The long peduncles (10-30 cm) elevating the flowers well above the leaves are unique to Clematis baldwinii among the simple-leaved species of Clematis subg. Viorna in the flora. Broad-leaved, large-flowered plants have been segregated as C. baldwinii var. latiuscula , but many intermediates connect the extremes, and flower size is not well correlated with leaf shape. As noted by C. S. Keener (1975), leaf shape appears to be uncorrelated with distribution; collections from a single population often include broad- and narrow-leaved plants.