Haworthia dimorpha ( M.B.Bayer) Breuer(= Haworthia marumiana / archeri var dimorpha M.B. Bayer)- Mini article by Gerhard Marx.
Originally described as a variety of Haworthia archeri, this distinctive plant has recently been mingled up in erroneous and unfortunate synonymy with Haworthia marumiana. As mentioned in the discussion of Haworthia archeri, Haworthia marumiana is a spring-flowering and freely clustering species with numerous flower, fruit and leaf differences and restricted to vertical cliff faces in the wild and Haworthia marumiana is also a very easy plant in cultivation and proliferates to weed-like extent while Haworthia dimorpha, like Haworthia archeri, is rare and rather difficult to maintain and propagate. The association between Haworthia dimorpha and Haworthia archeri is quite close although the plants are easily and clearly distinguished. Haworthia dimorpha has fewer and wider leaves that are less densely decorated with teeth and mini windows. The initial name ‘dimorpha’ was derived from the drastic differences there are between wild plants and cultivated specimens of this element. In the wild the plants are small with closed rosettes and lighter green-brown in colour while in cultivation the plants double in size with more open rosettes and turn black-green to dark brown in colour. Haworthia dimorpha flowers during March.
The treatment of it as species Haworthia dimorpha under the Aggregate Archeri (See Haworthia archeri) by Ingo Breuer is sensible and welcomed. Haworthia dimorpha is a rare species restricted to steep south-facing boulders and almost solid sandstone slopes to the west and south of Constable Station, east of Touws River. It grows tightly wedged in rock crevices amongst lichens and is almost impossible to find when not in flower.