Claim: Knowltonia vesicatoria (of the Ranunculaceae a.k.a. buttercup or crowfoot family) is one of at least ten species of Knowltonia that are native to South Africa, which can be differentiated from the other species by looking at its leaves and stems being hairless and slightly jagged, toothed margins of the leaves.
Evidence: Knowltonia vesicatoria (Brandblaar) is an attractive, shade-loving plant of the family Ranunculaceae, that is indigenous to the southern parts of South Africa. Ranunculaceae (buttercup or crowfoot family; Latin rānunculus "little frog", from rāna "frog") is a family of over 2,000 known species of flowering plants in 43 genera, distributed worldwide. This is one of at least ten species of Knowltonia that are native to South Africa. Knowltonia vesicatoria can be told apart from the other species by its leaves and stems being hairless, and by the slightly jagged, toothed margins of the leaves.