Pelargonium patulum white petals

This white Pelargonium patulum flower has dark purple blotches on its upper petals above a pattern of various line and dot markings. The five-branched purple stigma on the paler style in the photo is small but ready for receiving pollen.

Behind the petals the five pointed sepals of the calyx appear star-like. Pelargonium flowers have one sepal, the posterior one behind the upper petals that deviates in structure from the other four. It houses the nectary tube or hypanthium where it joins the pedicel (Manning, 2007; iSpot; Wikipedia).