• Table of Contents
• A new variety of Haworthia Limifolia from Natal (1962)
• Haworthia as a problem genus (1970)
• Variation in Haworthia with particular reference to HAWORTHIA GLAUCA, Baker. (1970)
• Changes in the genus Haworthia Duval (1971)
• Anguish Among the Haworthias. (1972)
• Natural Variation and Species Delimitation in Haworthia Duval. – Part 1. HAWORTHIA RETICULATA (Haw.) Haworth (1972)
• Natural Variation and Species Delimitation in Haworthia Duval. – Part 2. HAWORTHIA HERBACEA (Miller) Stearn. (1972)
• Reinstatement of the Genera Astroloba and Poellnitzia Uitew.
• Natural Variation and Species Delimitation in Haworthia Duval. – Part 3. HAWORTHIA REINWARDTII Haw. and HAWORTHIA COARCTATA Haw. (1973)
• Leaf spirals in Haworthia. (1973)
• New Haworthia (1974)
• Name Changes in Haworthia Concerning H. Obtusa Haw. and H. Pilifera Bak.
• Haworthias – small relatives of Aloe (1974)
• Haworthia Duval: Section Retusae fide Scott — Additional Comment (1974)
• The ‘Retuse’ Haworthias (1975)
• Haworthia mirabilis Haworth. (1977)
• Natural Variation and Species Delimitation in Haworthia Duval. – Part 4. HAWORTHIA EMELYAE von Poelln. and a new variety. (1979)
• A Story of Haworthia Nitidula v. Poelln. (= H. mirabilis Haw.) (1980)
• Looking for Haworthias (1980)
• Natural Variation and Species Delimitation in Haworthia Duval. – Part 5. HAWORTHIA ANGUSTIFOLIA Haworth. (1981)
• Observations on the G.G. Smith Collection of Haworthia (1982)
• The Cape Flora and the Karoo (1984)
• Haworthia – Confusion Reigns Again (1986)
• Haworthia and Nomenclatural Confusion (1987)
• Natural Variation and Species Delimitation in Haworthia Duval. – Part 6. HAWORTHIA MACULATA (v. Poelln.) Bayer. (1987)
• Haworthia History – Zurich (1997)
• Fundamentals as I see them (1997)
• Gravitational collapse and black holes in Haworthia (1997)
• Haworthia cymbiformis var. reddii (Scott) Bayer – a test of an hypothesis. (1997)
• Factual information about BB
• Haworthia, why controversy?
• Beware of the dog (1999)
• A shadow of the past – Haworthia arachnoidea again. (1999)
• The intractable problem of look-alikes in Haworthia. (2001)
• Haworthiad Letters (1988–1998)

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Printed in Cactus and Succulent Journal (US), 43:157 (1971).

M.B.Bayer, National Botanic Gardens of South Africa, Karoo Garden, Worcester.

The genus Haworthia is sub-divided into twenty sections principally on leaf and growth habit.  The composition of the sections thus often bears little relation to the actual and natural affinities of the constituent species.  Sub-division of the genus on the basis of floral characters has been suggested by Uitewaal (1947) and reference should also be made to Berger (1908).  In Das Pflanzenreich, under the Section Margaritiferae, Berger particularly comments (citing N.E. Brown) on the problem of garden hybrids, and it is unfortunately true that many species are still recognized which have no real basis in field populations.  These inevitably obstruct attempts at presenting natural relationships, and hence also a desired aim of plant classification.  The inadequacies of leaf morphology as a basis for subdivision is particularly evident in a study of the species H. reticulata Haw., H. herbacea (Mill.) Stearn and H. schuldtiana var. maculata vPoelln..  These species are presently placed in the sections Muticae, Arachnoideae, and Retusae respectively, when in fact distribution, inherent variability, field hybridization and floral morphology demonstrate their unquestionable affinity.

The section Margaritiferae is particularly afflicted with dubious species and there is some doubt that the species H. icosiphylla Baker, H. tisleyii Baker, H. rugosa (S.D.) Baker, H. .cuspidata (S.D.) Baker, H. subattenuata (S.D.) Baker and H. subfasciata (S.D.) Baker can be referred to field populations and thus validated.  On the basis of floral morphology, the species H. attentuata Haw., H. browniana vPoelln, H. fasciata Willd., H. glabrata Baker, H. longiana vPoelln. and H. radula Haw. (if these are actually discrete species), together with H. smitii vPoelln.and H. tuberculata vPoelln. whose affinities are less obvious, can be transferred to the section Coarctatae.  Examination of preserved material in the Bolus and Compton Herbaria (Cape Town), collecting records of Smith, Otzen, Long and Payne, and direct field observation indicate that only four species need to be considered under the Margaritiferae.  The following account is given in explanation of this statement.

The described varieties and related species of H. margaritifera (L.) Haw, are particularly confused and it is fortunate that field populations do not make it necessary to fully clarify the involved synonymy of this species.  Commelin (1701) recognized two species, Aloe africana folio in summitate triangulari margaritifera flore subviridi (t.10) and Aloe africana margaritifera minor (t.1l).  In 1715 he added two more species, one merely with fewer tubercles and probably synonymous with both his t10 and t.11, and Aloe africana margaritifera minima (n.43) which was described as having smaller leaves and tubercles than the variety minor.  Boerhaave (1720) cited four related species but referred only to two of Commelin’s earlier species.   Bradley (1725) described and illustrated a plant which he vaguely referred to Boerhaave.  This is unfortunate because although Bradley’s illustration (t.21) is clearly intended to be the same as Commelin’s minima, it became a source of confusion in later works.  Dillenius (1732) elaborated on Commelin’s species and provided illustrations for separation of the elements minor (f.17) and minima (f.18).
Linnaeus recognized three elements which were based on Commelin’s t.10, t.11 (Dillenius’ f.17) and n.43 (Dill. f.18), Aiton (1789), in retaining three elements, cited only Bradley’s t.21 under his Aloe niargaritif era var. major and yet under the variety minima also refers to Bradley’s species!  DeCandolle (1799) illustrated a plant (t.57) as Aloe margaritifera and this was said by Ker-Gawler (1811) to really have been the variety minor.  DeCandolle had used the epithet media instead of minor, and as Ker-Gawler (1805) had repeated the error it is not surprising that Aiton (1811) added Decandolle’s t.57 and KerGawler’s media to the synonymy of his Aloe margaritifera var, minor.   It is perhaps Aiton’s earlier treatment of Bradley’s t.21 which prompted Haworth (1805) to recognize four elements, namely Aloe maxima (type Commelin t10), Al. minor (type Comm. t.11 and Dill. f.17), Al. minima (type Comm n.43 and Dill. f.18) and Al. major (type Bradley t.21).
Willdenow (1811) appears to have been confused as he described Apicra margaritifera var. major (type Comm. t.10 and Bradley t.21) and var. minor (type Dill. f.18).  He also described Ap. granata (type DeCandolle t.57) and Ap. margaritifera var. maxima (no syn.).  This latter species may have been intended to be Haworth’s Al. maxima.  Salm-Dyck (1817), however, altered Haworth’s Haworthia maxima to Aloe semimargaritifera with three varieties major, minor and minima, and described Al. papillosa based on Willdenow’s Ap. margaritifera var. maxima.  It seems fairly certain therefore that Al. papillosa S.D. and H. maxima Haw. were synonymous. Saim-Dyck retained Al. margaritifera and also its varieties major, minor and minima.

