- Volume 4, Introduction
- Volume 4, Chapter 1:- That squadron of Haworthias from Albertinia eastwards.
- Volume 4, Chapter 2:- A glimpse of the super-species Haworthia nortieri
- Volume 4, Chapter 3:- More new things and ideas in Haworthia
- Volume 4, Chapter 4:- Some variation in Haworthia mirabilis var. sublineata
- Volume 4, Chapter 5:- What did I learn yesterday?
- Volume 4, Chapter 6:- Comments on Haworthia mortonii I.Breuer
- Volume 4, Chapter 7:- The brutality of the reality of Haworthia.
- Volume 4, Chapter 8:- Closer to closure.
- Volume 4, Chapter 9:- Closure
- Volume 4, Chapter 10:- Post-closure
- Volume 4, Chapter 11:- Haworthias – Small Relatives of Aloe
- Volume 4, Chapter 12:- Variation in Haworthia with Particular Reference to Haworthia Glauca, Baker.
- Volume 4, Chapter 13:- Haworthia and Nomenclatural Confusion
In trying to close my long history as a writer about Haworthia, I am anxious that my closing thoughts are more understandable than my opening ones were. Update 4 calls for a “paradigm shift”- for me as much as anyone else. My friend Kobus Venter has written…”I feel that a lot of important descriptive and analytic content gets lost by reducing the species to this level (of superspecies)”. My intention is completely otherwise. My view has altered in the sense that I recognize and admit that all these new names and descriptions of writers like Masa Hayashi or Ingo Breuer are extremely useful and informative and that we are losing content in arguing and disagreeing about them. My contention now is that our problem lies in the fact that we are trying to explain and understand these complex systems things within the context of a restrictive nomenclatural system that is not designed for the purpose. It is confounded by the problem that as a society we do not understand what species are.Continue reading
I wrote a short note for Haworthiad, to explain a picture of Breuer’s new species H. fusca (MBB7507), and said “… the fact is that it is from a small population just west of Albertinia en route to another of Hayashi’s (?) species H. esterhuyzeniae, and also to Breuer’s H. vincentii. As readers we are being conditioned to accept that there are many kinds of species such as biological species, morphological species, taxonomic species, good species, bad species etc etc. so a latin binomial could mean anything (and the word ‘tautology’ has been added to my vocabulary). Botany needs a sensible and practical handle to a squadron of populations from between Albertinia and Great Brak. I would gladly supply this if somehow I could be assured that the act was not seen to be the clown’s contribution to the circus.”
Without any assurance, but with the encouragement of Stirling Baker, I am going to try and produce an explanation.
Put very bluntly and without any apology to a group of people who definitely deserve better, my life experience is that taxonomy is largely a farce despite the fact that it works surprisingly and exceedingly well. I have already written around the subject a number of times and do not want to repeat what is not necessarily true other than the contribution these thoughts have made to my personal psyche.
In this contribution I am discuss, illustrate and then propose that there are just two species, H. retusa and H. pygmaea in a complex where presently more than nine species and varietal names are being used. I do this in consideration of all the populations of Haworthia known to me in the winter rainfall biome. Thus I recognize the need to rationalize species like H. mirabilis (which will then absorb H. maraisii, H. magnifica and H., heidelbergensis, and H. retusa (which will absorb H. turgida. There is a major problem in that the populations indicate three species in the west, viz. H. mirabilis, H. retusa and H. mutica but these appear to fuse or morph to two in the east. My past treatment of species and varieties like maraisii, magnifica, acuminata, dekenahii, argenteo-maculosa will bear witness to the nature of the (my) problem.Continue reading
Barry Phipps, in an article reprinted in Haworthiad 20:61, writes that “the term species is a concept”. Donald Levins in “The origin, expansion and demise of plant species” devotes a chapter to “The premise and species concepts”. There is no dearth of literature and the entire subject is indeed, as Levins suggests, a subject of “heated debate”. Levins also quotes from the literature, “… the idea of good species … an artifact of the procedures of taxonomy”, and “… our system of names appears to achieve a reality which it does not possess”. It is comforting for me to read his premise …”that the species is a dynamic entity that undergoes alterations in its gene pool, variation pattern and geographical distribution”, and his advice…”thus it is best to take a pluralistic approach to species’ passages in time, combining genetic and ecological perspectives”.Continue reading
Latin names definitely mean different things to different people and my contention is that the real essence of these names should, in addition to their many other usages, be in the relation of plants to their origins, relationships, behaviour and imagined future. A classification can only have the authority that experience and knowledge permit, and be really evaluated and understood by persons with the same evidence before them. In coming to closure I have been exploring some more and with my wife Daphne, made two finds which further convince me that we have to come to a classification by agreement. However, the requirement is that species are seen to be highly complex systems with none of the rigidity and inflexibility that nomenclatural rules imply, nor any of the egocentric authoritarianism that a history, of which I have been a part, suggests.
