Taxonomic studies in the Aizoaceae from South Africa : three new species and some new combinations

Two new species o f Brownanthus, B glareicola Klak and B fratem us Klak and one new species of Scopelogena, S. bruynsii Klak are described. S. gracilis L.Bolus is reduced to synonymy under S. verruculata (L.) L Bolus. Three new com­ binations are made: Antimima excedens (L.Bolus) Klak. Erepsia dunensis (Sond.) Klak and Hammeria meleagris (L.Bolus) Klak and full synonomy is given Lampranthus maximilianii (Schltr. & A.Berger) L Bolus is transferred back to Braunsia maximilianii (Schltr. & A Berger) Schwantes and the identity of Ruschia polita L Bolus is discussed. The taxonomic posi­ tion of Mesembryanthemum purpureostylum L.Bolus is clarified.


B rau n sia Schwantes
Braunsia is a small genus of about four or five species which is thought to be related to the Lampranthus group (Hartmann 1991).The echinate seeds and leaves that are fused for a quarter to half of their length, with white, cartilagenous margins, were so far considered to be the main characteristics o f the genus.
The lack of echinate seeds in one of the species, Braunsia maxim ilianii, prompted L. Bolus (1965) to place it rather in Lampranthus N.E.Br.. which never has echinate seeds.This view stood in contrast to the earlier opinion of N.E.Brown (1929).He considered the pres Brown.Apart from the morphology of the flowers and leaves, which are typical for Braunsia, the morphology of the capsules excludes this species from Lampranthus.
In contrast to Lampranthus, where the expanding keels always diverge from the base, those of Braunsia are par allel for most of their length and only diverge towards the tips.In addition, the covering m em branes in Lampranthus are always complete and more or less firm, often with additional closing devices below the covering membranes.In Braunsia the covering membranes only cover the locules partly, are fairly flexible and do not have any additional closing devices.The capsules of Lampranthus maximilianii were found to be typical of species of Braunsia in all these details.Therefore the older name.Braunsia maximilianii is re-instated here.

B row n an th u s Schwantes
Brownanthus is one of 11 genera placed in the sub family Mesembryanthemoideae. Apart from Psilocaulon N.E.Br., Aptenia N.E.Br.and Aspazoma N.E.Br., it is one of the few genera in the Aizoaceae in which stem succu lence has developed (Bittrich 1986).At present ten species are recognised (Pierce & Gerbaulet 1997).The main characteristics of the genus are that the sepals re main upright throughout anthesis, the white or creamcoloured flowers never possess any filamentous staminodes and the lower part of the capsule is shallowly bowl-shaped (Ihlenfeldt & Bittrich 1985).Recent explora tion in Western Cape has brought two new species to light both of which can unambiguously be placed in Brownanthus.
Distribution and ecology: Bredasdorp and Swellendam Districts (Figure 2); on quartz patches overlaying clay or on gravelly shale slopes; winter rainfall up to 400 mm.The habit, floral morphology and, in particular, the epidermal features o f the stem of B. fraternus (Figure 1C) are very similar to those of B. corallinus (Thunb.)Ihlenf.& Bittrich (Figure IB), but the former may be dis tinguished by its less papillate leaves (Figure 1G).The most conspicuous difference lies in the seeds where there is a hilar bulge in B. fraternus (Figure 1H), which is absent in B. corallinus.

