Volume 2, Chapter 12:- Haworthia rossouwii Poelln. and the demise of H. serrata Bayer

Posted on November 6, 2011 by Bruce Bayer

This appeared as an article in ALOE 38:31 (2001). Unfortunately there was a problem with illustrations and captions and these are corrected here. A comment is also added as an addendum to respond to criticism by I. Breuer published in Alsterworthia 1:13(2002).

Introduction:

I described Haworthia serrata in 1973 (Jl S.AFr.Bot.39:249, see Figs.1) from Oudekraal, southwest of Heidelberg. I commented then on the wisdom of describing a new species when “the recognition, estimation of taxonomic rank and circumscription of elements in Haworthia…” was so problematic. The new species was said to resemble H. emelyae var. multifolia (Figs.2). In respect of its distribution, I said it was closest to H. heidelbergensis at Heidelberg (Figs.3 JDV87/1) and as at Matjestoon (Fig.4 JDV87/3), and also to H. sublimpidula at Swellendam (now known to be H. floribunda var. major (Fig.5 MBB6859, taxonomically with little connection to H. rossouwii). The implication was that it could have been taxonomically related to those elements in terms of geographic distribution. I was still puzzled by the relationships of H. serrata when I wrote (New Haworthia Handbook :55, 1982) that collections by C. Burgers from the coastal limestones might throw more light on the matter (Fig.6 MBB6985 H. mirabilis var. calcarea).

Fig. 01a. JDV87-47 H. rossouwii. Oudekraal, SW Heidelberg.rossouwii 1 043

In his revision of Haworthia (1983), C.L. Scott recognised my species. He confused it, and illustrated it, with a photograph of H. mucronata var. mucronata sensu Bayer (1999), which he called H. mclarenii. This does exemplify the problem of look-alikes in the subgenus, and this curiously does have some connection to the actual problem.

When I wrote Haworthia Revisited (1999), I was still not sure what the real affinities of H. serrata were. I mentioned that my 1982 observations were vague because of the unusual elements which occurred in the coastal limestones. I described these as new: H. mirabilis var. calcarea from De Hoop Nature Reserve (see Fig.6), H. variegata var. petrophila (CBurgers2158) from Karsriver and H. heidelbergensis var. minor from N Bredasdorp (Figs.7 JDV86/5). In my 1999 classification, I placed H. magnifica var. paradoxa (Figs.8 JDV86/78 & 94/89) in H. mirabilis, suggesting that it may have a connection there via the var. calcarea and an element from the Potberg (CBurgers 2018) which I have not yet seen in the field myself (since I wrote the article I have in fact seen this population, MBB7356, and it is discussed in the Chapter re H. mirabilis). The connections of paradoxa must be viewed in its relationship to H. emelyae var. major, in the same way that serrata is compared with H. emelyae var. multifolia. I also suggested that H. serrata had a very close resemblance to some forms of H. mirabilis var. sublineata from south of Bredasdorp. This present paper addresses some of these observations again.

New Records
In June 1999, I revisited H. serrata at Oudekraalkop (MBB166) again, this time together with J.D.Venter. Despite rumours of over-collection, it was still very abundant, although localised. It was also still present at Koppies (Fig.9 JDV99/6) a short distance to the west, but in very low numbers at a badly burnt site. P.V. Bruyns (priv. comm.) has reported it at a more northerly site as well. This could be where J.N.O. Uys also showed it to me at a second site on Oudekraal when he first introduced me to this species. It struck me again how similar the plants were to H. mirabilis (particularly the var. sublineata, Figs.10 MBB6639, bearing in mind the vast variation that exists there) and to H. heidelbergensis var. minor. The visit in June ’99 was a general excursion to explore the reported presence of H. maraisii at Koppies (ex E. Esterhuizen), in relation to that species and heidelbergensis as I know it in that general area. Our finds and observations led us later in the year to explore the area north of the Potberg. The extraordinary finds there led me to further explore westward to Bredasdorp itself and to see for myself the var. calcarea in the De Hoop. Two visits for that purpose were fruitless, but thanks to Dennis DeKok, I did locate it in the company of Lawrence Loucka in July 2000 (MBB6985-fig.11). This latter excursion was particularly fruitful because, by great good fortune, we discovered H. serrata in unmistakable form north of Bredasdorp (Soutkloof, Fig.12a & b MBB6983), and Nooitgedacht, MBB6984). Both sites are west of Rooivlei where heidelbergensis var. minor occurs. We also collected variegata var. petrophila (Fig. 13 MBB6986) west of the Karsriver limeworks. For that variety I have C. Burger’s record (CB2158) from east of the limeworks, and a collection I made at Renosterfontein (Fig.14 MBB6632) on the east bank of the Karsriver in 1997. This latter collection, in particular, reminded me in both form and colour of H. emelyae var. multifolia (see fig.2).

Fig. 10a. MBB6639 H. mirabilis var sublineata. S Bredasdorp.

The conclusion from seeing H. serrata north of Bredasdorp, and both var. calcarea and var. petrophila, is that this is the prime connection. It seems now more improbable that the var. petrophila is as close to H. variegata as I had supposed, and that the var. calcarea is closely connected to both H. serrata and to var. petrophila. The other observations remain valid viz. that there is a strong resemblance between serrata and mirabilis var. sublineata; but particularly that serrata may be connected to heidelbergensis via the var. minor. However, heidelbergensis in its general relationships is extremely complex. It is interfused with H. maraisii, it may be the direct (if complex) geographic extension of H. mirabilis in the context of the relationship between that species and maraisii, and it may have affinities and continuity with both H. variegata and H. floribunda. There is still another problem: H. variegata var. modesta at Kathoek (Figs.15 JDV97/24) and Potberg (Figs.16 MBB6542). My collection of this element at Kathoek (Figs.17 MBB2551) suggests that it is possibly a small very proliferous sand dwelling serrata. J.D. Venter’s collection from the same farm is a more robust element with rather longer, more erect leaves which suggests H. variegata. My Potberg collection (fig.16) is another small element which I relate to variegata although the leaves are shorter and more turgid. It must be borne in mind that H. variegata var. hemicrypta occurs north of the Potberg on the gravelly flat so that there is ecotypic variation in evidence. Further work will have to be done to elucidate what could be an unresolvable situation i.e. the Potberg is home to variants which link all the elements so far named. The evidence for this is already available, but insufficient to crystallise a solution.

Fig. 15a. JDV97-24 H. vaiegata var modesta. Kathoek.

There will be difficulty in considering the extent and the degree of similarity of H. serrata to other populations. Some of these which include serrata-look-alikes are:

Fig. 18. JDV96-52 H. heidelbergensis var . N Kathoek.

Some of these populations and their variants are dealt with in other chapters (Particular note must be made of H. elizeae which has to be considered in relation to H. rossouwii).

H. serrata was coming into bud in July a good five months after mirabilis had started to flower. This shows that my predictive thoughts about the relationship with calcarea and petrophila may not be particularly sound if flowering time is considered. Calcarea flowered a little before mirabilis var. sublineata in January, petrophila flowered in February while Roovlei heidelbergensis and Leeurivier (Drew) heidelbergensis flowered in December and March respectively. Flowering time for other collections needs to be observed, noting that this is not necessarily definitive either (for example while H. mirabilis var. badia is essentially late-summer flowering, single plants may flower in winter.