Statistical analysis of two populations of Haworthia mirabilis (V.Poelln.) M.B.Bayer
M.B.Bayer & L.M.Loucka
In discussing H. rossouwii (Aloe 38:31, 2001), Bayer mentions the possible continuity with H. mirabilis var. sublineata. But any comment like this is complicated by the problems of variation, description and circumscription. We want to discuss the variation in the latter element and indicate further where the problems are in the delineating species and varieties. It seems that one of the assumptions of classical plant taxonomy is that of linear dichotomy, black and white, this species or that, and also that there is hierarchical and consistent in-group similarity to some unstipulated degree. Haworthia, and particularly the subgenus Haworthia, presents a problem to those interested in the genus in that the classification is confused and that identifications are difficult. Attempts been made to explain that the classification is confused by the perceptions associated with classical taxonomy, and that the sharp and precise discontinuities suggested by a ‘key’ to the taxa, simply do not occur in the subgenus Haworthia, in fact they do not occur in many other genera, and this simple truth seems to be difficult for some to accept.
Thus this article includes a report of a study done on a batch of seedlings of H. mirabilis var. sublineata. It shows that there is very little probability that one could quantify separation of this from other populations presumed to be the same species.Continue reading
I was in the field yesterday (March 14th -2007) and then in reflection thought I would relate it to why I write and to what I have written. Someone had been at Sanddrift Drew to look for the Robustipedunculares that grow there, and reported that they could not find H. marginata. This was a bit disturbing to me because that marginata has very slender long leaves and in the vicinity it also hybridizes with H. minima and H. pumila. The particular locality is a fairly prominent flat-topped hill which seems to have been formed from river gravel. Despite being so rocky and fairly steep-sided, the hill has been very severely impacted on by agriculture. The southern Cape soils are very skeletal and agriculture is fortunately concentrated on the lower flatter slopes and to the alluvial flatter areas and eroded shales which can be machined to lands. Rainfall is in winter and distribution is very variable across the landscape. Rainfall patterns have also apparently changed with time, at least as agriculture seems to have developed. There have also been economic and social changes which have altered the fabric of agriculture. There was a time when farming was a way of subsistence. Tractors and fuel was cheap and there was an endless space to tame. The consequence is that huge areas of very marginal land was ploughed and contoured for cropping. This was the fate of most of the Sanddrift hill and H. marginata was thus reduced to a narrow band of Renosterveld vegetation above the very last contour reaching to near the top of the hill. The particular farm seems to have teetered on the verge of failure as both a subsistence farm and a commercial venture for the last forty years. Several very dry periods in that time have driven various owners to financial despair. Presently, however, the farm seems to have fallen in to the hands of what may be a new form of commercial colonialism. It is owned by an english gentleman who has the resources to farm aggressively. Water sees to have been obtained from an expanded and more flexible irrigation scheme and the farm has entered a new phase of development. This is of course happening throughout the country and the threats to the fragments of undisturbed vegetation and rocky outcrops which have given me so much joy are now hugely disturbing.
Haworthia mortonii I.Breuer was published in Alsterworthia International 7(1):22(2007).
