Just what do we do with names for Haworthia?

Previously published in BCSJl (Cactus World) 30.4:211(2012)
M B Bayer

Taxonomy always provokes differing views, and Haworthia in particular has been subject to years of vacillation. The author has long been a campaigner against the haphazard proliferation of new names for every new, morphologically different population or variant. He questions the vagueness of a conventional species concept and pleads for a more reason-based, logical and sensible, communal approach to understanding and classifying Haworthia species. He hopes in this article to convey a message which is relevant to whatever genera of plants you grow. Photography by the author.

In Haworthia, professional botanists have struggled with and avoided the group because it is so infused with amateurs whose interest in the genus far outweighs any knowledge of botany. So classification of Haworthia has muddled on with scant regard for the discipline of botany as a science. Whether that has changed, is not for me to say. I have personally been gathering information on distribution and variation for over 50 years and have very seriously tried to keep that in the context of the science I was trained in and present it in a manner that botanists can follow and hopefully accept.

What has developed is that academic and professional botanists have been working with the tools of molecular biology and the results of five independent studies have all pointed towards the same conclusion, which is that the species of Haworthia are elusive, and the related genera are also not adequately distinguishable in the DNA data.  The best solution they can offer is to merge the genera back into a single genus, namely Aloe.  My personal reaction is that this is not a new idea and also Gordon Rowley pointed this out as far back as the 1970’s.  I have also said that the subgenus Haworthia does not sit comfortably with the other two subgenera.  Had I been a true taxonomist I would have implemented that by separating Haworthia into three separate genera and that is what I really would like to see.  But the reality is that this does not solve the other problems that exist regarding Astroloba, Chortolirion, Poellnitzia, Chamaealoe, Leptaloe, Lomatophyllum, and the small Madagascan aloes.  True botany alone can resolve the current and a new classification (still in manuscript form) has been proposed by a group of scientists that will really ‘rock the boat’ as far as collectors are concerned.

In Haworthiad (2012:4), I wrote about Haworthia mirabilis ‘submagnifica’. (Ed. note: The name in inverted commas, according to the author’s system indicates a variant name rather than a formal conventional variety, subspecies or form.  It is his contention that there is no species definition and thus formal names have a large element of uncertainty.  Another option is to drop the use of any rank denotion at all).  It is one of the first populations linked to von Poellnitz’ H. magnifica long before so much was learned about distribution and variation.  I used the prefix “sub” because this means “somewhat”, “almost”, “slightly”, “partially”, and possibly a few other words that mean… it is, but it is not.  The population concerned is Komserante (Figs 1-2) and this particular population has acquired the name H. vernalis (Figs. 3-4).  But I think we need to start from scratch and drop all the ‘baggage’ of the years.  I personally have learned so much since I wrote my revision in 1996 that I know it is not possible to properly backtrack and retrace the passage forward by the use of Latin names.  Interfertility is the basis of the system we use to identify and describe species and my field experience was already proving that this cannot possibly apply in the way in which Haworthia has been, or is to be, classified.

It is quite evident that H. retusa and H. mirabilis, both of which I accept in a very much broader context, do hybridise and there are populations that fit between.  But first let me just explain that I regard H. retusa now to include H. turgida and all the variants of that species (nomenclatural priority obviated the use of the name turgida to cover the greater body of populations for this species).  In the same way I regard H. maraisii, H. magnifica, and H. heidelbergensis and whatever variants were attached to those, as H. mirabilis.  There are thus two species.  My further observation is that H. pygmaea and H. mutica are segregates from the common gene pool of H. retusa and H. mirabilis.  The Komserante population is the one in which that same gene pool is re-combining (Figs. 5-10).  I am not in the least sure of all the intricacies but it seems to me that it is actually the group of populations that I recognize as H. retusa var. nigra that is pivotal in the relationship of all these species that I recognize. In this we discuss populations using names as prescribed by convention. This convention caters for chronology and authorship and not for evolutionary pathways. Both the names “retusa” and “turgida” precede the name “nigra”, but the populations that I now assign to H. retusa ‘nigra’ may better fit the concept of evolutionary origin.

The picture is complicated by the role of H. floribunda. This also hybridizes with both H. mirabilis and H. retusa as odd hybrids as well as at a population level. Just what are we to do? History has demonstrated all too well that a bevy of ill-assorted interested parties trying to impose a botanical classification is going to produce nothing but conflict and confusion. This has been going on now since the time that Smith, Von Poellnitz and Resende were simultaneously describing new species. How are we going to turn around and arrive at the understanding and stability of names that we seek?

In the past I have been extremely reluctant to make the following suggestion, and even now am a bit hesitant. What we need to do is turn to people who are employed to do this work. Herbaria and herbarium botanists are tasked and entrusted to classify and name plants. Perhaps it testifies to the complexity of the subject, or just its enormity, that these botanists have too often needed to defer to amateurs who have the interest, energy and enthusiasm and commitment to acquire field knowledge that a professional could never get the time or funds to do. The unfortunate part is that sometimes amateurs may not be able to relate their knowledge adequately to academic botany.