When I consider how much time I have spent in the area, it was really surprising to find serrata so far west. It means that something very interesting can still be found in the large triangle Swellendam/Bredasdorp/Riviersonderend, and that exploration will have to be done on a very small scale. The Karsriver and Renosterfontein petrophila are just smaller more spinose versions of Oudekraal, and the leaves are more spotted on the reverse. Calcarea was previously known from two clones which had rather shorter leaves and, perhaps, fewer leaves per rosette. This, the locality, and the spotting on the back of the leaves would have been the reason for opting for a relationship with mirabilis. We only found it with quite detailed directions because it was such a small population and so cryptic, consisting of three tiny locations under bush with a total of about 15 clumps. One location could have been the product of vegetative propagation with six to seven clumps. The second was similar with only two clumps and evidence of porcupine activity around the clumps. The third covered about 15sqm and there were another 15 or so plants as clumps or as single rosettes. These did vary and only one clump really resembles the two I have seen in cultivation viz. the Karoo Garden plant of C. Burgers, and a plant I received from Dennis DeKok. Burgers, however, appears to have made two collections from De Hoop; this needs to be confirmed. The plants seen by me in habitat do vary quite a bit and the range of variation equates that of both serrata ex Oudekraal (the Koppies population is reduced to about five plants) and north of Bredasdorp. The mean length of the leaves and leaf number per rosette may be shifted to the shorter and fewer, respectively.

The two Bredasdorp populations of H. serrata are remarkable for the similarity of the plants to serrata at the type locality. The habitat is a little different and at the westernmost of the populations, the plants cluster much more freely than the Heidelberg populations. At Koppies the plants are on a Witteberg substrate, whereas at Oudekraal and N Bredasdorp, it is Bokkeveld shale. We may have a slightly biased image of serrata with turned out leaves; the plants can be quite globose, and I did illustrate a plant like that in my original description when I drew the comparison with herbacea.

Where serrata really differs from mirabilis is by the greater number of leaves per rosette, the thinness of the leaves, narrowness at their bases, lack of a mid‑leaf swelling and by the incurving of the leaf tip; that character is fairly significant. H. mirabilis var. sublineata grown recently from seed has proved to be remarkably variable, but none of the plants have incurving leaves. Some of the clones are very similar to serrata, but the flowering time is earlier in the year and more in keeping with H. mirabilis in that respect.

Discussion
H. variegata var. petrophila and H. mirabilis var. calcarea should be transferred to the species H. serrata. The same may be true for H. heidelbergensis var. minor. However, H. heidelbergensis has a complex distribution and there are other complexities in variation that preclude a definitive statement. It is quite probable in the light of the findings discussed in Haworthia Update Vol.1, that there is no discontinuity which satisfactorily and convincingly can be claimed to distinguish species. This is probably just another example of a more general problem which I have experienced with the identification and classification of many plant genera.

I am conscious that I have not dealt fully with the problem in omitting mention of co-occurrence (I mean sympatry – when two obviously different elements grow together at the same site or very closely adjacent). I see this as the best measure of discontinuity. Thus if two elements grow in close proximity, even if not sharing the same habitat, they are probably discrete. This does not preclude the possibility that they are simply ecotypes and this is taken into consideration. However, I have before pointed out that a taxonomic solution which can be deduced in this way for populations might not be true for the entire distribution of the species concerned. It is evident that serrata generally occurs alone. At Oudekraal and at Koppies, there is a floribunda/maraisii element in the vicinity. In the case of heidelbergensis var minor, both turgida and maraisii are present. I have always been struck by the similarity of mirabilis and serrata, and by the fact that they do not co-occur. Mirabilis, in the context of this paper, is presently not known east of Napier except at Bredasdorp and Mierkraal south of Bredasdorp. This is as the var. sublineata and var. mirabilis respectively, which differ from serrata in respect of flowering time, less leaves per rosette, and the non-incurving leaves. Curiously, it appears that mutica, at least in the Bredasdorp area, grows generally alone too, although at Haarwegskloof (Bredasdorp) it does grow with heidelbergensis. At Drew it is in the close company of both maraisii and heidelbergensis, and south of Stormsvlei is near to a maraisii/mirabilis intermediate. Thus even an element as apparently different as H. mutica may presumed to be, cannot be ignored.

However, another consideration now enters the picture with the discovery of serrata so far west. There are three poorly understood elements which were reported to have come from Bredasdorp and Napier respectively. The first of these was H. bijliana von Poelln. that does, however, seem to belong rather with H. arachnoidea than with anything else. G.G. Smith appears to have had a plant of this ilk which he received from Maj. Venter 9, from Caledon. The other two, however, are H. altilinea var. bicarinata Triebner and H. rossouwii v.Poelln. They were both described from the same collection viz. Napier at Bredasdorp, Rossouw in Triebner 1059. The former was never illustrated and the description is rather brief … “Backs of leaves always with two keels and with teeth. Leaves 3-5cm long, 6-8mm broad, with 4-6 dark lines in lighter part, with two keels at back, keels with up to 2mm long denticula”. This description is in the joint paper by Triebner and von Poellnitz, but authorship is attributed to Triebner alone. von Poellnitz later retained this variety when replacing the name altilinea with mucronata (note that in the context of the names which I use, Scott confused my serrata with mucronata as well). This is very curious because it is evident from the description of H. rossouwii, which is very much more detailed, that another plant from the same collection is in fact again described. The differences are essentially that von Poellnitz gives the leaves as 5-6cm long, and 8-10mm wide as opposed to the respective 3-5cm and 6-8mm by Triebner; and with three lines on the ‘end surface’ as opposed to four to six by Triebner. This says a great deal about the detailed descriptions which are routinely called for, and which in Haworthia seldom amount to much because of the problem of look-alikes, and the variability within and between populations.

I repeat the von Poellnitz description here to illustrate that it is a very good description that nevertheless omits some key information:

H. rossouwii von Poellnitz spec.nov. (Stemless rosette, spirally many-leaved. Leaves rather pale green, nearly oblong lanceolate, acuminate, on the face somewhat retused near the apex thus forming a triangular face; on the back, towards the apex, with sub-pellucid tubercle-like spots, denticulate on the margins and keels; the triangular face strongly acuminate, sub-translucent, not tubercled, but carrying some sub-pellucid small teeth, and traversed by a few longitudinal lines).

Stemless many-leaved rosette about 5-6cm in diameter. Leaves more or less erect, 5-6cm long, 8-10mm wide, about oblong-lanceolate, tapering gradually, pointed, slightly widened at the base, almost straight or a little bent to one side near the tip, rather light green, dull. On the face flat or usually somewhat convex, near the tip slightly bent backwards (retused) at an angle of 20 degrees; on the back, from the middle outward or near the tip obliquely keeled, or somewhat more rarely with two keels, near the tip with a few, often elongated, very often raised slightly pellucid spots, and frequently with a few leaf-coloured tubercles. The end-surface half-pellucid, 20mm long or somewhat longer, 7-9mm wide at the base, triangular, tapering very gradually, pointed at the tip often slightly curved inward, somewhat convex, smooth, rarely with a few indications of tubercles, but with some semi-translucent teeth (these teeth loosely arranged in a lengthwise middle line, now and then also in another line nearer the margin and very rarely scattered about in small numbers) with three long, occasionally interrupted, green lengthwise lines, of which only the middle one may reach almost to the apex, and usually with a few very short line; leaf margins and keel with pale teeth, or near the base often leaf-coloured, teeth, up to barely 2mm long; end-bristle pale, with small side bristles, 5-7mm long.

