultivar that is similar.