So what is the solution?  It is that the community leaders assume the responsibility for the establishment of a system of classification that is meaningful to the community they serve.  (By community, I mean initially the botanists who should be providing us with scientifically sound classifications, then editors who are familiar with what botanists do, next are the Societies with their memberships, and also opinion formers in those groups. Finally included are the reviewers and commentators who lead opinion in one direction or another).  It is surely not that difficult to sit down together to discuss and arrive at a set of guidelines by which a decision can be reached as to what (not whose) system to accept. A solution does not belong to anyone. Latin names are assumed to refer to an entity called a “species”. Botany has indeed been very lax and remiss in not providing a definition and this is the prime reason why amateurs have had so much freedom in generating Latin names for the most frivolous reasons. Botanists themselves have often not been far behind.

I think it is time to change all this and must excuse myself from any decision making body or process because I have a vested interest in respect of all the words I have written on the subject.

M B Bayer
PO Box 960
Kuilsriver 7579
South Africa

Email: bbayer227@gmail.com

Literature cited:

Bayer, M B(1999) Haworthia revisited. Umdaus Press, Hatfield.
-(2012) Plants in my collection 7: H. mirabilismagnifica’. Haworthiad 26(1): 4-5

The absurdity of taxonomy and nomenclature?

In Alsterworthia 13.1:6 (2013) there is yet another statement about the correct name for a species of Haworthia.  It reads …”The vexing matter of the correct name for Haworthia pumila has taxed some of the finest minds in botanical nomenclature”.  The article then goes on to replace that name with H. margaritifera with an explanation so simple that it casts considerable doubt onto the quality of those minds that have examined the problem. There is of course also a difficulty in that the quoted sentence implies that H. pumila is the correct name, while the article goes on to dismiss it.

The fact is that Linnaeus listed four different things (varieties) under a single name Aloe pumila, and the only issue was about which of those four things ends up with that particular first name. It so happened that Burman in 1701 made a choice, and was followed by Aiton in 1789 who chose something else.  So the name Aloe pumila stood but applied to two different things (species). Duval was unaware of the earlier Burman choice and used Aiton’s choice when he created the genus Haworthia.  Dr L. A Codd, whom I would have accepted as a fine mind (and also as a very ethical man), advised C.L. Scott that Aiton’s choice was in fact illegitimate and hence also Duval’s usage in Haworthia.  The opinion was that Burman’s choice was the first and also thus the legitimate one; and it could not be denied by the illegitimacy of the Aiton usage as a later action.  So perhaps it was/is a question of rank or just an opinion that Aiton made up pumila as an entirely new name.

There is nothing complicated and mind boggling about this simple state of affairs. Or is that so?  What on earth does the ICN as the product of presumably fine minds actually say about this? Does it take 50 years of debate to establish such a simple fact? The situation is further exacerbated in that the finest taxonomic minds are involved in an epic battle to either create a single alooid genus or many lesser genera. It appears that the latter option is winning ground although the war against single-species genera has surely not been abandoned. When the dust finally settles, it will be recognised that the taxon onto which this unfortunate species viz. Haworthia pumila/margaritifera resolves, will be a separate genus, probably Tulista, and then the truly correct name will be Tulista pumila. Or will it?

My personal opinion that however the case may truly be judged, the correct answer is the intent. Scott and Codd came to a workable end point way back in history and it has been my misfortune now to have defended that. I think there is a parallel in the case of Aloe bainesii. Put into use by Reynolds far back in history, it is found that the name barberae had page priority and thus preference. In what interest was the change made? Why does the code have a conservation facility for names? The fun seems to be in the argument rather than in usage.

The argument that I think L.A. Codd would have made is this. There are four varieties covered by the Linnaean epithet pumila. The first effective use of that epithet for one of the four was to the warty t10 of Commelin and that is how the name is formally typified.  To use of that same epithet at any other time for any other of those four Linnaean varieties would be illegitimate.  It is also not in the least certain that the name margaritifera is correctly typified by Wijnands on the same Commelin illustration t10. I aided Wijnands to this conclusion before myself stumbling on the fact that its correct typification would be on a Bradley illustration.