B.
fraternus is known from three localities between Swellendam and Bredasdorp.where it appears to be under threat from agricultural activities.This is much further south than any other Brownanthus and it is the only species of Brownanthus which grows on the coastal plains south of the Langeberg.Dwarf, erect shrub up to 170 mm high, 250 mm wide.Stems articulated, green, succulent, becoming slightly woody with age towards bases; internodes cylindrical, 3.5-5.5 x 3.5-4.5 mm, epidermal bladder cells xero morphic with hair-like extensions (Figure 1A).Leaves deciduous, up to 3-5 mm long, concave above, convex below, overlapping at bases, epidermal bladder cells mesomorphic without hair-like extensions (Figure IE).Calyx with 5 lobes; lobes shortly connate and erect 1 \ ^-4-rV'T T \ 5 j|   The material upon which the description is based, comes from a locality south of Vanrhynsdorp, where the plants were first noticed by A. Ellis and P. Desmet in 1996.The species had previously been misidentified as Brownanthus corallinus and grows together with it in one of the known localities.The new species is distinct ly smaller and more compact in growth than B. coralli nus and the older stems are only slightly woody towards their bases.It also differs from B. corallinus (Figure IB) by the hair-like epidermal cells which cover the stems (Figure 1A).Furthermore, the bladder cell idioblasts of the leaves are noticeably more reduced in size compared to the ones in B. corallinus and the bases of young leaves overlap, which is never found in B. corallinus (Figure IE. F).In addition, the leaves in B. corallinus are subcylindrical, whereas in B. glareicola they are convex below and concave above.Further differences may be found in the seeds.These have a conspicuous crest in B. glareicola, which is not known for any other species of Brownanthus (Figure 1D).W hereas B. corallinus is known from numerous local ities over a distance of about 250 km in Namaqualand, B. glareicola appears to be much rarer and is known from only two localities in the southern Knersvlakte (Figure 2).In all of these it grows on patches of flat to gently sloping quartz gravel.
E rep sia N.E.Br.
Erepsia was revised by Liede (1989).Characteristics separating it from the closely allied genus Lampranthus N.E.Br., are the triquetrous leaves with tough epidermis and the presence of a hypanthium.Liede (1989) subdi vided the genus into four sections, three of which share flowers with vertical hypanthium walls and leaves usual ly less than 5 mm diam.The remaining section, Crassifo lia e , consists of seven species in which the walls of the hypanthium are sloped outwards and the leaves are most ly fairly thick (5-10 mm diam.).
Recently, plants of the very rare Lampranthus dunensis were rediscovered on the Cape Flats.This species was described as Mesembryanthemum dunense by Sonder (1862).In Jacobsen (1960), L. Bolus moved it to Lam pranthus and placed it in the informal section Reptantes.
An examination of the flowers of this material showed that they differ from those found in all species of Lampranthus, in that they possess a conspicuous, out wardly sloped hypanthium.In addition, the broad, tri quetrous leaves with tough epidermis are typical of species placed in Erepsia section Crassifoliae.This fea ture, together with the noticable triquetrous leaves suggest that L. dunensis belongs in Erepsia.The leaves are 4-6 mm broad and fall within the limits included by Liede

H am m eria P.M.Burgoyne
Hammeria was recently established for two species from the Ceres Karoo.The type of the genus is Ham meria salteri (L.Bolus) P.M.Burgoyne, with Ruschia salteri L.Bolus as its basionym (Burgoyne et al. 1998).Even more recently Hartmann (1998b) published a new name, Lampranthus tanquanus H.E.K.Hartmann, based on the same type, without reference to the earlier publication of Burgoyne et al. (1998).
The absence of closing bodies and the presence of valve wings were the reasons for excluding Ruschia salteri from Ruschia.Burgoyne et al. (1998) suggested morphological similarities to Antimima, Cheiridopsis and Chasmatophyllum, but were unable to place R. salteri into any of the existing genera.Hartmann (1998b) noted correctly that the fruits resembled those of the Titanopsis type, with thin, flexible, covering membranes bending down into the empty locules, and almost com plete covering membranes.In addition, the locules are shallow, so that the lower part of the capsule is bowl shaped.In contrast, fruits of Lampranthus are always deep, ± funnel-shaped, with firm, complete covering membranes and often additional closing devices below the covering membranes.It is therefore not possible for this species to remain in Lampranthus.From the capsule morphology, it appears more likely that closer relation ships may be found with species placed in the Titanopsis or the Stomatium group.A closer study of this complex is needed before it can be decided whether Hammeria may be included in one of the existing genera or indeed deserves generic status.
However, it has so far been overlooked that the same species was named several times by L. Bolus.Since one of these names predates R. salteri, a new combination and synonomy are necessary.