… On account of the teeth on the end surface stands near to H. schuldtiana and to H. paradoxa (I treat these respectively as H. maraisii and H. mirabilis var. paradoxa) but is easily distinguished from both. Its flowers are thus far unknown”.

The omissions are the flower of course, and there is no stipulation of the approximate number of leaves, and leaf thickness. The weakness is that it is a single plant description, evidenced by the fact that another plant from the same collection is accepted as a variant of a totally different complex.

In the past I have I regarded rossouwii speculatively as a synonym of H. mirabilis, due largely to the fact that it was recorded from the Bredasdorp area (and to the ambiguity of the type). Another reason was the similarity I observed between the illustration of H. rossouwii in Kakteenkunde with H. heidelbergensis var. minor and with H. mirabilis var sublineata. I opted for the latter (with which Scott was in accord) and the similarities are also recorded in the discussion above. I dismissed bicarinata as insufficiently known because I assumed that Triebner may have had some better reason to have equated his specimen with the Little Karoo H. mucronata. Possibly there has been a mistake in the Triebner numbers. It is this discovery of serrata so close to Bredasdorp, and equidistant from Napier, which revives and also casts new light on the problem. I conclude that my H. serrata is a later synonym of H. rossouwii of von Poellnitz.

There are still two other considerations. In my 1999 revision, the fact is that I placed paradoxa as a variety of mirabilis while discussing the possible connection of these elements via calcarea. In the light of this paper it is evident to me that paradoxa could also be linked to serrata rather than with mirabilis. The same is true for emelyae var. multifolia. I would not like to commit myself to this probable solution at this stage, as I think more evidence should be obtained. It is also improbable that, however attractive, the solution will not avoid impacting on H. emelyae, H. magnifica and H. heidelbergensis. It is also evident that the requirements of the ICBN are that should paradoxa indeed need to be incorporated into serrata, more name changes will result, as paradoxa will have priority over rossouwii. My opinion is that this is a fundamental weakness in the code, which inhibits speculative treatments, and also which results in smaller taxa becoming the typical main element of a species. My further opinion is that it is a weakness of the Code that the description of an element automatically creates an equivalent taxon. This may be acceptable and desirable where the elements are clearly separable and geographically defined, but not where the typical element is required to absorb any other variants which are not so defined. Thus H. paradoxa var. paradoxa could become the main component of a species where it is actually a geographical isolate. In a system which does not have an adequate general definition for ‘species’, this probably does not matter; whereas it might if there is a definition which suggests that the ‘species’ is an operating living system (see Bayer in Asklepios 77:3, 1999).

The formal statement of this paper, which would better be regarded as an hypothesis subject to test, is thus as follows:

H. rossouwii von Poelln. in Kakteenk.7:75 (1938). Type: Napier near Bredasdorp, collected by Mr Rossouw, South Africa Police in Napier, Triebner 1059. Not preserved. Lectotype: designated by Breuer & Metzing 1998, icon in Kakteenk. non syn. H. mirabilis sensu Scott 1985, Bayer 1976, 1982, 1999.

H. altilinea var. bicarinata Triebn. in Triebner & von Poellnitz in Feddes Repert.Spec.Nov. 45:170 (1938). Type: Napier at Bredasdorp leg. Mr Rossouw (=Triebn.1059). Not preserved.

H. serrata Bayer, Jl S.Afr.Bot. 39:249(1973). Bayer :55(1976). Bayer :147(1999). non Scott :62(1985). Type: CAPE‑3420(Bredasdorp): Oudekraalkop, Heidelberg (‑BA), Bayer 166 (NBG).

Material seen:- 3420(Bredasdorp): Soutkloof, Bredasdorp (-AC), Bayer 6983; Nooitgedacht, Bredasdorp (-AC), Bayer 6984; Oudekraalkop, Heidelberg (‑BA), Bayer 166 (NBG); Koppies (-BA), Bayer 4902 (NBG); N. Oudekraalkop (-BA), Bruyns 6260 (NBG).

H. rossouwii var. calcarea (Bayer) comb.nov. H. mirabilis var. calcarea Bayer in Haworthia Revisited :110(1999). Type: CAPE-3420(Bredasdorp): De Hoop (-AD), C. Burgers 1648 (NBG, Holo.).

Material seen:- 3420(Bredasdorp): NNE. Buffelsfontein, Potberg (-BC), Burgers 2018 (NBG). De Hoop (-AD), C. Burgers 1648 (NBG), Bayer 6985.

H. rossouwii var. petrophila (Bayer) comb.nov. H. variegata var. petrophila Bayer in Haworthia Revisited:159(1999). Type: CAPE-3420(Bredasdorp): Renosterfontein (-AC), Burgers 2158 (NBG, Holo.).

Material seen:- 3420(Bredasdorp): Renosterfontein (-AC), Burgers 2158 (NBG), (-CA), Bayer 6632; Karsriver (-AC) Bayer 6986;

The provisions of this solution are that the epithet paradoxa may be instated preferentially, and that emelyae var. multifolia and variegata var. modesta also be included.

A second provision is that the species H. bijliana v.Poelln. be rejected as insufficiently described and sourced, and that the type (the illustration in the Berlin herbarium) is ambiguous – as indeed are many Haworthia types and descriptions based on single plants and not correctly tied to geographical origin. This is demonstrated by the citation by VPoelln. (Feddes Rep. 1936) of this species viz. bijliana from Klawer and Eenriet and also Feddes Rep. in 1937 from Springbok – which cannot be anything other than H. arachnoidea. In this last publication he cites a specimen from Bonnievale, another from Ezeljacht Oudtshoorn and also sinks fergusoniae here which in fact was supposed to have come from ‘near’ Grahamstown.

H. bijliana Poelln. in Feddes Repert. 27:134 (1929); Bredasdorp, Mrs va der Bijl. Type van derBijl s.n. in (B). Not preserved. Lectotype desig. Breuer 1999, unpublished photo. icon. (B). Species rejecienda.

Acknowledgement
I am grateful for the company on the field trip of Lawrence Loucka of Connecticut (USA), and that of my wife, Daphne. The assistance of Paul Botma of Cape Nature Conservation is acknowledged over and above the general acknowledgement to that Department. Mr. C.L. Neethling, Mr. Thys Swart and Mr. Pieter deKok were most kind and helpful in respect of access to sites. I am also grateful to Kobus Venter for support, advice, and constructive exchange of ideas. Not least to Steven Hammer, with comment from Bob Kent, who was so kind as to read this manuscript critically and make corrections. Residual errors will be mine.

Addendum
Alsterworthia Vol 1:13(2002) “A comment on Bayer’s latest taxonomic contribution” by Ingo Breuer. [link] With reference to the comments in Alsterworthia 1:13(2002) regarding the identity of H. rossouwii and H. serrata:

Notes

Fig. 27 A copy of the von Poellnitz lectotype of H. rossouwii.

