Haworthia hammeri Hayashi
By Gerhard Marx - 28 July 2023
To fully discuss this element would involve a book with as many pages as a short novel. That is because Haworthia hammeri displays links to several regional and named Haworthias like H. badia, H. mutica and H. maraisii. Interestingly and just to complicate matters further, in their 2012 species list Bayer and Manning lists H. hammeri as a hybrid “H. mutica X H. mirabilis”. The fact that H. hammeri occurs in several relatively uniform populations in a small area north-west of the Potberg raises the question whether one can refer to several cohesive populations as a natural hybrid occurrence. Bayer and Manning’s speculative assumption is based upon the fact that both H. maraisii , H. atrofusca and H. mutica occur very nearby, all within less than a few kilometres. The fact that H. mutica flowers during August-September and H. “mirabilis” var. maraisii flowers January-February weaken this conjecture somewhat but one can argue that the random plant does flower out of season occasionally.
However, if one does insist upon applying the hybrid theory it can only be accepted as an ancient occurrence when geographical arrangements were perhaps somewhat different. But then one must apply the same sceptical speculation to many other named Haworthia elements. It seems quite conceivable that many accepted varieties and species in Haworthia originated through some ancient hybridization.
Therefore, it seems implausible that a very recent hybridization could have produced such a stable and recognizable element as Haworthia hammeri and in such quantity as found in the wild.
Personally I have only visited three different populations of H. hammeri. One is a large population consisting of several hundred plants while the other two spots are small groups of only two dozen or less at each locality.
In the wild Haworthia hammeri can look like a small dull-coloured H. badia or even a form of H. mutica with somewhat acuminate leaves. In terms of flowers and flowering time it is therefore firmly rooted in the H. magnifica-mirabilis group. Bayer’s initial labelling as “H. mirabilis” in his Update 3 (Part 2) for these plants was therefore quite acceptable within his definition of H. mirabilis. H. maraisii grows very nearby and it is plausible that some interaction with H. hammeri has taken place as flowering coincides.
Another ‘mirabilis’ element growing quite close by is Haworthia joleneae. Some faint influence of the latter can also be detected in some plants of H. hammeri and both share the same microscopically rough skin texture.
Haworthia mutica also grows within less than 5 km from H. hammeri but as mentioned, flowering time for H. mutica is five months earlier than H. hammeri, so recent ‘hybridizing’ seems rather unlikely.
Some plants of H. hammeri develop in cultivation to look very similar to H. badia and can even be mistaken for it. H. hammeri can also occasionally have the blotchy lines and milky flecks in the windows as H. mutica but much more subtle and very infrequent. In addition it also has the fine shark-skin texture found in H. joleneae and also to some extent H. groenewaldii.
H. hammeri was discovered by Bruce and Daphne Bayer in 2005 during exploration of the general Potberg area. Their excellent field exploration and contribution to our knowledge of Haworthia distribution is of immense value and will probably remain unequalled.
Haworthia hammeri was named after the inimitable Steven Hammer who seems to have an endless range of amusing and flabbergasted reactions each time he is confronted with the name Haworthia hammeri.