Scopelogena L.Bolus
Mesembryanthemum verruculatum was already known to Linnaeus and had been introduced to England in the early 1730's (Dillenius 1732).L. Bolus later placed this species in Lampranthus (Bolus 1950).The plant, however, could be separated from Lampranthus by the apparent lack of valve wings and the fact that the cap sules do not close completely once they have opened.On the other hand it differs from Ruschia by the absence of closing bodies and by the yellow colour of the petals.These reasons prompted L. Bolus to establish a new genus, Scopelogena, in 1962 for this species.At the same time she described a second species of Scopelogena, S. gracilis L. Bolus (1962).

S.
verruculata is known only from the Cape Peninsula, whereas S. gracilis was described from Grootvadersbosch, east of Swellendam.The latter was said to differ from S. verruculata by the more slender, sometimes obtusely keeled, often laterally compressed leaves, with the capsule obconical inside and not angled.Newly collected material from west and south of Swellendam has shown that none of these characters consistently separate S. verruculata from S. gracilis and that they are conspecific.S. verrucu lata is distributed from Cape Town sporadically eastwards to Herbertsdale, usually occurring on exposed, locally arid, sandstone outcrops.
These investigations have also shown that, contrary to previous descriptions (Bolus 1962), newly ripened cap sules which were opened for the first time possessed very narrow, 'seam -like' valve wings.In most of the old cap sules this character is no longer visible and this might explain the fact that it was not mentioned in previous descriptions.
Recent exploration has brought to light a second species, which occurs further north of the distribution area of S. verruculata.This is now described.Despite the large size of the plant, this species has so far been over looked by most collectors.It is named after P.V. Bruyns, who was the first to notice it in Namaqualand in 1992.Woody shrub up to 0.3 m high, 2 m wide, with stout, erect or spreading, grey to brown stems.Leaves crowd ed, shortly connate, incurved, erect, 3-angled to cylindri cal, obtuse, up to 16-50 x 3-5 mm, shortly mucronate, very soft, grass green to grey or sometimes reddish.Calyx of 5 subequal lobes.Flowers in much-branched inflorescence; pedicels 4-15 mm long; bracts up to 15 x 15 mm.Staminodes: petaloid staminodes in 1 or 2 series, yellow rarely white; no filamentous staminodes observ ed.Stamens erect, outer stamens dorsally papillate up to middle, inner ventrally papillate at middle; anthers and filaments yellow.Nectaries in crenulate ring.Ovary semi-inferior; stigmas filiform, longer than stamens; placentation parietal.Fruit a hygrochastic capsule, not fully closing again once opened, ochre, relatively soft, not woody, 5-locular, 5 -9 mm diam., top convex, lower part deep, funnel-shaped, with very narrow valve wings when young, covering membranes incomplete to almost com plete, with inconspicuous ridge below covering mem brane, expanding keels diverging, without closing body.Seeds dark brown, obovate, tuberculate, 1.1-1.2mm long.Flowering tim e: September-October.

Distribution and ecology:
Cape Peninsula to Riversdale (Figure 3); on sandstone cliffs, with winter rainfall of 300-600 mm annually.

S.
verruculata and S. bruynsii are morphologically very similar and there appears to be no doubt that this new species belongs in Scopelogena.This is dispite the fact that in the new species the capsules open and close repeatedly.Consequently one of the main distinctions of Scopelogena (that the capsules remain open) falls away.Similar variability in this feature is also found in species of Aridaria (Gerbaulet 1996).The flowers of S. bruynsii may be yellow, pink or salmon-pink.S. verruculata has predominantly yellow or rarely white flowers.

5.
bruynsii is found over a wide area, from Nuwerus to Clanwilliam and eastwards to the Ceres Karoo.The plants are always found growing on low sandstone cliffs.
The character combinations present in Scopelogena do not suggest clear affinities to any other genus in the Ruschiodeae and, consequently the relationships of Sco pelogena need further study.