In Alsterworthia 7(1):22 Breuer states “No records have been found to indicate that this plant has been discovered before and as it is dictinctive I have decided to name it as a new taxon”. This population is recorded in the old collecting record of G.G.Smith and I searched on the calcretes further to the east as far back as 1969. Unfortunately it never occurred to me then to even look at the remnant of rock in an area largely destroyed by road-building operations. Presently this small ravaged quartzitic outcrop is bisected by a meaningless road which is fenced and I did find the plants there in 2004 – name the place SW Karsriver. Why I looked is because of the mindless destruction of a small valley habitat on the Karsriver about 3km further northeast where a magnificent form of Aloe brevifolia once grew with a population of H. maraisii that has gone with it. I was thus anxious to confirm a maraisii so close to Bredasdorp for reasons best explained elsewhere (Update 3 Chapter 1). Morton Cumming apparently found more than the three plants I saw there across the fence on the north side. I recognized the plants as minima/marginata hybrids and was also a bit nonplussed by the absence of putative parents. Minima was only known at Mierkraal far to the southwest and marginata is known about 10km further to the northeast. I was disturbed by the fact that I could only find the three plants and in February 2005 I visited the site again and collected seed under MBB7453. Cumming seems to have been at the site also early in 2005 and claims to have seen many plants, which surprised me. In the past the site has been grossly disturbed and a constant pain to me is that major road-construction in the late 1960era led to the use of rock outcrops such as this, as gravel sources. The badia-locality at Napier became a major gravel source and could be seen as a huge white scar on the landscape from afar afield as Swellendam. Thus this site at Bredasdorp suffered the same treatment and the land surface has been transformed with the removal of surface rock and gravel. Only the smallest fraction is left and I do hesitate to report the survival of “maraisii” on virtually a single quartz rock remaining on the south side of the road pictured in Alsterworthia. I cannot believe that I would have missed any plants in the area available to be searched. Farming in the area is not mainly devoted to “merino-sheep and grain crops”. Farming in the area has become highly commercialized and water is exported from afar afield as the Theewaterskloof Dam at Villiersdorp. Grain crops are unreliable and with this artificial supply of water, farmers have turned to ostriches and dairy cattle. The result of feed-supplementation has resulted in higher stocking densities and greater trampling and damage to natural vegetation. This has put tremendous pressure on pockets of surviving vegetation that is also exacerbated by a turn to dual purpose Dohne-Merino sheep breeds that graze more aggressively than the original Merino. Additional to this is the destruction of roadside vegetation in what appears to be a deliberate policy of road-engineering to clear verges to the farm fences, and the dreadful application of herbicides for the fear of weed-seeds contaminating crops from those road verges. The possibility that this herbicide application and disturbance of stable natural roadside vegetation will certainly lead to greater weed problems in the future, is left for that dark future.Continue reading
My experience is that Latin names definitely mean different things to different people. I submitted this manuscript as a draft to various people and the response varied from one which was nil, to some sort of general accord. I am, however, no longer confident that botanists either do or will agree with my contention is that the real essence of Latin names should, in addition to their many other usages, be in the relation of plants to their origins, relationships, behavior and imagined future. A classification can only have the authority that experience and knowledge permit, and be really evaluated and understood by persons with the same sort of evidence before them. In coming to closure I have been exploring some more, and with my wife Daphne, made two finds which further convince me that we have to come to a classification by agreement. However, the requirement is that species are seen to be highly complex systems with none of the rigidity and inflexibility that nomenclatural rules imply, nor any of the egocentric authoritarianism that a history, of which I have been a part, suggests.Continue reading
During the time I have worked with plants, I have met many botanists and taxonomists and I particularly had the opportunity to associate closely with one of the most prominent in succulent plant taxonomy. I could never hope to emulate the energy, application, thoroughness and zeal with which that person approached the subject, nor the academic and written achievements. The sharing of ideas was however, a problem and I never felt much more than student. My discomfort with the taxonomic product of this persons work eventually resulted in alienation and eventually I wrote in frustration…”Taxonomy as a science has to answer the question “Are species real?” starting and ending with proper definition of the word/concept.”Continue reading
Recently I have been in communication with three recognized botanists and have their written admissions that…1. “Taxonomy is in a mess.” 2. That the question of species is “highly controversial”. 3. “The current framework for decisions (for taxonomic decision making) is riddled with flaws, but it is the only one we have. Someone who knows the plants has to make decisions.”