Figs 28a & b Black and white profiles from two angles, of the same one plant actively growing, undessicated and turgid. The plant is a clone from Bayer 6984 Nooitgedacht, NW Bredasdorp. This is correctly H. rossouwii, and correctly H. serrata.

Figs 29a & b. The colour originals of the preceding.

Fig.30 A second plant of MBB6984. This is a more vigorous grower and it shows the differences that obviously confound the uninitiated. There were not many plants at Nooitgedacht. I only collected from two clones and this is a photograph of the second.

Fig.31 A photograph of a plant of MBB6983 Soutkloof, north of Bredasdorp. Showing a plant in which the convexity of the mid-upper surface (and concavity of the lower surface) is virtually absent. I could have, from this sample (MBB6983), produced pictures to match Figs.27 to 29. So no one should claim that Fig.30 is a different species as someone now well might.

Figs 32a & b. Scanned and manipulated copies of figs 28a & b.

Fig.33 Flowers of MBB6672 H. maraisii Koningsrivier, SW Robertson.

Figs.7a, b & c. These are clones of JDV86/5 H. heidelbergensis var. minor, Rooivlei, NNE Bredasdorp. This is a small population, of also small plants, from northeast of the collection MBB6984, Nooitgedacht. The plants partly resemble H. rossouwii from there, and partly the var. petrophila from Karsriver. Classifying them as a variety of H. heidelbergensis is not necessarily correct. Considering habitat and substrate, one must consider that ecotypification is playing a role, and that was habitat available, there would be further populations which would confirm continuity with these known collections.

Regarding Figs.28a & b. A bit of play with light and focus and the keel and under-leaf spotting could be varied. I would like to suggest that they be considered them faded, less sharply focused, printed with less contrast and on a coarser grained paper. Figs.32a & 32b are in fact such scanned copies of Figs.29a & b. I do not think it even necessary to consider that the original rossouwii of Fig.1 endured a long journey in the post to a foreign land. The assertion by Breuer in Alsterworthia is that not only are the plants I figured as H. rossouwii different from Fig.1, but that this Fig.1 lectotype is “probably” of the maraisii-complex. This is at variance with…

1. the Triebner description of the same collection as a variety of H. mucronata;

2. with Col. Scott who regarded it as H. mirabilis. What to say of von Poellnitz’ own assessment – the man who described both species i.e. maraisii and rossouwii in the first instance.

3. with the facts of the pictures before you.

What should an observer make of maraisii growing very near to rossouwii at Oudekraal and near to rossouwii at Napier? Can we really see a closer resemblance of Figs 27 & 28 with those long attenuate, double-curved, thin leaves – to H. maraisii rather than to H. serrata. I truly do not see that such a judgement can be seriously considered in the light of Breuer’s interpretations. It is of course valid when one considers all the variants that I illustrated in my article above and in terms of my over all classification.

Generally these plants of the SW Cape tend to have the double curvature of the leaves as is evident in the VonPoellnitz lectotype, but one can find in the same population and/or taxon, clones with incurved, outcurved or erect leaves (see fig.30). Broadly speaking H. maraisii has thick recurved leaves. But this is a non-argument even if one (outside of a “lumping vs. splitting” red-herring) considers the complexity of the so-called maraisii-complex, and I am sure that Breuer does not. I frankly think that most observers cannot even dream how complex it is and that it is just braggadocio to write as though anyone can. Breuer implies that one can make the inference of similarity between rossouwii and maraisii from the illustration (Fig. 27), the description and its given locality. This is patently and self-evidently false as is evident from the fact that I used this same information to reasonably deduce the similarity of rossouwii and serrata.

I did not originally submit a copy of the von Poellnitz lectotype, perhaps because I felt that the response “you will see that rossouwii is quite a different plant from serrata“, is what I could have expected from an uninformed audience! The fact is that all the evidence, circumstantial and descriptive, show that they are the same. Including the lectotype would have just been “overkill” and I have never before felt required to write for a readership with less than common sense or basic knowledge, nor for obstructive readers.

It should not be necessary to say this, but the character of the flowers cannot be specified in the way that writers are inclined to suggest. They have this same enormous range of variability and it is just fraudulent to say that there are floral characters by which these taxa (the varieties of H. rossouwii which I now recognise) can be unmistakeably differentiated. It is the typological concept which drives people to think there is a single description which can encompass the description of a taxon. This is nonsense. It is a statistical problem and we have the difficulty of establishing the probabilities associated with “decision”. Breuer writes “… von Poellnitz’ description probably depends only on 1 or very few selected plants and no other records are reported for this taxon”. This is circa 1945 circumlocution, it is unnecessary and it is untrue. There was never a question of “selection”, and furthermore we have the Triebner description of the same collection as H. altilinea var. bicarinata. Why this sudden doubt about the interpretation of types. It is a shifting of goalposts.

There are few collections in flower now in April, but I could take this picture of three flowers from the one collection MBB6672 H. maraisii – Koningsriver, SW Robertson (Fig.33). It is not an exceptional case or an exceptional collection. But one can see the differences in thickness of peduncle and variation in the individual flowers. It can happen like this, albeit to lesser degree, on the same plant. Colour is also frequently quite variable between and often within collections. Many years ago I undertook to illustrate all the flowers in my maraisii collections. But they were so variable that I just gave it up. The variability in the flowers mirrors the variability of the rosette and the latter is just a little easier to deal with. One has the added problem with flowers, of the changes which take place during the opening and aging process. So then how does one define the flower, say, of H. mirabilis. It cannot even be done for the range of leaf rosettes, and this has now been shown in the literature many times.

May I also point out that one of my understandings of botany and plant classification is that there is a tendency to overreach ones talents. I have freely admitted that I am there because of the paucity of talent. I frankly do not think the environment is enriched by the particular article I now refer to in these added notes.

I can point out that there are writers who really persist in flogging dead horses. The result is phantasmagoric fanfaronades. The article concerning the name H. correcta (Alsterworthia 1:6, 2001) is not particularly accurate either and indeed it may be my own fault. Smith explained that Mrs. Blackburn did not in fact collect correcta ‑ it was a Mrs. le Roux and the plants came from near Vanwyksdorp. Later Mrs. Ferguson sent a plant from 26 miles east of the town. Thus from this information H. correcta has to be a later synonym for H. emelyae.

Regarding types:- the painful realisation was actually expressed by Schelpe in the distant past, and brought home to me many times. These old types are doubtful and ambiguous. I was faced with that option long ago – just forget them all, or try to reach a compromise with the understanding and information available at the time. H. rossouwii is a case where there is real new information which would have made me use the name rossouwii in 1976 and before, had it been available. But here, had I persisted with the name serrata for this new material MBB6983 and 6984, there is absolutely no doubt in my mind that I would have been criticised for failing to see the connection to rossouwii. Not that this would concern me unduly, for I think there is actually very little benefit in this mindless re-interpretation of types which takes us nowhere. Notwithstanding, and without compromising, anything so far written:- the really disconcerting thing about the whole matter is that without the locality data, it will be possible to generate an argument bolstered by illustrations, to show that rossouwii was in fact H. decipiens, H. cooperi or H. herbacea (among others), of the option less improbable than H. maraisii.

