I though these were the same, but...

[Brunãozinho]

I have grown these two thinking they were the same, Parodia (Notocactus) horstii with different flower colors.
But then they started flowering, after more than a week trying to pollinate them, none had shown any signs of forming seed pods. So I figured out they should be separate species.

So, when searching for Parodia horstii images on the web, I found these two:

Parodia horstii picture from the erdikaktusz website:
Link: http://www.erdikaktusz.eoldal.hu/img/or ... r-1987.jpg" onclick="window.open(this.href);return false;

Parodia ottonis subsp. horstii picture from the erdikaktusz website:
Link: http://www.erdikaktusz.eoldal.hu/img/or ... r-1998.jpg" onclick="window.open(this.href);return false;

I think this is it, they look really similar to the plants in those images. I think I have a correct ID for them now, what do you think? Bellow are the pictures of my plants.

[DaveW]

Horstii was very variable as regards flower colours when it was first introduced in the 1960's as I recall and given a few different names. Notocactus purpureus is another of the group or same species depending if you are a splitter or lumper..

http://www.cactus-art.biz/schede/NOTOCA ... pureus.htm" onclick="window.open(this.href);return false;

Notocactus muegelianus was another name applied to it:-

http://www.alamy.com/stock-photo-BNBPXP ... rodia.html" onclick="window.open(this.href);return false;

http://kakt.info/galery/htmls/not_hor_m.htm" onclick="window.open(this.href);return false;

Take your pick Bruno, you can have what shade of purple, apricot or pink you want for forms of Notocactus horstii.

[Brunãozinho]

Yeah Dave, interesting nice colors for the same species!
those plants from the cactus art website seem a bit different also in the plant's body appearance.
I was hopping the two plants would pollinate each other and the offspring could have different flower colors. I'll keep trying with the paint brush.

[DaveW]

Interesting reading the article in Cactus Explorers 2 on Haageocereus by Aymeric de Barmon, referred to elsewhere, where he found that some clones of the same species would not cross pollinate but others would. Therefore it may just be the individual plant that will not cross pollinate rather than the species as a whole?

[Brunãozinho]

I have just read the article again. Do you mean self pollination Dave?
In the article he writes that a clone did not self pollinate but the other clone did, quite curious indeed.

The "parodia 2" is showing signs of fruit formation, I guess it's flowers were pollinated after all, but flowers kept opening for many days in a row. I thought flowers would not open anymore once they were pollinated, I wonder if that's true.

[DaveW]

Yes self pollination Bruno, but indicating that individuals of a species can have different pollination characteristics. Obviously being sterile in nature unless you propagate vegatatively is the quick road to extinction, therefore natural selection eventually weeds out such individual that cannot pass on their genes.

Dropped across these interesting articles, maybe it explains why stimulation with foreign pollen may induce self sterile plants to self with their own pollen?

https://news.brown.edu/articles/2012/05/flowers" onclick="window.open(this.href);return false;

http://www.amjbot.org/content/96/6/1159.full" onclick="window.open(this.href);return false;

http://www.amjbot.org/content/86/6/855.full" onclick="window.open(this.href);return false;

I suppose whether flowers open after pollination depends whether that first pollination was successful or not, then maybe the flower would continue opening if not until it was successfully pollinated or it came to the end of it's life unpolinated and did not set fruit. Although of course some fruits when set can contain sterile seed.

[Brunãozinho]

I find the topic on stimulation with foreign pollen really interesting, thanks for the links Dave, I'll save those texts and read them this weekend.

But I still don't get it why some flowers keep opening day after day even when you pollinate self-fertile species... My Notocactus haselbergii (should be self-fertile) kept flowers opening for a whole week, I used the paint brush every day and flowers kept opening... then they close and start setting fruit.

Just something to think about...could it be that the flower waits for cross pollination and if that doesn't occur, then it self pollinates?

[DaveW]

For selfing see:-

http://books.google.co.uk/books?id=UVGi ... ng&f=false" onclick="window.open(this.href);return false;

http://www.as.wvu.edu/~kgarbutt/QuantGe ... Plants.htm" onclick="window.open(this.href);return false;

http://www.growseed.org/selfersandcrossers.html" onclick="window.open(this.href);return false;

[Brunãozinho]

Again, thanks Dave. I saved those texts on my phone so I'll be reading them at parts, every now and then.