Var. chlorophyllum has been described as a plant with no anthocyanin (red pigment) in the leaves and a normal coloured flower (i.e. coloured like the typical form). Others find that this isn't sufficient for the plant to warrant varietal status, and subsumes it under the typical variety. Olaf Gruss et al. see it as a colour form, fma. chlorophyllum, which to me seems the most appropriate designation!