I do presume to have some knowledge of the plants and hence I made a decision to submit a list of names which I think could serve the need of a botanical reality. However, the very botanist who had suggested who should make the decisions then commented …”It is interesting that all of the ‘new’ discoveries (e.g. H. cummingii to name one) must be forced into the existing classification”. I asked if there was any evidence that force was required to do this. There was no reply.
My conclusion has to be that the botanical nomenclatural and classification system is flawed and that there is actually no way in which Haworthia can be satisfactorily forced into that system. Therefore there is no further contribution that I can make. There is still a huge amount of fieldwork that could and should still be done, but I cannot see that any new records or observations can significantly improve any classification that is connected to the traditional systems and escape the controversy invariably generated when more than one taxonomist becomes involved.
It is now evident in all this that human sensitivities are of far greater consequence than sensibilities. While a classification may be an apparently intellectual and truth-finding process, it may be nothing more than an easily accessible arena where minds can create an illusion of being so occupied. I am deeply sorry that I have thus offended and hurt people by my own activities there.
This note is not strictly after closure because Cameron MacMaster (Cameron knows the plants, especially the bulbs, of the E Cape intimately and was instrumental in the re-location of H. marumiana many years ago.) sent me a picture (Fig.1) of a Haworthia from Glen Avon Falls east of Somerset East some time ago and this has been a lure to me ever since I saw vdW287(PRE). It should be noted that this specimen is cited, I must note a sentiment of considerable reservation which was not conveyed by the rigidity of print, in Haworthia Revisited (p.67) under H. decipiens var minor… “3225 (Somerset East): in valley behind Bosberg (-DA), van der Westhuizen 287 (PRE).” I have visited the Bosberg in a weak attempt to locate such a plant after a fruitless attempt to determine who and where the collector was and is. The area is intimidating in its vastness as are so many of the hills and mountains of the Cape and with so much still to explore, this area has not been a priority. In fact I have just recognized that while I wrote Revisited in response to pressure, my subsequent exploration has been to seek validation for my own comfort rather than to try and impress anyone. This recent visit to the Bosberg is only because an odd opportunity arose for me to revisit my friends (Ian and Sandi Ritchie) on Kaboega, coupled with interest from a distant botanist acquaintance in Prof. Richard Cowling. Prof. Cowlingis one of those rare botanists from whom I have really learned something to think about rather than just to remember. I had contacted him because in my correspondence with Jan Vlok about the vegetation of the Mossel Bay area, he had copied responses to Prof. Cowling. The outcome was that I was introduced to Dr Syd Ramdhani who is now contracted under Cowling to study the biogeography of Bulbine as a post-doctoral task. Dr Ramdhani studied Kniphofia and works in the molecular-biology laboratory of Rhodes University managed by Dr Nigel Barker. Dr Ramdhani is now also tasked and occupied with a feasibility study of Haworthia as a target group for extended biogeographical research where H. cooperi has been suggested by me as a possible fruitful area of interest. (These botanists have been warned not to be influenced by Bayer!) So I have been aware that the MacMaster plant could signify a replicate of the Kaboega/Helspoort/Plutos Vale/Baviaanskloof/ complexes which suggest that H. cooperi and H. cymbiformis may be one species. My visit to Glen Avon Falls was then added to the familiarization of Dr Ramdhani with Haworthia on Kaboega.Continue reading
Printed in Excelsa 4:17 (1974)
There are few succulent collections which do not include haworthias, although these small and insignificantly flowered plants are not good garden subjects. Their size, and shade and shelter requirements make them better suited to intensive cultivation in raised containers under shelter. Very popular with collectors especially prior to World War II, the decline in popularity can be attributed to various factors. Although the genus is credited with some 160 species and more than 250 varieties, it is highly unlikely that more than 90 species and perhaps 10 sub-species would survive a critical revision. Many species have been eliminated in recent years, but there are still many maintained only by the mystery of their origin. Hybrids and ill-defined or inadequate species account for many superfluous names. The result is an artificial pseudo-scientific system of nomenclature in which the classic binomial system is prostituted for a series of horticultural cultivars.