Haworth (1819) now totally revised his species by accepting Salm-Dyck’s Al. semimargaritifera and adding a fourth variety multiperlata.   He altered his H. margaritif era var. major to the species H. margaritifera, retained H. minor, described H. erecta (type DeCandolle t.57) and H. brevis (type Ker-Gawler t.1360), and altered his H. minima to H. granata.  He also discarded his H. maxima in favor of H. papillosa.  The species H. semiglabrata was also described.

Some rationalization has taken place with time and the following species and varieties arising from the above are presently recognized : –
H. papillosa (S.D.) Haw.
Hf. margaritifera var. margaritifera (L.) Haw. var, corallina Baker
var. maxima Haw.
var. minima (Aiton) Uitew.
var. minor (Aiton) Uitew.
var. subalbicans (S.D.) Berger

In addition there are several subvarieties and also the related species H. semiglabrata Flaw., H. poellnitziana Uitew., H. uitewaaliana v Poelln. and H. mutabilis v Poelln.

Field observation clearly demonstrates that all these taxa are misconceived and that historically, confusion revolves around two principle elements.  These are firstly the species typified by both Commelin’s t.1O and t.11, found in the Robertson Karoo and western area (Montagu) of the Little Karoo. This is H. margaritifera  (now H. pumila).  Secondly there is the species found in the Coastal Renosterbos and Machia veld-types and typified by Commelin’s n.43 (Dill. f.18).  This is H. margaritifera var. minima and upheld by the writer as a distinct species, H. minima Haw.  This species is not to be confused with Baker’s illegitimate H. minima for which the name H. tenera v Poelln. was upheld by Uitewaal.

H. poellnitziana was investigated at its type locality at Drew, and a related population was also examined in the same ecosystem some three miles to the north-west.  The type locality is a very restricted area and Mr. G.J. Payne communicated the information that H. marginata var. virescens (Haw.) Uitew. had previously been determined from this same site.  Some specimens collected at this locality by the writer showed evidence of smoothness typical of H. marginata (Lam.) Steam and the presence of hybrids of this species with H. niargaritifera nearby at Ashton indicate that H. poellnitziana may be of hybrid origin.  The population to the northwest can either be considered to be a larger form of H. minima more like those found in the inland areas from Riversdale to Swellendam, or to be an ecotype of H. margaritifera adapted to the sandy soils of the Coastal Renosterbos veld-type.  The problem is illustrated in the accompanying photographs.  For the present, H. poellnitziana can be regarded as a variety of H. miargaritifera.  Plants and seed from the type locality are in cultivation at the Karoo Garden and these will permit a final diagnosis at a later date.

H. papillosa can be dismissed as a variant of H. margaritifera with little further ado.  Apart from having its origin in Commelin’s t.1O, field observations show that any of the attributes by which this species can be considered discrete, are fallacious.  Under good conditions H. margaritifera may grow enormous and often develop an elongated leafy stem.  The density of tubercles is in any case variable and it is not uncommon to find the leaf faces smooth either.  In some specimens the leaves are arranged in conspicuous spiral fashion also.
The discovery of H. mutabilis vPoelln. is attributed to G.J. Payne who recorded it from the farm Mierkraal, south-west of Bredasdorp (also the type locality of H. mundula Smith).  Mr. Payne informed the writer that the species was based on an atypical specimen of H. minima, which was the only relevant species found by the writer in that area.  Thus H. mutabilis cannot be upheld and is reduced to synonymy under H. minima.

H. marginata hybridizes commonly with both H. margaritifera (N. and S.E. of Ashton) and with H. minima (S. of Heidelberg).  These hybrids are undoubtedly the origin of Zantner’s curious paper which appeared in Beitrage zur Sukkulentekunden (1942), the one real merit of which was the statement that H. marginata and H. margaritifera were closely associated species and needed to be considered in the same context.  H. semiglabrata certainly offers no problems and specimens satisfying the description for this species are common in the hybrid swarm H. margaritiferaX marginata near Ashton.  Similarly H. uitewaaliana must be dismissed as another form within a similar hybrid association, if not described from a luxuriantly growing young specimen of H. marginata.

There is some doubt as to the origin and validity of H. subjasciata S.D.  The variety kingiana vPoelln, is quite distinctive and occurs in a different ecological area, notably the Karoid Valley Bushveld of the lower Great Brak River.  Thus H. kingiana is upheld by the writer as a distinct species, the species subfasciata being discarded as dubious.

The four species are thus H. margaritifera, H. minima, H. marginata, and H. kingiana.  All these species have a characteristic heavy branched peduncle to which Berger and N.E. Brown (1878) refer, and for which Uitewaal proposed recognition as a subdivision Robustipedunculatae of his group Hexangulares.  Also characteristic of these species is the abruptly rounded attachment of the perigon onto the pedicel.  This, coupled with the relatively narrowly opening perianth lobes and regular arrangement of the outer lobes, separates the four species from all other Haworthia.  The large rounded seed capsules and characteristic configuration of the empty capsules are also distinctive.  These all suggest a distinct component of the genus at sub-generic level together with the groups Triangulares and Hexangulares proposed by Uitewaal.  The nature and degree of difference between the three subgenera so formed appears to warrant re-evaluation of at least the genera Astroloba, Chortolirion and Haworthia.

The writers concept of subdivision of the genus Haworthia is implemented as follows:-

Haworthia Duval subgenus Haworthia
Type: H. arachnoidea (L.) Duval
Plantae acaules, folia carnosus, pedunculus gracilis simplex, perianthium  ad basim triangularis vel rotundatus triangularis, tubus subabruptus junctus versus pedicellus, stylus brevis flexus, stigma sursum capitatus, capsula elongatus cylindricus.c (The name Triangulares proposed by Uitewaal for this group cannot be accepted on account of Article 22 of the International Code of Botanical Nomenclature).

Haworthia Duval subgenus Hexangulares Uitewaal
Type: H. coarctata Haw.
Plantae acaules vel caulescentes, folia rigidus firmus elongatus vel plantae caulescentes folia abbreviatus incrassatus, pedunculus gracilis plerumque simplex, perianthium ad basirn hexangularis vel rotundatus hexangularis, tubus decrescens versus pedicellus, stylus elongatus erectus, stigma prorsus subcapitatus, capsula elongatus cylindricus.

Haworthia Duval subgenus Robustipedunculares Uitewaal
Type: H. margaritif era (L.) Haw.
Plantae acaules, folia rigidus incrassatus, pedunculus robustus ramosissimus, perianthium hexangularis, vel rotundatus hexangularis, tubus abruptus junctus versus pedicellus, stylus elongatus erectus, stigma prorsus subcapitatus, capsula grandis rotundatus.

