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A new species of Polygala (Polygalaceae) from ultramafic soils in
Sekhukhuneland, South Africa, with notes on its ecology
S.J. Siebert
a,
⁎
, E. Retief
b
, A.E. Van Wyk
c
, M. Struwig
a
a
A.P. Goossens Herbarium, School of Environmental Sciences and Development, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa
b
National Herbarium, South African National Biodiversity Institute, Private Bag X101, Pretoria 0001, South Africa
c
H.G.W.J. Schweickerdt Herbarium, Department of Plant Science, University of Pretoria, Pretoria 0002, South Africa
Received 14 August 2009; received in revised form 7 January 2010; accepted 14 January 2010
Abstract
Polygala sekhukhuniensis Retief, Siebert & A.E.Van Wyk (Polygala; section Polygala; subsection Heterolophus), a new species with a
restricted range in Sekhukhuneland, South Africa, is described, illustrated and compared with other members of the genus. It is a dwarf shrub that
can be distinguished by its much-branched habit, sparsely flowered inflorescences, pink alae with darker pink veins, brown to black seed testa, and
oblate pollen grains with pronounced opercula. Geographically, P. sekhukhuniensis is confined to heavily eroded localized sites, a natural
geomorphological feature of some of the highly water-dispersible soils derived from ultramafic rocks in the valleys of the Steelpoort River and its
tributaries in the Sekhukhuneland Centre of Plant Endemism. P. sekhukhuniensis is a calciotrophic excluder of heavy metals that accumulates Ca
in its leaves. It is ecologically compared with co-occurring species of Polygala on ultramafic-derived soil.
© 2010 SAAB. Published by Elsevier B.V. All rights reserved.
Keywords: Bushveld Complex; Caruncle; Endemism; Heavy metals; Palynology; Sekhukhuneland Centre of Endemism; Taxonomy; Ultramafic rocks
1. Introduction
Since the pioneering work of Wild (1965) on plants
associated with soils rich in heavy metals and derived from
ultramafic rocks in southern Africa, and subsequent ground-
breaking research on plant-soil associations on southern African
serpentinites by Morrey et al. (1989), Williamson et al. (1997)
and Balkwill and Campbell-Young (2001), many plant species
new to science have been described from such substrates. In
recent years the Sekhukhune land Centre of Plant Endemism
(SCPE) in South Africa has been highlighted as an area
harbouring potential new plant species (Van Wyk and Smith,
2001). Siebert et al. (2001) showed that the high levels of plant
endemism of this region are significantly correlated with the
heavy metal soils derived from ultramafic rocks. In the last three
years, six new endemic plant species (including a new
monotypic genus, Prototulbaghia) were described from the
SCPE (Venter et al., 2007; Vosa, 2007; Burrows and Burrows,
2008; Hankey et al., 2008; Retief et al., 2008; Manning and
Goldblatt, 2009).
Massoura et al. (2004) have shown that plant species adapted
to heavy metal soils often accumulate or exclude metals that are
present in the soil at high concentrations. This physiological
adaptation is usually also expressed in the morphology through
ecological speciation (Balkwill and Campbell-Young, 2001;
Retief et al., 2008 ). Subsequent studies on heavy metal
accumulation by plants in the SCPE by Mandiwana et al.
(2007) have revealed several metal accumulators and excluders.
Such species are known to be genetically different from their
widespread congeners (Yang et al., 2005). This has warranted
taxonomic investigation into one such excluder that is tolerant of
soils rich in heavy metals, a member of Polygala that was initially
considered an ecotype of P. leptophylla Burch. var. leptophylla.
However, subsequent field work and comparative morphological
studies have shown the putative ecotype to be a distinct new
species related to members of section Polygala,subsection He-
terolophus (Paiva, 1998), specifically P. hottentotta Presl.,
P. leptophylla var. leptophylla and P. seminuda Harv. It is
confined to areas of highly water-dispersible soils derived from
A
vailable online at www.sciencedirect.com
South African Journal of Botany 76 (2010) 345 – 353
www.elsevier.com/locate/sajb
⁎
Corresponding author.