The correct identity of Mesembryanthemum purpureostylum L.Bolus
In recent literature, much confusion has arisen over the correct identity of Mesembryanthemum purpureostylum L.Bolus.The type was based on a collection from Bonnievale.L. Bolus later included this name in the syn onymy of Ruschia forficata (L.) L. Bolus. Bruyns (1997) was the first to notice that in fact two different species were involved: R. forficata (L.) L.Bolus was found to be a synonym of Erepsia forficata (L.) Schwantes.Based on the presence of closing bodies and the absence of valve wings, Bruyns (1997) transferred M. purpureostylum to Ruschia, but, shortly afterwards, it was moved to Acrodon by Burgoyne (1998).In the same year, Hartmann (1998b) published a new combination in Cerochlamys based on the type of M. purpureostylum L.Bolus, how ever, without reference to any of these recent publica tions.
The absence of a capsule on the type poses some dif ficulties for the correct position of this species.However, a watercolour painting of the type specimen exists in the Bolus Herbarium (by M. Page) and this shows the habit, as well as the leaves and flowers.From this it is obvious that the flowers have their filamentous staminodes and stamens collected into a central cone, with the filamen tous staminodes overtopping the stamens and partly con cealing them.This arrangement is found in numerous other genera such as Ruschia and Antimima, but in none of the other species of Cerochlamys.In Cerochlamys the filamentous staminodes are loosely arranged in a cylin der around the stamens, sometimes with the outer ones spreading horizontally (Hartmann 1998b: 51, t. 16, 18, 20).The flower of Acrodon purpureostylus shown by Burgoyne matches that of the type.Hartmann, on the other hand, makes no mention of this typical cone flower.
In addition, Hartmann did not find any closing bodies in the capsules of the two collections which she cited.Both Bruyns and Burgoyne mention the presence of clos ing bodies in their collections.Both B ruyns' and Burgoyne's collections agree with the illustration of the type in all details of habit, leaves and flowers.It can therefore only be deduced that Hartmann must have based her conclusions on misidentified material.From the characteristics found to be typical of Acrodon (Hartmann 1996), Burgoyne (1998) showed con clusively that the species should be placed in Acrodon and no reasons have been put forward to alter this.A complete list of synonyms is given below.
A crodon p u rp u reo sty lu s (L.Bolus) P.M. Burgoyne in Aloe 35: 60 (1998).The identity of Ruschia polita L.Bolus Until now much uncertainty has existed about the identity of Ruschia polita L.Bolus, which was described in 1932.The type specimen was collected by G. Nel at Touws River in April 1930.Bolus was uncertain whether this species belonged in Ruschia, as she placed a ques tion mark next to the genus in her text.The absence of fruits on the type sheet may have added to the confusion.Annotations on the type sheet suggest that it belongs either in Corpuscularia or Antimima.
However, species placed in Corpuscularia are charac terised by a peculiar which is made up of tightly packed, dome-shaped epidermal bladder-cells.The surface of R. polita, on the other hand, consists of flattened cells and is completely smooth.In addition, species of Corpuscularia have so far only been recorded from a fairly small area around Port Elizabeth, in the Eastern Cape.Thus, the difference in epidermal mor phology and the very disjunct distribution would suggest that the type specimen of Ruschia polita is unlikely to belong to Corpuscularia.
Exclusion of this species from Antimima and Ruschia is more difficult since the type lacks any fruits.Nevertheless, since Bolus did not mention the clustering of filamentous staminodes into a dense cone, it seems unlikely that it is either a species of Antimima or of Ruschia.
A notable feature of the type specimen is, however, its sharply keeled, thick leaves with cartilaginous margins.This is typical of species placed in Braunsia.The description of Braunsia geminata matches very closely that of Ruschia polita.both with respect to the morphol ogy of the leaves as well as the flowers.In addition, the distribution of B. geminata extends from the Ceres Karoo to Prince Albert and the Little Karoo and so the type locality of R. polita falls within this area.Thus it is reasonable to conclude that R. polita is conspecific with B. geminata.
B raunsia gem inata (Haw.)L. Bolus in Journal of South African Botany 33: 306 (1967).In recent years, at least among urban gardeners, the popularity of agavaceous taxa is seemingly on the increase.The plants are being used as inexpensive, per manent barriers to ward off intruders.With their formid able spines, large and compact habit, drought resistance and aggressive growing capability, they are ideally suit ed for this purpose.With the abandonment of habitations, these hardy agaves can persist without human interven tion and subsequently become adventive aliens (Kloot 1987) in the local flora.One such species, Agave decipiens Baker was recently recorded in South Africa (Smith & Steyn 1999a).This paper deals with a comparable alien, namely A. vivipara L. var.vivipara.