The closing paragraphs of the article are a rather hackneyed parody sung by most “wannabe” taxonomists. Of course it is right when Breuer says if we lump it means we would have to lump many other things. It is just as true to say, if we split we have to split many other things. That does not make sense either. This is ancient stuff of 60 years ago and it seems strange that it still provides so much fodder for writers, who have in fact no rational species concept to begin with. The Linnaean system was based very largely on floral characters and hence taxa at all levels are based on “related floral characters”. To suggest that this pertains in some special way to “series” is not correct. This sums up the article in Alsterworthia. ♦

Volume 5, Chapter 8:- An extension of H. rossouwii

Posted on March 3, 2012 by Bruce Bayer

What always comes to mind as I travel through the countryside is the realization of just how much there is to explore. It takes only an hour of driving from Cape Town to get to the start of Haworthia habitats from any of the three main routes inland. The roads do not always take in the best routes in respect of suitable or inviting habitats to explore, and besides there is the question of landownership and permission for access. In recent months my wife and I decided to really make an issue of new exploration and investing time and energy in contacting landowners and looking at places that we have ignored before because of access difficulties. The result has been a massive set of new finds in respect of populations not previously known to us. Having other interests such as in Drosanthemum and chameleons has also led us into places we might not have otherwise ventured.

This particular note arises from another chance find. Heidelberg is very rich as far as Haworthia is concerned and I have written quite a lot about the area or referred to populations there. It is a very important area for both H. retusa and H. mirabilis, as well as for H. floribunda and one assumes that the area has been fairly well explored. The Duiwenhoks River offers much suitable Haworthia habitat and I can count at least 30 populations along the drainage system that can be referred to those three species systems.

While checking on two populations of H. retusa ‘nigra’ (the informal way in which I now cite my own combination H. mutica var nigra derived from a G.G. Smith record south of Heidelberg), we took the opportunity to venture into a field from which we had on the previous occasion been excluded by the presence of ostriches. This was on the farm Diepkloof that I have cited as Morning Star because the two units are now farmed by the same owner and there is also confusion with farms on the east bank of the river also referred to as Diepkloof. The populations we looked at were of H. mirabilis and H. retusa ‘nigra’. The former appears to incorporate H. floribunda in all its populations down the Duiwenhoks River to as far as the change from Bokkeveld shale to Calcareous limestone near Vermaaklikheid. H. retusa var turgida occurs in various guises along the cliff habitats along the river while in non-riverine flatter areas H. retusa manifests.

We were specifically looking for H. mirabilis or H. retusa when my attention was drawn to an old flower stalk. There are a few bulb species that have a very similar dry inflorescence as Haworthia so I was a bit cautious when I bent closer to examine its source. With my search pattern set on the expected, I at first had difficulty focusing clearly on what was there before me – a small form of H. rossouwii (see MBB7803 Figs 1-9). We started looking wider and found a few plants under bushes until our eyes began to get the message as to what we should be looking for. To our amazement plants began to spring up all over the place among the dense pebbles.

Why Haworthia rossouwii? Firstly I have no sympathy with contending classifications that set out to do nothing more than weakly describe variation in the genus in terms of Latin binomials. My contention is that species are complex systems that need to be understood as highly variable elements that can respond to environmental differences and changes. H. rossouwii is already known to have an unusually wide distribution range as far as Southern Cape species were concerned. It is known from north northwest of Bredasdorp and is now known to us at 8 localities southwest of Heidelberg. Essie Esterhuyzen is reported to have found it at Voorstekop close to the N2 about 90km from the most southwestern population.

I relate “H. elizeae” to H. rossouwii. This was probably first recorded by Derek Tribble from the Bromberg mountain near Stormsvlei, about 40km north of the Bredasdorp populations of this species. There it is in sandstone, unlike the ferricrete and shale habitats the species is found in elsewhere. The Bromberg is also about 90km west of Morning Star. The similarity of the two populations is mostly in respect of size and the flowering time (without suggesting that this is inarguably evidence for sameness). The Morning Star plants are less proliferous in habitat at least, and this may simply be because slope and substrate so strongly relate to vegetative proliferation. The plants may get to as much as 50mm diameter under the protection of bushes, but in the exposed pebbles they average between 20 and 30mm. The colour seems to be darker green than the yellowish shade of the more general H. rossouwii but we saw plants in their stressed summer garb where there is a strong shade of purple in the plants. It will be interesting to see what the plants look like in the winter.

That this Morning Star population can so readily be allied with the Bromberg population, for me strengthens the view that the ‘systems’ approach to which I more strongly lean, is correct. What does worry we is that the formality of the nomenclatural systems, both botanical and horticultural, becomes very problematic. Essentially the infraspecific categories of subspecies, variety and forma are group categories derived in an era, and for plants, where less variability was known. In many species it has been relatively easy to add horticultural names and this may be because the flowers convey the interest and significance of difference. Where this is transferred to vegetative differences that are so dramatically affected by growing factors it will be very difficult to police. There is of course the additional problem of a taxonomy that is so personalized. Will anyone actually be able to establish when a published name is/was effectively a single plant description and hence a cultivar name as opposed to a group name? My view is that for the system to work, variability has to be limited and furthermore there is a complication where one now relies on vegetative characters that are so dependent on growing conditions – unlike the flowers of conventional horticultural cultivars. In Haworthia we may have an unusual problem in that many very similar looking species are involved and cultivars (single clones, bred or selected from nature) from different species may be very similar. I cannot personally see that anyone is going to successfully, meaningfully and usefully disentangle group and individual plant names. In H. rossouwii there might not be a problem as there is not a great deal of difference among the plants of the main body of populations that would excite the taxonomist. There is no doubt that there is enough variability to invite selection by the ardent grower who may develop a special interest in the species. The variant ‘elizeae’ and now ‘Morning Star’ (an informal and workable way of distinguishing the plants) may present problems in that the only way that they might be distinguished is if the collecting data remains attached, and with, any plant cultivated.

Acknowledgement
I am very grateful to Coetzee and Sarita Uys of Morning Star, to access Diepkloof, and to Gerhard Marx for useful comment and opinion. ♦

Volume 5, Chapter 13:- A February 2009 Miscellany

Posted on March 17, 2012 by Bruce Bayer

7807 H.minima. Swartrug, SE Heidelberg. 002

This chapter is based on recent field exploration and embroiders around many aspects of Haworthia species discussed in earlier chapters. What should be striking is that new populations follow the very predictable geographic pattern that all my earlier exploration has exposed and in my estimation confirm in every way what I consider a sound and satisfactory taxonomic solution and help explain its limitations.