There is a curious twist to the issue and it is somewhat of an oversight that the persons involved never read the introduction to Haworthia Revisited. I explained the problem and also in respect to the correct application of the original name margaritifera to what we know as H. minima. I also cited the name H. pumila with the authors as (L.) Bayer to make it clear that I was not accepting the name with the authors (L.)Duval as Scott cited it. I thought at the time that it was a mistake on Scott’s part. I had also written to Dr Codd specifically about the issue and this is when he explained to me (as a professional taxonomist and fine mind) that the illegitimate use of the name pumila in Haworthia did not prevent the correct usage. It only strikes me now that he probably had advised Scott to the effect that the NAME as Duval had taken it through to Haworthia was correct, even if he had applied it to the wrong species. This whole issue has not been properly and fully aired. To argue that it is a new name seems to me just a piece of intellectual vanity that serves no purpose other than to demonstrate our collective failure to honour the intent of the code – or respect the dismay of interested person.  A last point I make is that people can and will always find topics to disagree on, so this is an important trap to avoid and be mindful of. It is not particularly in the case of nomenclature that this seems to happen. I had no doubt at the time when I made the decision to accept Scott’s usage that no matter what my decision was, cause would be found to change it.  If I had decided on either margaritifera (correctly typified) or maxima (as I. Breuer later did), this would also have been argued as wrong.

[-ed. There seems to be a number of taxonomic changes brewing. Time will tell whether pumila survives.]


1. Haworthia margaritifera/pumila
Dr. John Manning. S.ANBI.

The vexing matter of the correct name for Haworthia pumila has taxed some of the finest minds in botanical nomenclature. Since I do not include myself among their company, I was not in the least surprised to find that I had misrepresented the situation. Thanks to expert input from Roy Mottram and Urs Eggli we can now put the matter to rights.

The issue of the correct name for Haworthia pumila starts with the fact that in his original publication of Aloe pumila, which forms the basis for this species, Linnaeus recognized several varieties, but without explicitly listing the typical variety, thus he did not list Aloe pumila L. var. pumila. Linnaeus’ Aloe pumila was subsequently effectively lectotypified by Burman f. (1701) [and later in enor by Scott (1978)] against the illustration in Commelin’s Horti medici Amstelodamensis, which is also the type of var. margarit!fera. This renders the name margaritifera homotypic with Aloe pumila L. (i.e. they share the same type). As the autonym (i.e. following automatically from the species name) for this species, pumila would normally have statutory priority over margarit(fera BUT, in the interim, the combination Haworthia pumila (Aiton) Haw. (1804) had been published, based on the name Aloe arachnoidea var. pumila Aiton, a quite different species that we know now as H herbacea. The publication of this combination renders Haworthia pumila (L.) Duval (1809) an illegitimate later homonym and thus not available for use in Haworthia. Because the combination Haworthia pumila cannot be used for Aloe pumila L. as a result of its prior usage for some other taxon it must be substituted with the next available valid and legitimate epithet, which is margaritifera. Note, however, that in any genus other than Haworthia the epithet pumila is the correct one to be used for this species.

The formal rendering of this situation is as follows:
Haworthia margaritifera (L.) Haw. (1819). Aloe pumila var. margaritifera L. (1753).  Aloe margaritifera (L.) Burm.f (1768).  Aloe pumila L. (1753). H pumila (L.) Duval. (1809), hom. illegit. non H pumila (Ait.) Haw. (1804). Lectotype, effectively designated by Burman f. in Prodromus florae Capensis: 10 (1768) [Superfluous lecotypification by Scott (1985)]: Illustration in Commelin, Horti medici Amstelodamensis, Pars altent: t.l 0 (1701): Aloe Afric: folio in summitate triangulari margaritifera, flore subviridi.

2. International Code of Nomenclature for algae, fungi, and plants (Melbourne Code)

3. Aloe pumila, Haworthia pumila; what or who is confused?  ISBN: 0-9534004-4-1 Bruce Bayer. Alsterworthia International Special Issue No.3. https://haworthia-updates.haworthia.org/aloe-pumila-haworthia-pumila-what-or-who-is-confused/


4. Commelin, Johannes, Horti medici amstelodamensis rariorum tam Orientalis, vol. 2: t. 10 (1701)
Commelin t10 1701 H. pumila


5. Commelin, Johannes, Horti medici amstelodamensis rariorum tam Orientalis, vol. 2: t. 11 (1701)
Commelin t11 1701 H. pumila


6. Curtis’s Botanical Magazine, vol. 33: t. 1360 (1811) [S.T. Edwards]
ST Edward 1811 Curtis Bot Mag v33 t.13608348


7. Moninckx, J., Moninckx atlas, vol. 3: t. 12 (1682-1709)
http://dpc.uba.uva.nl/cgi/i/image/image-idx?c=botanie;view=entry;cc=botanie;entryid=x-421058064 and


8. History of Succulent Plants,  Bradley, Richard (t30) (1716)
Bradley t30


10. History of Succulent Plants,  Bradley, Richard (t21) (1716)
Bradley t21

Ed. – another …

11. J., Moninckx , Aloe Africana, folio in summitate triangulari / Margaritifera, Flore subviridi. / C: Commelin, Hort: Amst: Part: 2. pag: 19. Wijnands, D.O., The botany of the Commelins, Rotterdam 1983, p.134