R. burmanicum

This species is found growing in the mountains of S.W. Burma at between 9,000-10,000 ft. The foliage slightly rounded, and medium in size.  The flowers are a nice light yellow, bell-like, with a good amount of fragrance. It only hardy to 15 F, so make sure you have the location for this one.  The flowers completely cover the plant every year in April-May.  Zone 9 - 10.