1. Haworthia minima.

Two new populations of this widespread species are recorded:

MBB7807 Swartrug, SE Heidelberg. This is a steepish east facing slope. The plants are small, the leaf length barely exceeding 50mm and with a tendency to form clusters in the shallow clay banks that rift the area. There are many plants in quite a small area and it curious to see them within very large clumps of Euphorbia tridentata. This Euphorbia itself has a strange geographic distribution being known at Riversdale, Calitzdorp and then at Cradock in the Eastern Cape. (see Figs 1)

7807 H.minma. Swartrug, SE Heidelberg 003

MBB7813 NW Skeiding, E Tradouw Pass. This is a high rainfall area and we were expecting to find H. mirabilis in the lower pressure bursts and white clay that can be seen from the farmhouse far away. But instead we came across H. minima at the highest point of the hill among sparse grass. They are rather green in colour and it is interesting to note in the one plant pictured that it has non-tuberculate upper leaf surfaces and white cartilaginous margins and keel of the leaves. (see Figs 2)

2. Haworthia rossouwii.

MBB7803b Morning Star, S Heidelberg. Morning Star was known to J. Dekenah but the area has been very developed since those years. It was very surprising to find this small form in abundance at the top of a high hill in ferricrete pebbles and virtually no vegetation ground cover. However on this subsequent visit we crossed through an internal farm fence and found the plants in abundance about 150m further away and over quite a large area. We later looked at a lower promising hillside and small area nearer the Morning Star homestead and found the plants again. (see Figs 3)

Looking from Morning Star to Kransrivermond 097

3. Haworthia mirabilis.

This item reports on 6 populations, three of which are new. They confirm the continuity down the Duiwenhoks River and also southwards and westwards from east of Riversdale through to west of Robertson and Greyton and Napier to the south of that. Attention is drawn to south of Heidelberg where the ‘enigma’tic relationship of this species with H. retusa is suspected.

MBB7808 Swartrug, SE Heidelberg. This farm is well known as the source of ‘Haworthia chromatica’ that I dismissed as an element in the complex surrounding the e H. retusa (mutica) ‘nigra’. The names Droekloof and Doringkloof have been used while the map reference gives Diepkloof for a large area extending to west of the Duiwenhoks River. The plants are on an east facing boulder terrace in a stony low bush site with some grass. The plants are small and show the expected wide range of variation. They are fairly similar to the plants in the lichen patch just east of Heidelberg that I have always mistakenly taken to be the origins of H. heidelbergensis, but here are subtle differences that mark a population difference, but I will come back to this. (see Figs 4)

Looking from Swartrug towards Riversdale.

MBB7809 Koeisekop, SE Heidelberg. This is on the same farm and a similar ferricrete hillside southwards. There are several hilltops by the same name in the general area and I cannot even speculate on the origins of the name (“cowshead”). The plants are larger than in the previous population and very abundant. The similarity to populations in the Swellendam and Riviersonderend area is in my opinion striking. Odd clones are miniature images of H.mirabilis from the southwestern populations west of Napier. (see Figs 5)

MBB7220 Morning Star, S Heidelberg. I have discussed this population before and I repeat it here because I did not have many field photographs. It is only 300m from the Morning Star MBB7221 H. retusa ‘nigra’’ population and they flower and seed virtually in unison. Therefore they probably also reflect on the strange interaction between the two major systems. What I have surmised is that H. floribunda gets absorbed into H. mirabilis at the southern limits of its distribution and in these pictures there is clear evidence of the rounded and flattened leaf tips of that species. Therefore we may actually here have a three way species interaction. Reinforced by the presence of three different things at Kransriviermond, covered later under 4. H.retusa ‘turgida’. (see Figs 6a and b)

MBB7221 Morning Star

MBB7811 Kransriviermond, S Heidelberg. Populations further down the Duiwenhoks river have been reported on and this one fall within that mould and the same one as the previous Swartrug and Koeisekop populations. The population is smaller and the plants too are quite small. (see Figs 7)

MBB7814 Skeiding, W Heidelberg. This area is also reported on but digital photography makes it so much easier to record the enormous variability that such populations exhibit. Some of the plants are typically ‘atrofusca’ while others have leaves ended in an awn. Leaf surface may be smooth and there is even an indication of smooth leaves. What is notable is the absence of H. floribunda from what is the sort of habitat it can be associated with and can one can speculate its absorption into H. mirabilis with leaf shapes that demonstrate this. H. floribunda does appear again about 15km to the southwest in association with H. retusa and in the absence of H. mirabilis. (see Figs 8)

MBB7233 Die Plotte, Heidelberg. “H. heidelbergensis” correctly has its origin in this near vicinity and these small summer flowering elements are certainly part of a large assemblage of populations in the central area of what I now come to see as all H. mirabilis. Here discussion must pass to the following. (see Figs 9)

4. Haworthia retusa ‘turgida’.

A difficulty that I experience is in the need to dismiss the impression and general idea we have that there are tiered ranks. H. retusa has many populations and past treatment has placed most of the variants in H. turgida. To suggest that these are really two separate systems is not realistic and confounds any explanation for a few anomalies that exist.

MBB7810 Tierkloof, SE Heidelberg. Tierkloof is quite a deep valley that pushes out of the Duiwenhoks to the east. We found this huge population of large clump forming plants and several such populations are known just north of Heidelberg itself. I have applied the epithet ‘longebracteata’ to these and this is no more satisfactory than generating names for each of a very wide range of populations. There are populations along the Duiwenhoks that are far more inclined to the ‘turgida’ element and Essie Esterhuizen wrote a very good account of the host of variable populations that he encountered. (see Figs 10)

H. retusa 'turgida' at Tierkloof, Swartrug 044 — H. retusa ‘turgida’ at Tierkloof, Swartrug

MBB7812 Kransriviermond, S Heidelberg. We only saw three plants at this locality and these plant mirror the preceding, if a bit smaller. The problem here is that we also have the element I myself described and named as H. retusa ‘mutica’ and I originally linked this “variety” with H.. mutica following what G.G. Smith had done and for predictive reasons. The fact that ‘turgida’ now occurs with it is a huge hurdle to cross. Think carefully. (see Figs 11)

MBB7804 Kransriviermond. I have written about his population in the chapter “Haworthia enigma”. This explains that the plants are not all leaden-black as perceived. They are spring flowering – as ‘turgida’ is. However, the range of forms and colour virtually replicates the plants in MBB7721 at Morning Star (pictures in the “enigma” chapter) where they are spring flowering. Across the river from both these populations is a weak population of small plants of H. mirabilis (7811 above) summer flowering. We know that this major difference in flowering season is not a total barrier to hybridization. (see Figs 12)

MBB7234 Die Plotte, Heidelberg. This is a population of large clump forming plants on a north slope about 300m south of MBB7233 H. mirabilis ‘heidelbergensis’. It is spring flowering. When I first saw these plants I dismissed (actually I never dismiss anything – I maintain reservations as I do now) these plants as large variants of ‘heidelbergensis’, and actually collected one magnificent specimen that looked to me just like H. mirabilis, say, from west Napier. Looking at the range of variation one is compelled to concede that here again is an infusion of H. mirabilis into a population that is primarily H. retusa in that vast shadowland it casts with ‘turgida’. (see Figs 13)

