Here is a petite endemic species described by our colleagues Dieter and John in 2003. I have never seen anything of this plant other than the photos that John so courteously shared, but it looks distinctive to me.

I do not yet know what clade this species belongs to, but based on the protologue, I predict membership in Physiruellia.

Wild collected, Bolivia, Darwin Initiative Project #162/11/010; Photo by John Wood