The following key divides the genus into the three subgenera : –
1. a – Perianth at base triangular or rounded triangular…………………………… Subgenus Haworthia
b – Perianth at base hexangular or rounded hexangular…………………………………….. 2
2. a – Perianth gradually narrowing to junction with pedicel………………. . . . .Subgenus Hexangulares Uitewaal.
b – Perianth abruptly joined to pedicel Subgenus ……………………………Subgenus Robustipedunculares Uitewaal.

The sections as recognized at present are allocated to the subgenera almost as indicated by Brown (1957), with the exception of the section Albicantes which now falls under the subgenus Robustipeduinculares.  The Robustipedunculares therefore includes the species H. margaritifera, H. minima, H. kingiana and H. marginata.  The sections Albicantes and Margaritiferae can be retained in this subgenus with the exclusion of the dubious and invalid species already noted, and the exclusion of those species transferred to the Coarctatae.  The further correct and natural breakdown of the subgenera will require an intensive study of both floral and leaf morphology.  As already indicated, the present sections are not natural, and natural groups cannot be constructed on leaf structure and arrangement alone.  For example H. marginata is separated from H. margartifera on the basis of leaf armature (glabrous and tubercled respectively) yet flower structure conclusively demonstrates their proper affinity.  It is conceivable that the glabrous H. starkiana vPoelln. and tubercled H. tuberculata vPoelln, may prove similarly related.  Rationalization of the differences between the four species constituting the subgenus Robustipedunculares is relatively easy.  H. marginata is separated immediately by its glabrous leaf surface.  The inflorescence is similar to that of H. marganitifera except that the perianth lobes are white suffused with pink.  H. marginata has been recorded from north of Bredasdorp, west of Napier, south of Swellendam, Heidelberg, Riversdale and also north and southeast of Ashton.  It thus occurs principally in the Coastal Renosterbos veld-type except at Ash ton where it is found in Karoid Broken veld.

H. kingiana is separated by its more brilliant green color, fewer tubercies, and tubercles which are rounded, smooth and hardly projecting above the leaf surface.  Ecologically this species is separated by its distribution.  It is confined to the Karoid Valley Bushveld east of Mossel Bay, although this veld type is also found in part of the Gouritz River Valley to the west.

H. minima and H. margaritifera pose slight problems.  There must be doubt in view of what has been written concerning H. poellnitziana, that these two species are separable.  H. minima is characteristically smaller in the coastal areas, but inland may reach a height of 10 cm. and 8 cm. diameter. Although H.   margaritifera may also be small under adverse conditions, it often reaches a height of 30 cm. and 20 cm. diameter. It is also more coarsely tubercled.  The leaf ground-color in H. minima is grey-green and the tubercles distinctly white, whereas in H. margaritifera the ground color is dark-green varying through to deep brick-red under adverse conditions.  H. minima frequently forms dense compact clusters.  H. margaritifera seldom proliferates and when it does the plants are often characterized by the visible, elongated stems with dried and missing basal leaves.  The color of the outer perianth lobes is usually a distinctive yellowish-brown in H. margaritifera compared to H. minima where they are pinkish-white.  Finally the perigon in the former species may be up to 4.5 mm. in diameter and seldom more than 2 mm. in the case of H. minima.

Ecologically H. minima ocurs in the Coastal Renosterbos and Coastal Macchia veld-types which are associated with sandy soils.  H. margaritifera occurs in the heavier clay soils derived from Karoid shale formations, and in the associated Karoid Broken veld of the Robertson, Bonnievale, Worcester and Montagu areas.  Morphological differences are maintained under cultivation in same soil mixtures and growing conditions.  With those differences in mind, the correct decision appears to be separation at species level.  There is no evidence to support the multiplicity of varieties and sub-varieties presently recognized, and even the variety poellnitziana would be more correctly treated as anomalous.

The sub-genus Robustipedunculares is expected to key out reliably in the following manner: –
1. a – Leaf surface smooth……………………………………….. H. marginata (Lam.) Stearn.
b – Leaf surface tubercled ……………………………………… 2

2. a – Tubercles smooth rounded, hardly raised above leaf surface… H. kingiana vPoelln.
b – Tubercles rough, distinctly raised above leaf surface………… 3

3. a – Leaf color gray-green, plants small (to 10 cm. high) outer perianth lobes pinkish-white… H. minima Haw.
b – Leaf color dark-green, plants large (to 30 cm. high), outer perianth lobes yellowish-brown…

….. H. margaritifera (L.) Haw.
Leaf color is not a reliable criterion for separation of these species as obviously under artificial conditions the usefulness of this chararater may diminish.

LITERATURE CITED
Uitewaal, A. J. 1947. A first attempt to subdivide the Genus Haworthia based on floral characters. Desert Plant Life 19; 133-138.

ACKNOWLEDGEMENT
The writer wishes to acknowledge the interest, encouragement and assistance received from Mr. F. J. Stayner, Curator of the Karoo Garden, Worcester. Mr. Colin Walker of Stockport, England, and of the Haworthia Study Group, Cactus and Succulent Society of New South Wales, Australia.

Fig. 1. Haworthia margaritifera (L.) Haw., Karoo Garden, Worcester: three typical, large plants.

Fig. 2. Left: “H. poellnitziana Uitew.” 3m NW Drew. Centre: H. minima Haw., S Bredasdorp, small coastal form. Right: H. minima NE Riversdale, larger inland form.

Fig. 3. Left: H. margaritifera (L.) Haw., 8 m. SE of Drew. Centre: ‘H. poellnitziana’ 3 m. N.W. of Drew. Right: “H. poellnitziana” from the type locality at Drew. Note keel at leaf tips, typical of H. margaritifera x marginata hybrids.

Fig. 4. H. kingiana vPoelln., Great Brak.

Fig. 5. H. marginata (Lam.) Stearn, a plant from N. Ashton.

Fig. 6. “H. semiglabrata” Haw., a field hybrid H. margaritifera x marginata collected N. of Ashton.

Fig. 7. Diagramatic presentation of typical base and profile of flowers in the subgenera (a) Haworthia (top, (b) Hexangulares Uitew. (middle), and (c) Robustipedunculares Uitew. (bottom).

Printed in Cactus and Succulent Journal of Great Britain, 1972.

M. B. Bayer, Karoo Botanic Garden, Worcester, South Africa

Confusion in nomenclature has robbed an attractive and interesting genus of much of its charm and enticement to the collector. For the past few years considerable effort has been made at the Karoo Botanic Garden at Worcester, South Africa, into the investigation of Haworthia. It has been disturbing to find the extent to which current nomenclature is at variance with the natural groups as they are found in the field. Perhaps more disturbing is the difficulty which obviously lies in reducing the complex field relationships to an understandable and usable system of classification, Haworthia can clearly be divided into three subgenera on the basis of floral characters; these are the subgenus Haworthia in which the base of the floret is rounded-triangular and in which the outer three segments completely enclose the three inner ones, and the subgenera Hexangulares Uitewaal and Robustipedunculares  (Uitcw.) Bayer in which the floret base is rounded-hexangular (the florets stipitate in the former) with the outer floral segments separated by the midribs of the inner segments.

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Printed in Aloe 11:31 (1973).
M. B. Bayer, Karoo Botanic Garden, Worcester.

