Book  (Oct 2001)  Page(s) 299-300.  Includes photo(s).

Book  (1965)  Page(s) 441.  
 
6. Clematis obvallata (Ohwi) Tamura. C. japonica var. obvallata Ohwi; C. japonica forma obvallata (Ohwi) Ohwi -  Kōya-hanshōzuru. Closely resembles the preceding [C. japonica]; bracts at the top of the peduncles, larger, often colored and involucrelike. - Mountains; Honshu (s. Kinki Distr.), Shikoku.
Var. shikokiana Tamura. Shikoku-hanshōzuru. Bracts smaller. Shikoku.