Austrocacti

[edds]

There might not be an advantage to it Ralph.

As long as a mutation isn't severe enough to hamper reproduction it doesn't have to be a positive to stay in a population or even spread! Neutral mutations can collect quite happily in all genomes, it's only when they are sufficiently negative to hinder successful reproduction that they might be selected against.

[ralphrmartin]

On the other hand, even something that only confers a 1% advantage can spread through a population in a short time (a few hundred generations if I remember right). That might be a few hundred years, a geologically insignificant time. Of course, many cacti have (locally) quite small populations, making it easier for chance mutations to get established.

[edds]

On the other hand, even something that only confers a 1% advantage can spread through a population in a short time (a few hundred generations if I remember right). That might be a few hundred years, a geologically insignificant time. Of course, many cacti have (locally) quite small populations, making it easier for chance mutations to get established.

It can be even more rapid. It's is hard to quantify an advantage (or disadvantage) when a gene never works in isolation and it is the organism selected for at the level of the individual. But yes, small positive effects can cause rapid spread if the organism has a short generation time and a high individual fecundity with high predation or other selective factors.

To me the mutation you showed looks like a developmental issue as those petals can become anthers in that arrangement to create a more double flower. In fact with the structure of most cacti flowers I'm amazed fully double flowers aren't more common.

[Kees]

This plant: Ausotrcactus subandinus SAR6842/4 has very unusual petals. Inside there is a structure which might be a few infertile stamens fused to the petal - anyway, the result is like a little spearhead on the inside of each petal, giving the flower a strange appearance. Can anyone suggest what the purpose of this might be? To help trap insects inside the flower for a better chance of pollination?

sa.jpg

It may be an evolutionary thing: petals evolved from stamens, maybe evolution got stuck somewhere halfway.
If you look at "flore pleno flowers" (is this a proper English term?) you will see a similar thing: e.g. petals with an anther. In this hemerocallus you can see 3 of such petals with an anther.

[ralphrmartin]

Thanks Kees, yes, similar development. Yes, we call them flore pleno in English.

[ralphrmartin]

Super new spines on this Austrocactus pauxillus SAR8283/2:

[ralphrmartin]

One more in flower: Austrocactus sp. HS52. This time the flower is much paler than the one it produced in April.

[ralphrmartin]

And now for a question. Does anyone know whether Austrocacti are self fertile? My A. bertinii has produced several seed pods, with plenty of seed.

[Tony R]

And now for a question. Does anyone know whether Austrocacti are self fertile? My A. bertinii has produced several seed pods, with plenty of seed.

Norbert (Nobby) and Elisabeth would.

[nobby]

It's an old discussion between Herman Vertongen and myself. He says some are self-fertile and I say they can be partially stimulated by stimulus pollination. (I hope you can understand what I mean, in German we call it "Reizbestäubung".)
I believe that without external stimulation, nothing happens. But we only believe - we don't know!
Nobby