The fascination of haworthia lies in the shape, arrangement, compact neatness and marking of the leaves.  With nearly 170 named species and over 200 varieties, the genus is unfortunately very confused as far as the application of these names is concerned.  Many of the species originally described by Haworth and Baker have not been recognised since, while in recent times new species have been described with little or no reference to occurrence, distribution and variation of existing or related species.  Obstacles in the way of better classification and recognition of the species are many, and include insufficient information on basic morphology.  Secondly, whatever morphological differences there might be between species are often difficult to rationalise and describe, and may even be difficult to perceive with the naked eye anyway.  A third difficulty is the whole question of framing an adequate species concept, or for that matter, a concept of sections.   There is at present even an illogical trend to ‘lump’ the genera Astroloba, Poellnitzia and Chortolirion, into Haworthia, showing that concepts at that level have not reached reasonable finality.  The removal of genera can be applauded for its broadmindedness, if singular lack of appreciation of (a) the criteria by which they can be recognised, or (b) the reasons why they were erected in the first place.  Such an approach must naturally descend to species level, and at a time when the birth pangs of ‘splitting’ and consolidation have barely started, can only lead to a loss of information.

The writer’s experience of the naming of Haworthias and also of other succulent plants, suggests strongly that species descriptions based on broad external appearances are often very inadequate.  Growing conditions including the influence of soil types, temperature, water and light may have such a strong influence on plant growth as to completely nullify the written description, particularly where based on single specimens as has so often been the case.  The object of this article is to discuss the leaf arrangement in Haworthia and its relationship to the general appearance of the plants.  As in many plants, the leaves are produced consecutively at the growing point of the plant, and are consequently arranged in a single continuous spiral about the stem (the genetic spiral).  Thus Aloe polyphylla is by no means unique with its leaf spirals.  When the leaf bases are wide and enfold the stem it is much easier to observe this spiralisation, but when narrowly attached on a broad stem it may be more difficult to detect.  Generally the leaf bases are not continuous as they are in A. broomii where the leaves may be detached from the plant in a long continuous ribbon.  The leaves are produced at a fairly constant angle subtended from the stem and the result is similar to that obtained say when an orchard is planted with the trees at equal distances in and between the rows – i.e. secondary rows are visible when the orchard is viewed from a different angle.   These secondary rows are called parastichies.  The very obvious 3- and 5-tier arrangement of the leaves in the Haworthia section Trifariae and in Astroloba are the result of secondary spiralisation and have long been recognised in taxonomy.  Similarly Haworthia retusa was originally defined as quinquefarious and H. truncata has always been distinguished by its distichous leaf arrangement.

Generally it seems in Haworthia that the twenty-second leaf is again approximately superposed over the first after 8 complete revolutions of the genetic spiral (leaf-divergence (8.360)/21=137 degrees).  However, in the Trifariae only three leaves are clearly visible when the plant is viewed from below and these leaves form the bases of the three secondary spirals which characterise the group.  The leaves are arranged in three tiers with the leaf sequences 1—4—7—10;

2—5—8—11; 3—6—9—12 (i.e. three parastichies).  The classic example of this trifarious arrangement is H. viscosa where every third leaf is superposed approximately over the first.  In the quinquefarious (5-tiered) spiral, the leaf sequence is 1—6—11—16; 2—7—12—17; 3—8—13—18; 4-9—14—19; 5—10—15—20 (five parastichies as in Astroloba), and in the octafarious 8-tiered) spiral 1—9—17—25; 2—10—18—26; 3—11 etc.

In long-stemmed species particularly, it is possible to see simultaneously the arrangement of leaves in tri-, quinque- or octafarious series e.g. in H. reinwardtiii and H. coarctata.  In the short-stemmed, broad- and few-leaved species such as H. retusa or H. pilifera (now H. cooperi), only the lower series are visible, whereas in the acaulescent, many-leaved species, the higher series may appear.  It may seem that the angle of divergence of the leaves from one plant of a species to another is a constant one.  This is not true for the writer has seen for example a single plant of H. rnargaritifera now (H. pumila) with 8 perfect vertical rows indicating a leaf-angle of 135°.  Normally in this species the parastichies 5 and 8 are seen ascending in opposite directions.  In H. tuberculata (now H. scabra) the leaves appear randomly arranged at some localities whereas at others the plants are either trifarious or both the 3 and 5 parastichies are apparent.  In H. viscosa one would expect that to achieve three near vertical leaf tiers, that the angle of leaf divergence must be 120°.  Actually the angles prove to be only complementary, being often on the order 135°, 115°, 110° – to the point that they can be accurately measured.  Similarly in a plant of H. sordida the angles were measured at 180°, 95°, 85°.  Despite the fact that no one angle is measurably the same as the next, the plants still age to maintain an orderly progession of leaves.  In H. truncata, which is distichous (and really only approximately so), the two rows of leaves are actually the consequence of a spiral arrangement in which the leaf angle is near to 180°.

In H. limifolia the average leaf angle is in the vicinity of 160° but this is by no means constant as Diagram 1 of the variety ubomboensis will show.  Some leaf pairs are almost opposed at 180° and the youngest 7 leaves have an average divergence of 170°.  What is perhaps important is that two parastichies are prominent – the primary counter spirals with the leaf sequences 1—3—5—7; 2—4—6—8.  The impossibility of accurately estimating the central axis in the plant from which to measure the angles of divergence must be stressed.  By counting the number of leaves in rotational sequence until a leaf directly above the first is reached, an estimate can be made; thus the ninth leaf above the first in 3 revolutions is the consequence of (3.360)/8= 135 degrees divergence.  Spiral patterning is also related to stem diameter in proportion to leaf thickness and width.  If the stem diameter is great and leaf width small then the higher parastichies will appear.  The relation of stem length to number and size of leaves will also affect spirals.  In H. reinwardtiii and H. coarctata, a complex notorious for its many varieties and forms, the two species with their discrete distribution ranges are separable almost only by the fact that the ratio of number of leaves to stem length differs.  Thus in H. reinwardtii the leaves are more densely compressed on the stem, there are more leaves per unit stem length and the angle of ascent of the genetic spiral is approximately half that in H. coarctata.  Oddly enough the longest stems observed in a recent field study were H. reinwardtii:  27 cm and H. coaretata: 49 cm.  An associated variable is the ratio of stem diameter to leaf width…1:1,7 in H. coarctata, and 1:1,16 in H. reinvardtii.

Diagram 1 illustrates the leaf arrangement in a single plant of H. limfolia var ubomboensis showing the two counter spirals very clearly.  Diagram 2 illustrates the situation in which a uniform leaf angle of 135° presents 8 vertical parastichies, and also how variations of 1—4° alter the entire conformation in only 3 revolutions of the genetic spiral.  At 139° five parastichies are becoming prominent which will reach the vertical at 144°, whereas at 131 °three parastichies will be dominant and reaching vertical at 120°.  A 1°  increase in leaf divergence will result in an 8° displacement at the ninth leaf.