Conservation
I add these comments for several reasons surrounding the poor image that collectors have in the eyes of conservationists, and the very rickety fence I therefore occupy. There is a note reprinted in a recent issue of the newsletter To the Point. This taken from Times magazine and seems to be a rather hyped up condemnation of widespread destruction based on a view of internet websites. These are also monitored by RSA law enforcement that is rightfully disturbed by the high number of locality and collector citations that are indicative of illegal collecting. I personally no longer apply for a “collecting” permit for the prime reason that I am concentrating on photographic record, as a herbarium record no longer serves any better practical short term purpose. The herbaria are overburdened and I prefer living plants to dead ones. After 70 years of field activity I feel treated like a pariah and reduced to subservience under less-informed inexperienced people operating under a rigid and oppressive legislation aimed at acquiring a prosecution rather than wisely trying to direct activity in a positive direction. This activity of collection is, and I have no doubt about this either, a human right imbedded in the very reason for creation and our place in it. Conservation has its roots in the passion that people have for nature and it is nurtured by experience, contact and knowledge of its varied components. It is just ridiculous that one can go to any animal or plant centre here in South Africa and see plants and animals from anywhere else in the world and none indigenous. It is Ok to, say, keep Madagascan Chameleons in captivity where it is someone else’ responsibility to secure them. But keeping local ones is taboo? It is OK to freely sell cacti that do not occur here but are now being dug out in tons in (if that is really true). Recently it has become illegal to so much as possess Encephalartos latifrons and even the National Botanic gardens can no longer propagate and sell this plant. While we talk “plant indigenous” on all public fronts, the fact is that the acquisition, cultivation and sale of indigenous plants is viewed in the most negative light – a viewpoint encouraged by conservators.

This is control by law, a large degree of pure ignorance and by improper application of power derived from legislation. This is not the way to go. It is quite evident from the Times magazine article that legislation has the negative effect of creating a false value and glamour to discovery, Latin names, acquisition and possession. I believe that knowledge and understanding is true power, not legislation and enforcement.

The collecting numbers, localities and information provided here is to promote understanding and knowledge of plants, and thereby to promote their continued existence against all the vagaries of nature that “threaten” them, least of it which may be actually human greed.

Acknowledgement
I am glad to acknowledge the company, comments and interest of Gerhard Marx and whose organization sceptisism I also value. Landowners always impress me with their generosity and graciousness in allowing us access. On this occasion they include Mr. and Mrs. Nelie and Wimpie Jacobs of Diepkloof, Mr. Cloete and Belinda Fourie of Melkboom (B&B), Mr. and Mrs. Coetzee and Sarita Uys of Morning Star, Messrs. Christo and Pieter van Deventer of Doornvlei, Mr. and Mrs. Neels and Anne-Lise Uys of Skeiding (B&B) and then Ms. Jennifer Steggie of Heidelberg. In view of the comments on conservation noted above, I note that there are several farms that now offer accommodation and an outdoors experience and the opportunity to view these plants in their extraordinary natural surroundings. ♦

Haworthia flowers – some comments as a character source, Appendix 4

Posted on May 12, 2012 by Bruce Bayer

No conclusion is written to this appendix. It is evident to me that there just is no way for me to generate a composite picture for each set of flowers by which one can adequately compare. In general the summer flowering cf. H. retusa set have flowers that are correspondingly lighter coloured than those of the darker flower of the correspondingly darker H. mirabilis set. While gathering the plant pictures from files it struck me how similar plants are from quite different sets across both groups and persuading me that H. retusa and H. mirabilis are in fact one integral system and H. mutica and H. pygamea are western and eastern offshoots.

Acknowledgement
I must again appreciate the kindness and helpfulness of landowners in allowing access. Neels and Suzanne Smit of Volmoed; Hector Odendaal of Dankbaar; Jon and Cindy Webber of Klipport; Tom,Trevennan and Hesphia Barry of Van Reenens Crest, and Coetzee and Surieta Uys of Morning Star. The present owner of the Bromberg site could not be established. The other plants photographed are not field plants and neither can they be seen as any more than flowers of one or few cultivated specimens with provenance already acknowledged.

The following additional populations and plants were observed:-

1. MBB7954 H. mutica, Volmoed.
2. MBB6512 H. mutica, Klipport.
3. MBB7741 H. mutica, Dankbaar.
4. & 5. MBB7920 and MBB7921 H. retusa (nigra), Van Reenens Crest.
6. MBB7803 H. rossouwii, Morning Star, S. Heidelberg.

In addition I include pictures from plants in cultivation:-

7. MBB7758 H. retusa, Skietbaan, S Riversdale.
8. MBB7780 H. retusa (geraldii), Komserante, E Riversdale.
9. MBB7781 H. retusa (foucheii), Komserante, E Riversdale.
10. MBB7776 H. retusa, Pienaarsrivier, W. Riversdale.
11. MBB6747 H. pygmaea, Vleesbaai.
12. MBB33 H. comptoniana, Georgida.
[ed.] MBB33 doesn’t exist in Bayer’s Accession, correct reference is most likely KG114/72

The population H. rossouwii (elizeae) at Bromberg, Stormsvlei was visited but the plants were only in very early bud.

The Heidelberg H. rossouwii is a small solitary plant and only known to me from two populations. H. rossouwii (elizeae) is also small, proliferous and very problematic. It is so far only known to me as one very restricted population. I doubt if the eastern end of the Riviersonderend Mountains have ever been adequately explored to exclude it from there. Even the Bromberg alone could yield more populations.

MBB7954 H. mutica, Volmoed.

2. MBB6512 H. mutica, Klipport.

3. MBB7741 H. mutica, Dankbaar.

MBB7920 Van Reenens H. retusa (nigra), Crest.

MBB7921 Van Reenens H. retusa (nigra), Crest.

6. MBB7803 H. rossouwii, Morning Star.

7. MBB7758 H. retusa, Skietbaan, S Riversdale.

8. MBB7780 H. retusa (geraldii), Komserante, E Riversdale.

9. MBB7781 H. retusa (foucheii), Komserante, E Riversdale.

10. MBB7776 H. retusa, Pienaarsrivier, W. Riversdale.

11. MBB6747 H. pygmaea, Vleesbaai.

12. MBB33 H. comptoniana, Georgida.

Haworthia flowers – some comments as a character source, Appendix 10

Posted on May 12, 2012 by Bruce Bayer

Appendix 10 – An additional report on Haworthia mirabilis and Haworthia rossouwii ‘minor’, Rooivlei and Brakkloof, N and, NNE Bredasdorp.

The previous report indicated the necessity for further exploration of Rooivlei. I had observed H. mirabilis, but not reported it in Update 3, at Brakkloof to the west in 2004. So the object of this appendix is to remedy this oversight and to also cover more area of Rooivlei. At Brakkloof there are several small remnants of rocky shale and we located several populations, while at Rooivlei we actually explored the very western boundary. This constitutes the same topographical area as the Rooivlei populations but the plants we observed were factually on Brakkloof.

The populations reported on here are:-

6537 H. mirabilis, Groudini, W Napier
7285 H. mirabilis, Brakkloof 3
8046 H. mirabilis, Brakkloof 2
8047 H. mirabilis, Brakkloof 1
8048 H. mirabilis, W Rooivlei 1
8049 H. mirabilis, W Rooivlei 2
8050 H. mirabilis, W Rooivlei 3
8051 H. mirabilis, E Rooivlei
8045+ H. rossouwii ‘minor’, NW type locality
8052 H. mirabilis, S.Welgegund
8053 H. mirabilis, Welgegund SE 8052

Continue reading →

28. West of Riversdale

Posted on August 16, 2019 by Bruce Bayer

77. 2019.8.12, MBB7776 west of Riversdale, between Riversdale and Heidelberg – Coming to the end of the first chapter of my story. Lets now try something while we contemplate the reality of the difference between mutica and retusa. What are these next 8 plants? I suggest that they are H. mutica – but it is your opinion that matters now. What do you think?

