Book  (Oct 2001)  Page(s) 136-137.  Includes photo(s).
 
Clematis brevicaudata
Origin: China, North Korea, Mongolia, Russia
Species 1818
... single, scented, small flowers... four or five narrow, non-overlapping tepals, which are creamy white, flushed with green or yellow... The stamens consist of cream filaments and yellow anthers...