A.H.Church in a fascinating book… “On the relation of phyllotaxis to mechanical laws” (1904), explains that there is a fundamental constant which determines leaf arrangements and spiralisation.  He defines this as the “bulk-ratio”, which is the ratio of the diameter of the leaf buds to the diameter of the stem at the point at which they are joined to it.  In this light, raw dimensions (especially from single plants) can be seen as only a fractional contribution to species descriptions.  Where even normal standards of biometry have been ignored it is even more important to appeal for a more realistic use of measurements.  While proportionate dimensions of leaves and stem (ratios between leaf width, leaf thickness and stem diameter, for example) may help to better describe a species, it does not mean that the basic problem of defining the species will be solved.  In Haworthia the populations are so localised and often so variable that recourse will have to be made to even more refined methods before a satisfactory species concept will be obtained.  It is unlikely that “bulk-ratio” will help solve any problems at species level, but there is no doubt that it can contribute to deciding limits of sections, subgenera and even genera. In the case of the two very closely related species H. maughanii and H. truncata, it would be very interesting to know why the leaves of the former species “spiral” and why in H. truncata they remain distichous.

Diagram 1. Leaf arrangement in Haworthia limifolia var. ubomboensis showing the two primary counter spirals.

Diagram 2. Representation of leaves diverging at an angle of 135° in which 8 leaf tiers are vertical and a 4° increase or decrease in leaf divergence to show the appearance of 5 and 3 parastichies respectively.

Printed in Excelsa 4:17 (1974)

Introduction

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.

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Printed in Calandrimia, Succulent Publication, South Australia. :57 (1980).
M.B. Bayer, Worcester, South Africa

The attraction of Haworthias is their interesting diversity of leaf arrangement and form, as their flowers certainly do not attract attention.  My own interest in these plants owes itself certainly to my introduction to a plant then known as Haworthia chalwinii.  This is now know to be a variation of H coarctata in which the leaves are shorter and more closely adpressed to the stem than is normal.  Even now I am still impressed by the closely-incurved, tubercled leaves packed tightly above one another on a stem which may he up to 20 cm long.  Although I was scarcely 10 years old then, the memory of dense mats of H. cymbiformis on a riverine rock-face in the eastern Cape is still a strong one, but interest remained dominant until nearly twelve years later.  My father was stationed in the Natal Midlands and an uncle, who was a Health Inspector in the malaria areas of northern Natal, brought in an Haworthia from those parts.  J.R. Brown’s book…”Succulents for the Amateur” was one of my favourite books and by that stage would fall open at the section on Haworthias.  The picture of H. bolusii most impressed me and I felt that I knew enough then to recognise these plants from Natal as something new.  They seemed to me quite unlike H. limifolia which 1 knew from illustration, and I thought they should be described as a new species particularly to record the occurrence of the species in Natal.  Fortunately Dr. R.A. Dyer, Chief of the National Herbarium in Pretoria, persuaded me to be more moderate and the plant was eventually described as H. limifolia var gigantea.  Dr. Dyer also suggested that it would be wise to investigate the species in the field and so launched a 5,000 km wild-goose chase across northern Natal, Zululand and Swaziland.  The only direct success my companion and I had was in meeting Captain D.R. Keith at Stegi on the eastern border of Swaziland.  He directed us to the bottom of the Umbuluzi Valley where we found H. limifolia growing in vast quantity on the shaded dry forest floor On reflection I wonder why he did not direct us to his original farm Ravelston where the vars keithii and ubomboensis were found.   Although we found no other plants, we did find evidence of plants from as far afield as Paulpietersburg. Barberton, Gollell, Mozaan, Hluhluwe and even as far south as Stanger.  The plant is used by native witch-doctors and herbalists as a remedy for a variety of ailments and one recorded use is for the plants to be placed on the tops of the huts as a lightning deterrent.  Our collecting trip was thus highlighted by endless cross-examination of the rural blacks crying to locate where the plants could be found.  Neither of us had more than a smattering of the Zulu language and this was probably our main stumbling block to success.  On one occasion we were excitedly directed towards an unlikely looking hillside to find a police contingent waiting for us on our return to the vehicle.  Our ‘guide’ had taken us for communist agitators.  Another highlight was being marooned in the Umfolozi Game Reserve by flooded rivers.  Taking advantage of the forced respite, we thought we would explore the Reserve itself, famous as the then last resort of the white rhinoceros.  Our intrepid guide directed us off on a side road in search of the hotter-tempered black rhinoceros and we were soon axle-deep in thick black sticky mud.  The guide was most reluctant to get out of the car and help dig, push and curse while we tried to extract it from the mire.

In retrospect it is a pity that we did not make a more concerted effort to see H. limifolia in the field.  It is clearly a widespread species but in localised and isolated populations and subject to indiscriminate collecting.  I would particularly have liked to have seen the variety ubomboensis in the field, although each locality seems to produce a distinctive form.  After our exhaustive trip, the distant Cape became the obvious place for Haworthias.  My job held no prospects for getting there and a disaster to my collection in which all my labels were removed, persuaded me to abandon any further attempt at getting to know the genus better.  Although I had acquired a considerable number of plants, very few of them were authentic field collected plants and none were authoritatively named.  The few authentic specimens did not take readily to cultivation and I decided that, rather than collect for the compost heap, I would stop collecting.  Soon after this I moved to Johannesburg to be lost in a concrete jungle for four years until I was transferred to Cape Town.  At first I was reluctant to start collecting plants again and I confined myself to finding and seeing Haworthias in unfenced likely looking hillsides during travels through the karoid areas of the south-west Cape.  A visit to Kirstenbosch introduced me to the Fourcade/Long photographs, but more importantly to G.G. Smith’s collection and record.  G.G. Smith’s published work may not be of very much value, but the value of his herbarium material is inestimable.  The average collector (and it appears so for some would-be taxonomists too) can have no concept of the relationship of a herbarium specimen to a plant name or of the importance of proper herbarium record as a permanent, reliable record.

Among the first Haworthias I saw while in the Cape were plants of H. chloracantha near Great Brak. They were growing on a hot north-western slope with the tips of the leaves at ground level and betrayed only by a few old dry flower stalks that caught my eye (I cannot account for the change at this locality which is now heavily vegetated and quite unsuited to the haworthia).  This was followed by finding H. mirabilis ssp. badia at Napier growing in among small multi-coloured pebbles.  The leaves were the identical colour shades of yellow, white and orange as the pebbles and the plants were as difficult to see as any Lithops.  At one point I called my wife to come and locate three plants in a 15 cm (6”) square plot – she missed them, but pointed out two others which I hadn’t seen.  In those days we were still inexperienced and it was often a battle to find the plants.  I have since been back to the site where I first had the thrill and excitement of finding H. magnifica, to find that there were considerably more plants than I could have imagined on my first visit.

