"I am just curious by Donalds portulaca. That pretty specimen have leaves which seem to be intermediate of umbraitcola and grandiflora. Is it possible as the hybrid of them ?"
I suppose it's possible. Since it arrived with the Bougainvillea, it was probably something that was being cultivated at the place of origin. I think at least it would be an improved variety of some sort. The blooms are large and colorful.
On my attempt at overwintering Purslane and Portulaca, this one overwinters quite well and is still growing in the same blue cooking utensil in the photo. What was in with Bougainvillea I ripped out when I repotted the Boug. Now there are many plants of it up from seed. If it's a hybrid, then maybe those seedlings will tell us. Maybe not. They haven't bloomed yet.
The other plants which are sold commonly as 'Moss Rose' and I call Portulaca did not overwinter. Even some that I managed to get through 'til spring continued to decline. Maybe using a greenhouse and continually taking cuttings to propagate a plant would work. Those containers where I was trying to overwinter them have also produced a lot of seed grown plants. Maybe enough will resemble the selected parents that I'll be happy with them. Time will tell. It's been a cool spring and only a single plant of those has bloomed. It did match what I was trying to overwinter.