VARIOUS AUTHORS AGAVACEAE
Agave vivipara.often known by one of its synonyms, A. angustifolia Haw., is a variable species native to cen tral America (Gentry 1982;Forster 1992).It is thought that the species was the wild ancestor of henequen (A.fourcroydes Lem.), a cultivated species known world wide for the high quality o f its fibres (Colunga-GarciaMari'n & May-Pat 1993;Colunga-Garci'aMarin et al. 1999).Mr Bernard Ulrich (Pforzheim.Germany) has in turn suggested to the second author that A. vivipara is possibly a selected form of the widely cultivated A. sisalana Perrine, source of sisal hemp.Currently, six varieties, including the typical variety, and two cultivars are recognised in A. vivipara (Forster 1992).According to Gentry (1982), this species complex has the most wide-ranging distribution of agaves in North America (for a list of exsiccatae see Gentry 1982; 586-590).The plants commonly occur in tropical savanna, thorn forest and drought-deciduous tropical forests.However, the species also survives in extreme habitats such as the arid Sonoran Desert with about 250 mm rain per annum and in montane pine-oak forests with a yearly precipitation of 1 680 mm.In these natural habitats, wild populations of A. vivipara exhibit a gradient in morphological variation, with characters such as plant size, length of leaves, dis tribution of marginal teeth and mass of leaf fibres show ing a high degree of plasticity.Also, improved growth conditions in gardens result in an increase in leaf length and fibre content and a decrease in thominess (Colunga-GarciaMarin & May-Pat 1997).
Since pre-Hispanic times, wild populations of A. vivipara have been prized by the inhabitants of central America not only for their fibres-which are used for hammocks, bags and fabrics-but also, the peduncles, leaves, stems and roots are used for building material, utensils, tools, food, fermented beverages and medicine (Cruz-Ramos et al. 1985;Colunga-GarcfaMarin & May-Pat 1993;Nobel 1994).With increasing attention being paid to the utilisation of invasive aliens (Zimmermann & Zimmermann 1987;Anon. 1988;Howell & Schnell 1991;Turksvykwekersvereniging 1997), southern Afri can environmentalists should take cognisance of the Mexican ethnobotanical uses of A. vivipara with a view to duplicating some of these practices locally.
The typical variety of A. vivipara is easy to distin guish from A. decipiens, the only species with which it can be confused in southern Africa.Important morpho logical distinctions between the two taxa are given below (Table 1).

AGAVE VIVIPARA A NATURALISED ALIEN IN SOUTHERN AFRICA '...invasive species are a kind o f habitat destruction. When invasive species take over a habitat, they erase the native richness and diversi ty o f species. What we really need is an everyday concern among ordi nary people about biodiversity and the issue o f invasiveness. ' -Dr Vandana Shiva in conversation with lU C N 's Ricardo Bayon (1997-1998)
The indigenous succulent flora of southern Africa rep resents 55 mostly unrelated plant families and includes all possible types of life forms.A small minority of exotic succulents (24 species according to Smith et al. 1997) can be regarded as naturalised in southern Africa.These species are mostly representative of the Cactaceae (19 species) and, to a much lesser degree, the Basellaceae (1 species), Agavaceae (2 species) and Portulacaceae (2 species)(Smith et al. 1997).Some of the species of Cactaceae, e.g.Opuntia ficus-indica (L.) Mill, (prickly pear) and O. aurantiaca Lindl.(jointed cactus) are aggressive noxious weeds that have invaded and trans formed certain parts of the southern African landscape.