Several years earlier I had been corresponding with Roy Littlewood who was Horticulturist at the Karoo Botanic Garden.  Passing through Worcester one day I thought I would take the opportunity of ‘looking him up’ and meeting him personally.  It was a hot, dry day in February and I was singularly unimpressed with the Garden which had a country-wide reputation for the spring-flower display.  The Curator was Mr. F.J. Stayner who told me that Roy had died the previous year as the result of a heart-attack while collecting butterflies in the mountains nearby.  At that time Roy’s post was filled, but six months later was again vacant.  This time the old personal conflict between trying to forge a career and doing something which I was really interested in finally resolved itself.  I presented myself at Kirstenbosch and, in the absence of any other applicants, was lucky enough to be appointed to the post ‘Assistant to the Curator’ at the Karoo Garden.  Mr. Stayner was very good to me and I was allowed to devote my time to replanting and re-organising the extensive Haworthia collection which included a great many of Smith’s original plants.  The Curator of the Compton Herbarium at Kirstenbosch was also good enough to let me have all Smith’s papers to work on at Worcester.  It was immediately obvious that very little was known about the Haworthias in the Worcester/Robertson area and that all the available names bore very little relationship to the natural association of the plant populations in the area.  For one species growing indigenously in the garden and common throughout the area, there was no positive identification and about seven names to choose from.  Then there was Haworthia magaritifera (pumila) and all its variants as well as names such as H. semimargaritfera and H. papillosa to choose from too.  It was not surprising that as a collector in Natal I was being confused by the available literature.  A species such as H. reticulata had never been validly recorded from the field since it was described by Haworth in 1804 and yet here it was growing commonly in the area.  The problems involved in trying to ‘tie a name down’ for the species indigenous to the garden, now H. herbacea, proved that the identification by and from simple verbal description was going to be an insuperably difficult job.  Certainly comparison and separation of closely related species or populations on this basis would be virtually impossible, and this is a point which the collector should not forget.  There are many facets of the Haworthia charade which need to be appreciated by enthusiasts.  The first of these is that interest in the plants is associated with rivalry and antagonism.  The exchanges between Smith, Resende and Uitewaal were quite unnecessary and many other authors contributed to confusion and misunderstanding in the genus.  One common error which impressed me was the identification and matching of plants from illustrations or photographs.  So many times Smith, Long, Brown, or ‘A. N. Other’, would take one picture and match it with a comment like…”agrees with…” and so often this would be quite wrong.  Among the most blatant errors of this kind was the confusion of H. limifolia from northern Natal identified as H. margaritifera var. granata sub-var. polyphylla.  Many plants were described as varieties and forms of species which themselves had not been rediscovered or positively identified.  Plants from single populations were frequently classified down to varieties and sub-varieties of different species. In some cases species were being incorrectly identified at the level of sub-genus, and, for example, forms of H. fasciata were being confused with H. margaritifera.  Even Aloe aristata collected in the mountains of Natal had been collected and taken for an Haworthia and an herbarium specimen still bears the. manuscript name H. natalensis sp. nov.  It is more than likely that H. ferox was actually Aloe humilis.

When I first obtained Smith’s notes they included very few indications of how he intended to finally treat the genus.  There were of course all his published species and varieties and his final article “Views on the naming of Haworthias”.  In 1976 Kirstenbosch acquired many more papers from the estate of G.G. Smith through the kind agency of Dr. M. Courtenay-Latimer who had done so much of Smith’s paper work.  These papers contain Smith’s assessment of his collection and it is interesting to note just what he had in mind.  Firstly it is clear that he had no species concept whatever and that he had an immense hoard of new species and varieties in mind.  In the ‘retusae’ he had nine varieties of H. nitidula (which is a synonym of H. mirabilis) drawn from three different species.  He had designated two varieties of H. pygmaea, fifteen varieties of H. retusa, a variety of H. rossouwii (H. mirabilis), three varieties of H. dekenahii, three completely new species and several sub-varieties.  In H. viscosa he had earmarked seven new species, and in H. reinwardtii he had a further four varieties for description.  No one should underestimate Smith’s observations and the detail with which he compared his plants.  Each description was preceded by a point-for-point check-list of characters and he insisted in growing all his plants for several years before coming to conclusions.  Smith had virtually set himself several life-times’ work to classify and describe each variant he encountered.  Unfortunately this kind of single-minded intensity still persists and there are still collectors following the same path, but with plants which do not even have the merit of field origin.  It is not in the least surprising to find that there was so much difference of opinion concerning identification.  For many names there was no type plant of any kind and it is really ridiculous to find controversy where neither party had any basis for argument.  Unless there is some reference point for a name and unless there is some appreciation of what a name actually stands for, argument as to identification is totally futile.  It is tragi-comic to find collectors who still insist on using the nomenclature abandoned by Smith and von Poellnitz.  In most cases this excludes about 95% of the natural populations and leaves the remaining 5% in a curious and impossible tangle.  It should be remembered that most plants now in cultivation, particularly overseas, probably are derived from plants propagated during the Triebner era or earlier.  These are mostly species which propagate vegetatively and are difficult to kill with kindness.  Possibly more than half the actual existing species are not even in general cultivation.

During my first three years at the Karoo Garden I spent much of my time following up G.G. Smith’s locality records.  One interesting trip involved following a diarised record of the collector Otzen through the south-western Cape.  Several localities no longer existed, but it was an impressionable experience to come again upon localities which he had visited 40 years before.  One of these involved the locality for H. otzenii (=H. mutica), and it was clear that the origin of this species had been confused.  I met many most interesting and helpful people figured in the records and literature such as Mr. A.J. Joubert, a schoolteacher now retired, at Ladismith; and Mr. J.J. Dekenah at Riversdale who must have been on nodding acquaintance with every Haworthia plant within a 50 km radius of the own.  I met Mrs. L. Lategan at Oudtshoorn to try to extract cite veiled mystery behind the name ‘H. smitii’, and Mrs. Baldii (nee Taute) who verified the locality for her mother’s find H. tauteae.  Mr. C.J. Payne still lives at McGregor and is a complete character in his own right.  He is a bachelor, the local church organist and the possessor of one of the greatest collections of South African sheet-music.  He has lived all his life in this remarkable backwoods town and still has a derelict collection of Aloes dating back from C.W. Reynolds’ pre-war collecting activities.

Having seen all the known species of Haworthia in the field, each name conjures up related memories.  The setting has varied from H. chlorocantha in the middle of the town of Mossel Bay (now a concrete jungle), or H. unicolor in the caravan park at Barrydale, to H. wittebergensis in the solitude and grandeur of the mountains.  H. marumiana was a complete mystery for many years until Bruce Bursey introduced me to Cameron McMaster at Cathcart.  Cameron showed me a plant which he had collected along a remote road south of Tarkastad in the northeastern Cape.  I arrived at the locality late at night and had to spend a wretchedly uncomfortable night contorted in the cab of the small truck I was driving.  However, I was rewarded by finding the plants the next morning and so could confirm that the species is in fact from the mountains of the Great Karoo and north-east Cape, and not the little Karoo as stated. H. lepida also gave a lot of trouble, although the locality was recorded fairly accurately by G.G. Smith.  We spent two days in the hot dry dusty Fish River valley scouring the steep brush-covered hillsides and had to conclude that the population no longer existed.  This was probably the only occasion on which I could not confirm one of Smith’s records and we had to content ourselves with a population a few miles further on.  However, Smith did make a serious error in the case of H. baccata.  He described this species without seeing it in the field and it is practically certain that it never was collected from Stutterheim as recorded.

