the characteristic flower coloration has been shown to be an example of copigmentation, a result of the presence of malvin (an anthocyanin) and saponarin (a flavone glucoside) in the ratio 1:9. under the alkaline conditions (ph 7.9) found in the sap of the epidermal cells, this combination produced a pink pigmentation; the ph of the colorless inner floral tissue was found to be lower, at ph 5.6. experiments showed that saponarin produced a strong yellow colouring in slightly alkaline conditions, resulting in the greenish tone of the flower.