Is this dichotomous growth on my Lobivia aurea v leucomalla

[WayneByerly]

I've got a Mammillaria karwinskiana that is undergoing dichotomous growth ... and it is the root cause of my even learning the term. And now I've got a Lobivia aurea v leucomalla that is beginning to look like what caused me to ask what my M. karwinskiana was up to. The dish shaped depression in the top of the cactus is no longer round ... it's oval.

So ... dichotomous growth is what it looks like to me ... but does it look like that to anybody else? So I'm soliciting your opinions ... does anybody have an opinion about this cactus and it's crowns shape? Does anyone else think that this the beginning of dichotomous growth?

This is what it looks like now (May 2018)...

20 Lobivia aurea v leucomalla (dichotomous growth).jpg (114.78 KiB) Viewed 1762 times

...and this is what it looked like then (Dec of 2017).

2017-12-28 DSCF3231 800x600.jpg (109.37 KiB) Viewed 1761 times

[greenknight]

Maybe, or it may be going cristate. Just have to wait and see.

[WayneByerly]

Now THAT (going cristate) would be interesting... I cant wait to find out exactly what it is doing. I guess it will take a year or more to find out though.

[WayneByerly]

BTW... I don't think I've ever heard any information at all about what makes a cactus go cristate. Does anybody know?

[DesertSun]

BTW... I don't think I've ever heard any information at all about what makes a cactus go cristate. Does anybody know?

I have read that it can be due to the cactus being traumatized by some reason.
Another thing I read is that it can be caused by a virus. But I'm not sure if this causes both cristate forms/or fasciation.

[DaveW]

Too early to be sure it is either going cristate, dichotomous or simply staying normal. Plant could also be a Matucana rather than a Lobivia, flower would decide. It's always hard to be sure of genera from photo's without flowers since the spination on some genera can look very similar to others.

http://www.cactus-art.biz/schede/MATUCA ... rplexa.htm

https://kaktusy-sukulenty-behul.webnode ... r-116-jpg/

As to what causes fasciation, be it either cristation or monstrosity, nobody really is sure since there could be a number of reasons why the growing point is affected, or why monstrose growths proliferate on a cactus:-

https://mycotopia.net/topic/62972-what- ... te-growth/

http://www.cactus-art.biz/note-book/Dic ... tation.htm

[cactushobbyman]

My Lobivia was growing normal and then started to look funny at the growth tip. It continue until it was clear that it was cresting. So, I decided to cut off the crested top and root it. I haven't found this year's picture but the crested has doubled in size and the original plant has sent out offsets. One of the offsets is starting to look funny, could it be cresting again? Now that you have posted this topic, I am going to have a better look.

a.jpg (46.75 KiB) Viewed 1671 times

[WayneByerly]

... Plant could also be a Matucana rather than a Lobivia, flower would decide.

No, NOT a Matucana. Here's the flower.

047.09 2017-04-15 DSCF7672.JPG (80.79 KiB) Viewed 1663 times

047.12 2017-04-17 DSCF7678.JPG (95.02 KiB) Viewed 1663 times

[DaveW]

No definitely a Lobivia Wayne. The crinifera Matucana's look very similar in spination and leucomalla is itself variable as with many of the L. aurea varieties, which illustrates how a flower helps with identification.

http://llifle.com/Encyclopedia/CACTI/Fa ... leucomalla

[WayneByerly]

... which illustrates how a flower helps with identification.

Odd isn't it how that one single aspect of a cacti's attributes can be so definitive in its ability to identify a species? I would think it would be some combination of attributes like number of ribs + spination + shape that would do the trick. Isn't that logical? But no... It's the flower... How very peculiar.

Well ... as always, one can always depend on you to provide very specific, detailed and useful information to us Noobs here at the Forum. You are greatly appreciated DaveW... thank you very much for the links.

[ElieEstephane]

For more accurate approach with very similar species of the same genus, people look at seed morphology (size, shape, color) and many other characteristics like milky/watery sap in mammillarias...

[WayneByerly]

My Lobivia was growing normal and then started to look funny at the growth tip. It continue until it was clear that it was cresting. So, I decided to cut off the crested top and root it...

Ooooooohhhh... could you post MORE pictures of it please? I for one would be delighted to see more pictures of it.

[WayneByerly]

For more accurate approach with very similar species of the same genus, people look at seed morphology...

Oh yes, I forgot about the seeds... Is it really more accurate than what the flowers provide?

Thanks Elie... I appreciate your time and input...

[DaveW]

Linnaeus, "the farther of taxonomy", originally classified plants on the flowers. In fact in his original work he classified them on how many stamens the flower had. It was thought at the time, due to it's fleeting nature compared to the plant body itself, the flower would have changed less due to ev0lution. Now of course we know it can be just as prone to ev0lve due to different pollinators etc, even within the same genus.

You can of course classify things using any features you like, however we now tend to prefer monophyletic classifications where everything in a genus has ev0lved from a common ancestor, or what we believe to be so, which is why DNA (plant chemistry) is often upsetting previous classifications based on morphology (how the plant looks) since plants growing in similar habitats, even from different ev0lutinary lines, have often grown to look like each other.

https://en.wikipedia.org/wiki/Linnaean_taxonomy

[WayneByerly]

Form follows function... A refrigerator will always look like a refrigerator, and there's a good reason an airplane looks the way it does.