I shall never forget the two weeks spent with Dan Timm in the Grahamstown area looking for H, coarctata and H. reinwardtii.  We particularly visited the farm Hopewell’, which was a Smith family farm, and where G.G. Smith had found H. musculina, H. fulva, H. greenii var. silvicola and also identified H. coarctata, H. chalwinii and H. reinwardtii.  After repeated visits and hours and hours of scrambling, stumbling and falling through dense thorny thicket we could only conclude that there was one species on the farm and not even as variable as all Smith’s identifications suggested.  It is the sort of place that Mr. J.W. Dodson, or the New South Wales Study Group would really appreciate.  We also looked for Smith’s varieties of H. angustifolia and it took considerable detective work and eventually pure luck to find the plants.  We found the variety paucifolia only by virtue of the fact that the plants were in flower, as otherwise they are completely hidden among dense thickets of grass-like Restio.

It was G.J. Payne who caused me the most collecting grief.  Late one afternoon following two very strenuous days in the undulating Robertson-Bonnievale area, I passed through McGregor and called in the see Mr. Payne.  He said that he had once collected an Haworthia at a place called ‘Die Galg’ in the nearby mountains, and we duly set off to look for it.  ‘Die Galg’ (in English ‘The gallows’) is a very impressive incomplete pass or cut, high up in the Riviersonderend Mountains.  It is the start of a long, deep valley which runs southwards to Greyton and the Riviersonerend River about 25 km away.  During the War years, Italian prisoners had been put to work making a roadway through the valley, starting at Die Galg at the top.  It was an impossible task and the road was never remotely finished.  It petered out completely after about one kilometre, over a steep-sided valley with the deep gorge winding away in the distance to the south.  Mr. Payne said that he would stay and wait as he did not feel fit enough to accompany me and in any case the plants were not far and the place was easy to find.  Previous experience had shown tine and again that collectors (Payne included) had seldom ventured far from the beaten track and so despite my tiredness, I climbed down into the gorge.  After miles of rough, narrow, often indiscernible track I did eventually find the plants, but the light was already fading as I turned to go back.  I have seldom managed so good a night’s sleep in a room of a country hotel, above the pub on a Friday night.

Very long distances were usually involved in collecting trips but the most hazardous eventually turned out to be a local search.  Smith had an odd record of plants collected ‘at 4,000 feet, Audenberg Peak’.  The Karoo Garden is at 1,000 feet and thus the locality was somewhere high on a series of four tooth-like peaks a few miles north of the garden.  The original collector of Smith’s plants was Miss Elsie Esterhuyzen, an ageless, spry queen of the Western Cape mountains who is still associated with the Bolus herbarium at the University of Cape Town.  It took time, co-ordination and organisation to get a party together for the climb and it was a disappointment to wake up in the morning to rain and mist.  Undaunted, Elsie led us on what, with anybody else, would have been a completely foolhardy venture.  The climb was a very steep one and at times we could only guess where the almost vertical rock sheets ended in the swirling mist below.  In most places there was no track or path at all because even the local mountain club members very seldom ventured there.  However, Elsie led us unhesitatingly right to the plants – no mean achievement when one considers that she had been there once thirty-five years before.  It was a bit of an anti-climax to later find the same variant of H. herbacea (H. maculata) within fifty metres of the National Highway in the Hex River Pass at an altitude of 1,000 feet.  It is this kind of record which will eventually pave the way for a real understanding of the complexity in Haworthia.

After contemplating the difficulties of Haworthia taxonomy, I pushed the thought of a book completely into the background.  Although they have such fascinating forms they are almost devoid of characters by which they can be identified by eye.  The species are separated by nuances of shape and colour and often there are no clear boundaries within whole groups such as in the retusae.  The decision to produce a booklet was finally undertaken simply to record a workable assessment arrived at after considerable involvement with the group.  The original title of the booklet was “Haworthia – an Illustrated Check-list”’ and it is intended solely as a guide to the nomenclature and literature in the genus, and to streamline the nomenclature to a more relevant and workable one.  Names are not for collectors, but provide the basis on which information is collected and collated about our environment.  No matter how many books are written on Haworthia, however profusely illustrated, the collector will never at this point in time be able to identify all the plants he encounters with complete certainty.  He will have to concede that each species name covers a variable group of plants.  In some cases the species are not absolute and technically should perhaps not even be regarded as species.  John Pilbeam of England is presently completing a more comprehensive book on Haworthia and this will indeed give the collector something to which he may look forward.  Perhaps we can look forward to an era where a genuine concerted effort is made towards propagating and distributing those species which have so far been rare in cultivation.

THE CAPE FLORA AND THE KAROO
— A winter rainfall biome versus a fynbos biome!
by M. B. Bayer, Curator, Karoo Botanic Garden, Worcester
Veld & Flora March 1984

The humorist Groucho Marx when once propositioned said “for that you can include me out!” That is just how someone living in the Cape not within eyeshot distance of an erica, a protea or a restio, must feel — included out. Naturally one wants to be in on the show and Nordenstam’s¹ statement that there is a “tendency to particularise the Cape flora” is a comforting one for those out in the cold.

Several recent papers on the Cape flora (Goldblatt², Taylor^{3, 4} and Oliver, Linder and Rourke⁵) strengthen the exclusiveness of the club, and currently Cape flora and fynbos (sensu Taylor⁶) seem to be synonymous. Karroid species (non fynbos sensu stricto) are only called in when necessary to boost the numbers of species in, and stress the richness of, the Cape flora.

Geological pattern Peter Goldblatt points out that the correlation between the Cape floristic region and mediterranean climate is a loose one. But it is his concession that the Cape region follows a geological rather than a climatic pattern which is more interesting. This is not only because of the obvious relationship between Table Mountain sandstone and fynbos, but because geological considerations seem to have been lost in the recognition of the Karoo-

Namib region. This phytogeographic region extends from Angola in the north, to the south-eastern Cape and is the effective inland boundary of the Cape region. White’s Karoo-Namib² covers the Kalahari sands, basement granites, bushveld granites and, predominantly, shales the Karoo system. and tillites of The paper by Oliver et al is a cruel shot in the eye, because in setting out to reappraise the boundaries of the Cape flora, only species typical of fynbos are used. A predetermined result.

Fynbos formation in new perspective There is no denying that fynbos is a “separate plant formation distinct floristically and physiognomically from the formations of the Republic”³ but it is time that its geological associations are brought into proper perspective. Oliver et al write of “tongues of vegetation” … rendering exact and simple definition of their (fynbos, Karoo and evergreen forest) boundaries very difficult. My contention is that such a definition is difficult because geology, and hence soil, overrides all the other ecological factors which operate to determine vegetation.

Winter rainfall should have been the natural choice in selecting an agent responsible for the uniqueness of fynbos, and one must ask why this is not done. Goldblatt skirts the issue and simply bases his Cape flora “solidly” on Acocks⁷, and includes non-fynbos vegetation types for practical reasons — in order to draw a rigid line about the Cape flora region. The area under winter rainfall is by-passed because it and the fynbos area do not coincide. Instead, there is a fairly abrupt end to the fynbos which coincides with the limits of the Table Mountain and Witteberg sandstones.

