Dark purple legume, very dwarf, in Sikkim

[Claire Cockcroft]

I photographed this dark purple pea above 4900m in Sikkim.  With the two lower petals separated, it doesn't match any description in Polunin & Stainton.  When I first glanced at it, I thought it was a viola, but the leave are definitely not viola leaves.

Can anyone suggest a name?  Thank you.

[Dionysia]

Looks like Gueldenstaedtia himalaica to me. Lovely plant.

[Claire Cockcroft]

Thank you so much.  I've been puzzling over it for quite a while.  Your ID looks spot on.
...Claire