Dryas octopetala

[Hoy]

I can't say whether they're hybrids or not but the mulipetalled form is highly uncommon - in fact I have never seen any with much more than 8! So probably they are hybrids?
The form of the petals differ, however, as shown here: (Dryas octopetala)

[cohan]

I think at the time I took those photos I wasn't even thinking about the two species and the possibility of hybrids, so I didn't take the kind of photographs that would highlight the important characters - maybe another time!
Here's another shot from a different site- very different kind of habitat! Lower in elevation, below the treeline though still not by a lot; This plant is in a wooded area, on nearly bare rock next to a stream/waterfall..  It's just behind a popular roadside stop where you can look back on the highway where it has just climbed up/down from the river valley below to near the treeline... We stopped there this year at the end of May, and this shaded area still had some deep snow banks...

[Weiser]

I can keep D. octopetala alive and spreading in Reno as long as it gets watered regularly. It seems to take the heat pretty well in that the year old leaves shrivel and dry while the new leaves stay nice. I never get many flowers however maybe four or five on a one foot square mat.

Do you think that I don't get cold enough in the winter to set buds?

[Hoy]

I have grown it (or maybe it was the cross x sundermannii) at home where it flowered every spring and my winters are not cold. I have also seen beautiful colonies at the sea level in southern Norway (in northern Norway all kind of alpines grow down to sea level). The plants in south don't get too much cold (they are relicts from the last glaciation and are far from the mountains).

[cohan]

Can't help with that, John- I haven't grown it yet myself, and of course when I do, it won't have any problem with lack of cold!
I do also wonder, though, if there is simply variability in number of flowers per plant? Some of those I photographed had quite  a few flowers, others not so many.. I haven't seen enough of them in different places in flower to really know, though...