Currently the winter rainfall area is fairly well-defined by Poynton⁸ as extending in an arc from the mouth of the Orange River to Cape Agulhas. Poynton does not define “winter rainfall” but it is assumed to be where 60% or more of annual rainfall occurs in the winter. The zone of uniform annual rainfall parallels that of winter rainfall in the north, but widens southward and eventually ends between Port Elizabeth and East London. If that is the present situation, then what of the past?

Menace of an expanding Karoo Nature lovers and conservationists are concerned by shrinkage and loss of fynbos — and agriculturists by the north-westerly migration of the Karoo. Acocks¹⁰ paints a grim picture of the Karoo and semi-desert invading the rich grasslands of the Orange Free State and Eastern Cape. Although shrinkage of fynbos and expansion of the Karoo are not directly linked (the first is attributed to “mechanical” destruction, and the second to pastoral land use), there may be a connection. The future will become history and so then, what of the past?

The results of palynological research⁹ supported by other disciplines, shed a whole new light on the real Cape flora. It appears that as recently as 12-15 000 years ago, the world was experiencing a minor ice-age. During this time the system of mediterranean climate was situated northwards by as much as 6° latitude. This means that the northern limits of winter rainfall would have been in the north of South West Africa instead of at the mouth of the Orange River as it is now. Cyclonic winter rainfall would havebeen reaching across the southern Kalahari, across the Orange Free State and deep into Transvaal.

Shifting rainfall regimes Acocks gives a map which depicts the extent of Karoo elements, and these fit beautifully into the conceptof an extended winter rainfall region. Now it begins to make sense. The Cape flora is not just fynbos— it is a plant formation which coincides with the expansion and contraction of winter rainfall and all associated phenomena. As the winter rainfall zone has movedsouthwards, so has the Karoo shrunk accordingly. The flora of the Kalahari highveld, Afro-montane and Tongaland-Pondoland regions have advanced along the face of the retreating Karoo and advancing summer rainfall regime.

Acocks’ hypothesis of an expanding desert is true in the sense that grazing pressure particularly on summer rainfall grasses, has reversed the process. Non-palatable Karoo species have regained lost ground. Probably only because summer rainfall species competition has been reduced. Remotely perhaps because of a climatic swing back to a winter rainfall regime (heralded by the current devastating summer drought) or artificial aridification as a result of reduced ground cover.

With the possibility now established that Karoo is also Cape flora, a whole host of plant species can waltz into the limelight and take a bow. A winter rainfall biome can now be recognized within which other factors such as geology, altitude, latitude and longitude can operate. However, it is still important to explain adequately the vast difference in species endemism which exists between the north-west and the south-east areas of this winter rainfall biome.

Thoday’s 1925 map of drought severity in NW Cape This is remarkably easy because as long ago as 1925 D. Thoday¹⁰ in a study of Passerina presented a telling map illustrating the severity and incidence of drought. This shows that the north-western Cape (Namaqualand and Bushmanland) has to contend with extremely severe summer drought. Thoday’s map can be exterpolated to a glacial age with little imagination. Coupled with seasonality of rainfall, and history of climatic shift, we now have a scenario in which the Karoo can be properly related to fynbos. It can be suggested that high species endemism in the north west is due to geological and climatic extremes. Low endemism (?) in the Eastern Cape is because of relative equability of climate (rainfall) during glacial and post-glacial shifts.¹¹

The fynbos derives its special place because of geology and sustained high winter rainfall, which impose further isolating mechanisms over location at the tip of a continent. The whole purpose of this little exercise is not only to gain access for a Karoo lover into a fynbos club. It is to find a foothold for a feeling that the Cape flora is a very ancient one — the concept of only fynbos representing a Cape flora reduces our capacity to observe and understand what we have and how we are to keep it. Fynbos is not an element which had advanced and retreated like an army. There has been a retreat with a rising sea level and constricting coastline as the glacial age passed, and there has been some change along the interface between summer rainfall and winter rainfall. But the fynbos has been reasonably secure on its geological base, and so has the core of species comprising the Karoo.

Stronger urge to conserve The endemnicity and distribution of many species such as in the genera Aloe, Commiphora, Pachypodium, Tylecodon, Adromischus, Crassula, Conopytum (and most of the mesem genera), Euphorbia, Asclepiadaceae, Geraniaceae and Oxalidaceae all support the wider concept of the Cape flora as a winter rainfall biome. This endemism suggests a permanence beyond minor climatic change (eg. Aloe can perhaps be argued back to the time of continental drift 140 000 000 years ago). Such permanence suggests that we need a still broader and stronger urge to conserve — or we will plough, bulldoze and trample away the florally greater equivalent of the great library at Alexandria.

REFERENCES

1. B. Nordenstam: Phytogeography of the genus Euryops (Compositae). A contribution to the phytogeography of Southern Africa. Opera Botanica 23; 1-79 (1969).

2. P. Goldblatt: An analysis of the flora of Southern Africa: its characteristics, relationships and origins. Ann. Missouri Bot. Garden 65; 369 436 (1978).

3. H. C. Taylor: Phytogeography of fynbos 13; 231-235 (1980).

4. – Is fynbos the natural climax vegetation of the south-western Cape Province of South Africa, in proceedings of the International Symposium on Vegetation Science, ed. A Schwabe-Braun, Cramer, Vaduz, p 385-391 (1981).

5. E. G. H. Oliver, W. P. Linder and J. P. Rourke: Geographical distribution of present-day Cape taxa and their phytogeographical significance. Bothalia (in press).

6. H. C. Taylor: Capensis in biogeography and ecology of Southern Africa, ed W. T. A. Werger, The Hague, p 171-229 (1978).

7. J. P. H. Acocks: Veld types of South Africa. Mem. Bot. Surv. S. Africa 28: 1-192 Govt. Printer Pretoria (1953).

8. R. J. Poynton: A silvicultural map of Southern Africa. South African Journal of Science 67: 58-60 (1971).

9. E. M. van Zinderen Bakker: The evolution of late-quartemary paleoclimates of Southern Africa. Palaeoecology of Africa 9, Balkema,Cap e Town, p 160-202 (1977).

10. D. Thoday: The geographical distribution and ecology of Passerina. Ann. Botany 39: 175-208 (1925).

11. R. M. Cowling: Patterns of plant endemism in the south eastern Cape. The Naturalist 27: 17-36 (1982).

Printed in Excelsa 12:91 (1986)

Haworthia is a genus plagued by confusion of one kind or another and it seems now impossible to write about these plants without casting doubts on someone’s integrity or sanity.  The problem in the genus is not simply that there are very few herbarium specimens, or adequate descriptions and illustrations by which the various species can be typified. The various elements in the field are so continuously variable that it is difficult to decide where one species begins and another ends – but not so difficult.  There is some straightforward confusion as in the case of Haworthia margaritifera (L.)Haw. where Wijnands shows that H. pumila (L.)Duval is incorrect.  (Excuse my nomenclature – but this means it is incorrect for the species to which Duval attached the name [H. herbacea] – it is correct for the species to which Scott attached the name).

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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.

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