Thank you Marilyn and Julia.
'Astrid' is one of my favorite semps because of the unusual color and almost curly cilia along the leave margins.

Crests are formed when the meristem (growing tip of the plant, in semps it would be the tissue at the center of the rosette) is normally DOME shaped. This allows for a symmetry of the plant as leaf primordia arise from the dome in an orderly position creating a symmetrical rosette. When the meristem expands to a LINE now the leaves arise from points along the line, forming a crest instead of a normal rosette.

Some cultivars are more prone to this. Fuzzy Wuzzy is the champ at this and it's pod parent Denise's Cobweb forms them often too. However I have never seen them on Hot Shot or Devil's Advocate, that are its sister seedlings. Butterbur is a non-cobweb that forms them often too. The one on Dark Cloud last year was 9" across. Just amazing!

The genetics of it is rather poorly understood. It is considered a teratological form. Some consider it is a virus although I have seen no instance where it has been transferred to another cultivar.

Kevin

JungleShadows said:Crests are formed when the meristem (growing tip of the plant, in semps it would be the tissue at the center of the rosette) is normally DOME shaped. This allows for a symmetry of the plant as leaf primordia arise from the dome in an orderly position creating a symmetrical rosette. When the meristem expands to a LINE now the leaves arise from points along the line, forming a crest instead of a normal rosette.
Kevin

Sorry, I am confused, Kevin?...You say "crests are formed when meristem...is normally dome shaped." but then you say, "When the meristem expands to a line...forming a crest". Does that mean that cresting involves both growth from dome shaped meristem and then expansion of meristem to a line to result in the cresting?...meaning it is a 2 stage process?

Bev,

Thanks for catching that! I type with one finger and sometimes the brain and the fingers don't get it together.

So, a NORMAL rosette has a DOME shaped meristem and when the meristem converts to a LINE you get a crest. In the picture of Astrid crest that Lynn showed you can see the line quite distinctly!

Kevin

So we do not really understand what causes this to happen?
But we do know that some cultivars are more prone to doing this.

Just wanted to add that crested semps can be propagated by division like normal ones, so there is no reason to lose them. I do not know if there is a "genetic" or programmed limit to how long you can propagate them this way, but had one that lasted 3 years and used it to produce additional plants before losing them all last year (bad weather for their new location)

Also, it seems that some of the "line" types will zig-zag while others will maintain the line and end up curving in on themselves over time. By that I mean that some zig-zag flat across the ground while others will grow out and down around, almost in a spiral or corkscrew.

Do you have some photos you can share with us twit? I know I have seen some of your in the past, but I don't remember which variety/cultivar they were.

Photo update on my crested S. tectorum from Costigliole, Piemonte Mts, Italy. It is producing normal offsets.

That is really nice!

Great that it is producing.

I am thinking I need to remove the normal offsets that are growing from it.

Why?

Opinions differ as to what causes monstrose or crested forms. 'Weirdo' and 'Fuzzy Wuzzy' were strange from day one but of course others are sports of normally-formed cultivars.

Just gathered seed off the a crested 'Dark Cloud' to se if anything crests in the seedlings.

Kevin

Interesting thoughts Kevin.

I will take the normal offsets off of the crested rosette, so they don't over power the less vigorous crested rosette.

I like the way the mix looks, though Lynn. I think the "normal" rosettes show off their crested seedlings (and vice versa, to some extent). But if you are raising them primarily to propagate for sale, then that is something different. MR

No, not raising it for sale. It is just an offset from a normal rosette. May have ended up this way do to some kind of damage when very young?

Crested Whirligig or maybe that's just how this one is

Definitely looks like something's going on...or is it just twins, triplets???

Once I posted the photo I saw that all of them are clumping like that, which seems different than an actual crest, but it is still cool looking so - I posted!

Glad you did, Greg!