Let me just add something about this DNA sequencing stuff. The technocrats assume that if they have a sample labelled H. retusa, it comes from an entity that truly exists and can be labelled so conveniently. In the one exercise I was involved in I attempted to get the dudes to replicate. How far it got I do not know beyond the first sequencing run presenting some very uncomfortable results. My comments and questions got me thrown out of the project.

Lawrence Loucka: ‘Replicate’ is a statistics term that means to use multiple samples, make multiple readings, to determine variation within (not between) populations. Because of time and expense botanical DNA studies have generally had insufficient sample sizes to be statistically significant. But costs are coming down and quality is improving.

Stephen Boisvert: Replication just means to repeat the experiment or measurement and get the same result. It can be completely meaningless if you don’t satisfy the requirements for philosophical validity – face validity – construct validity or logical validity – predictive, concurrent, discriminant and convergent. Looks like Bruce’s complaint here is with construct validity, concurrent and discriminant/convergent.

The first issue is a bit more complicated. It’s conceptual at the level of what you think a “species” is. Botany (and zoology) has a strange history on this with one with their notion of Type plants (and animals) where a single instance is held as the defacto species standard and entails a whole host of problematic philosophical assumptions (like a platonic ideal form or aristotelian essentialism) which never quite fit the real physical world or the use of concepts in language and has huge sampling problems (one individual chosen to represent a purported population is extremely problematic to say the least). Still I believe if you clearly articulate your assumptions regardless of your philosophical positions on concepts (platonic idealism, aristotelian essentialism, Wittgensteinian familial resemblance and so on) you should be able to produce useful and communicable knowledge. The big problem is being clear enough both in your own head and in your writing about your assumptions which is difficult because of lot of this is stuff we learn and know at an implicit rather than explicit level. You see this when people can identify and distinguish plants but if you ask them how they differentiate they sometimes can’t tell you. They just know implicitly without explicit rules.

Bruce Bayer: Stephen – I truly appreciate your comments. I have been criticized because I many times cannot identify a Haworthia unless I know where it comes from. Written descriptions are fairly useless with many examples to demonstrate the fact. How do you describe the variation in a population when it is difficult to describe a single plant? No matter how unclear the head, the fact is as you see in these last pictures posted, plants from quite different populations (too often identified as different species) can be identical. What really bothers me is that other peoples heads are not clear enough to grasp this statement. I have been pondering explaining my expressed discomfort with the Haworthiopsis paper in Phytotaxa where my discomfort is seen as a personal attack on the authors.

Ronel Kloppers and Sean Gildenhuys have written an outstanding paper with respect to nomenclature and technicality of taxonomy, but which I regard as weak in both scientific method and “philosophy of concepts”. I am hesitant to deal with the issue because I am not in their intellectual league and not in the least sure where my convictions stem from! I am however extremely concerned that the methodology successful perhaps in Haworthiopsis will be a total disaster if applied to Haworthia stricto sensu.

———-

This next set is just another lot from the same place west of Riversdale. Silly me. I think the first would fit comfortably with H. mutica and these now with H. retusa.

Early on in this series I started by going north and west from the Duiwenhoks River south of Heidelberg, and moved west to H. mutica. Now I skip four very relevant populations and travel eastwards. What is happening is we are going to H. retusa. It will take us across area already covered in detail in the Updates under the cover of mutica var. nigra.¹ After that north-east of Riversdale to Kruisriver, further east to the Platkop area, to east Albertinia, to the Gouritz and H. pygmaea. There are three directions northwards to H. emelyae untouched and two southwards that link mirabilis and retusa.

[1]
Volume 2, Chapter 6:- How to understand Haworthia mutica var. nigra
Volume 5, Chapter 10:- Haworthia ‘enigma’ and H. mutica var nigra
Volume 7, Chapter 1:- Haworthia retusa ‘nigra’ – Another grand finale.

78. 2019.8.14, MBB7794 – SE Heidelberg. Unfortunately I do not have pictures of one population that used to be closer to Heidelberg that would also have been instructive. 7794 is one of 3 populations, one of which is commonly known. I would refer to these as mirabiloid retusa. ♦

29. H. rossouwii

Posted on August 19, 2019 by Bruce Bayer

79. 2019.8.14 – I think I am going to abandon the topic of “species”. This is H. rossouwii from a place new to me southwest of Heidelberg. Funny that one plant that seemed to me to be a significant variant, was also the target for a browser.

Steven Molteno: Interesting that the one “marginata-form” plant was grazed. Bristles, like tubercles, could be evolved for defensive camouflage reasons, in the dappled light of a nurse bush. Breaking up the appearance, like the stripes on a zebra?

80. 2019.8.15, MBB7732 – From south of the locality for the original and erroneous H. serrata. It does occur further north near the N2 and might still be found at Koppies. Here it is among dense grass and so very vulnerable to fire as what decimated the Koppies population.

81. 2019.8.16, MBB7803 S. Heidelberg – H. rossouwii is a strange species because it has a few populations near Bredsadorp and a few SW Heidleberg. The plants very similar. But there are oddities on the outskirts of the distribution. This is a small form south of Heidelberg in three population, two of which are probably close enough to be considered as one.

Some more MBB7803 from S Heidelberg. There are no doubt two ways of approaching this. Simply giving them a new name or trying to fit them to existing. The latter is what I try to do – so just follow this little story and see what follows. Even if we go to the large hadron collider we still may not find an answer.

82. 2019.8.18 – Unfortunately I do not have pictures for what I eventually called H. rossouwii var. calcarea – an oddity from the De Hoop Reserve, but this is another oddity from the limestones just east of Bredasdorp. I ended up with this as a rossouwii variant as well for lack of any better idea. The east end of the limestones towards Potberg provides its own complications that better involve H. variegata. ♦

8. Rossouwii

Posted on August 26, 2022 by Bruce Bayer

About 6km northeast of Bredasdorp March 2006. This is what mirabilis is really about – a whole host of populations from Riviersonderend in the west to well east of Riversdale in the east. From inland of Montagu in the north to a report of these plants on the cliffs shore west of Infanta. Small unglamorous, cryptic, often non-descript, infinitely variable, beneath interest to many wannabees. This particular population of rossouwii is a tiny remnant that survived a massive road building program in the 1970s that vandalised surface rock. Do check those leaf ends!

H. rossouwii occurs as 3 populations WNW Bredasdorp with no close presence of mirabilis. Then it jumps a huge distance to SSW Heidelberg where it also never has close association with mirabilis. But at Bredasdorp, east of rossouwii there are a heap of small mirabilis populations that include some curious variants between stubby leaved and elongated leaved, as also degrees of spination. This population is directly north of Bredasdorp.

These plants are not very photogenic as they avoid light and are invariably tucked away in tight spots. Each plant seems to have its own microhabitat and will look different if grown anywhere else. So it is always difficult to fully grasp or describe some kind of common denominator for a population. In cultivation they grow out of character too.