Within Haworthia there are real problems of definition and circumscription of the species. The variability within species is often so great that it is very difficult to circumscribe a species in such a way as to exclude members of other species. The species are best recognised as geographical entities and no species can be described without good reference to locality and distribution. This is the only way in which a sound system of nomenclature directly related to field complexes, and hence a “natural system”, can be derived. Names are the fundamental basis of communication concerning the plants, and the psychology of collecting requires good definition of the “kinds” of things being collected. Nevertheless it is surprising how many persons enthusiastically and vehemently argue the “differentness” of things without seriously considering where the boundaries of difference really lie. The system of nomenclature in Haworthia has been so confused that it has not been possible for collectors to name or acquire plants consistently or confidently.Continue reading
Written for, and then printed and distributed by Haworthia Study Group, New South Wales – October 1970.
M. B. Bayer, Karoo Garden, Worcester, South Africa.
Much of the confusion in the taxonomy of the genus Haworthia could have been avoided if more attention had been paid to localities and inherent variability of the species. The tendency has been to base species on single specimens and to regard the species as variable concepts subject to personal opinions. According to Stebbins in his book “Variation and Evolution in Plants”, a species comprises a system of populations separated from each other by complete or sharp discontinuities in their variation patterns, and this must have a genetic basis. Therefore there must be isolating mechanisms to prevent transfer of genes. In Haworthia, most (not all) of the species are found in rock formations and stable situations at moderate altitudes, and hence the populations are well spaced. Haworthias are also insect pollinated, mostly by solitary bees, and as stated by Clausen in “The Evolution of Plant Species”, it is logical that spatial separation of the plant populations coupled with flight limitations of the pollen vectors, will with time have led to differentiation of highly localised populations. A further problem in Haworthia is that the species do in fact exist at different stages of differentiation. Thus one may be forced for practical reasons to regard a widely ranging series of varying populations as a single species, simply because the degree of inter-gradation and variability precludes any other alternative. If there is an alternative, it is to recognise varieties in the sense that this concept has been used in the past, i.e., to apply to individual variants and forms.
Printed in British Cactus and Succulent Journal 4:45 (1987).
Haworthia is indeed a popular genus which seems to inspire a great deal of controversy and confusion. One would have to be very thick-skinned to be able to ignore past history and not plead for forgiveness for similar transgression. I was just busy trying to clarify, in my own clouded mind, the problem of H. pumila (L.) Duval, when I saw Will Tjaden’s little article on the subject in this journal (3:88, 1985). Gordon Rowley in the same issue reviews the recent books on Haworthia and also mentions the H. pumila versus H. margaritifera debate. Coming so soon on the heels of Fearn versus Cole and Walker versus Bruyns, it would be insensible for Bayer to take up the cudgels against anyone.
In any case I frankly do not know what to do about the problem of the name-game so well expressed by both Rowley and Tjaden, and yet I shamefully have to admit my displeasure at their contribution, or lack of it. In the case of Tjaden, I agree with his comments on name changes and respect this view far more than he suggests. My distress at the recognition of H. pumila (L). Duval is greater than Tjaden has conceived, and all the more because I knew that Col. Scott’s solution offered in 1978 was not correct. Col. Scott was assisted in this instance by Dr L. E. Codd, who is one of our most respected taxonomists. Unfortunately they overlooked Burmann’s Flora Capensis of 1869 and also the fact that another species (H. minima) was involved. While I accepted their decision in the interests of stability and peace, Dr Onno Wijnands pursued the matter a little more vigorously.