E-mail address: stefan.siebert@nwu.ac.za (S.J. Siebert).
0254-6299/$ - see front matter © 2010 SAAB. Published by Elsevier B.V. All rights reserved.
doi:10.1016/j.sajb.2010.01.003
ultramafic rocks. The new species is here described as Polygala
sekhukhuniensis Retief, Siebert & A.E.Van Wyk. This is the
second excluder of heavy metals, after Euclea sekhukhuniensis
(Retief et al., 2008), that is strictly confined to localized areas of
naturally eroded, ultramafic soils in Sekhukhuneland.
The aim of this paper is to describe and name the new taxon, and
highlight the morphological, palynological and ecological differ-
ences between the taxon and its most closely related congeners.
2. Materials and methods
2.1. Morphological assessment
Live material of the new species was extensively studied in the
field. Its morphology was compared to existing descriptions and
treatments of the genus (Exell, 1960; Paiva, 1998). Specimens of
Polygala housed in the National Herbarium (PRE), Pretoria and
H.G.W.J. Schweickerdt Herbarium (PRU), University of Pretoria,
were examined to gather quantitative and qualitative data on
morphology, phenology and distribution of the new species, as
well as related taxa. Micrographs of seed were taken with a Nikon
Digital Camera DXM 1200 F fitted on a Nikon SMZ 1500
stereomicroscope. Seed terminology follows Paiva (1998).
2.2. Palynological assessment
Mature, unopened flower buds from herbarium specimens
were dissected to obtain anthers with pollen. Unacetolyzed
pollen grains were mounted onto aluminium stubs, sputter-
coated with gold/palladium (Au/Pd) and examined with a FEI
Quanta 200 ESEM Scanning Electron Microscope (SEM). Ten
pollen grains per species were measured for polar length (P) and
equatorial width (E). Palynological terminology follows Punt et
al. (1994).
2.3. Plant-soil assessment
Plant material of the new species and P. hottentotta, as well
as soil samples were collected during early summer, environ-
mental factors were noted and associated plant communities
identified (Siebert et al., 2002). Samples were taken at ten sites,
five each dominated by either species. Soil analyses was done
with X-Ray Fluorescence (XRF) Spectrometry and plant
analyses with Atomic Absorption Spectrophotometry (AAS)
as well as Inductively Coupled Plasma-Mass Spectrometry
(ICP-MS). Terminology desc ribi ng exclus ion mechan isms
follows Massoura et al. (2004).
3. Taxonomy
The subcosmopolitan family, Polygalaceae, comprises a bout
19 genera and 925 species (Mabberley, 1997). The flowers are
superficially similar to those of members of the subfamily
Papilionoideae (Fabaceae). However, the wings (alae) of Po-
lygala flowers belong to the calyx and not to the corolla. The
standard is completely different and Polygala has a crest at the
tip of the keel. Currently various studies (Prenn er, 2004; Banks
et al., 2008) confirm the placin g of the erstw hile order
Polygalales in an expanded order Fabales (APG II, 2003). In
the Flora of southern Africa region, the genus Polygala is
represented by ± 88 species (Bredenkamp, 2000), of which ten
are currently known from the SCPE.
Polygala sekhukhuniensis Retief, Siebert & A.E.Van Wyk, sp.
nov.; fruticulus pumilus caulibus patentibus caudice lignoso;
caules foliaque sparse apprese hirsuti; folia spiraliter disposita,
lamine linearo-oblonge vel obovata, apice mucronata; calyx
sepalis duobus aliformibus, alis roseis; corolla carina cristata,
crista atrorosea vel purpurea.
Type. — 2430 (Pilgrim's Rest): Mpumalanga, Thornecliffe
Chrome Mine, turn off from Lydenburg-Sekhukhune road, [1
December 1997], Van Wyk 13031 (PRU, holo.; PRE, iso.).
Rigid perennial shrublet, 0.2–0.4 m high, with a woody
rootstock; stems and leaves sparsely adpressed-hairy; hairs
unbranched. Stems usually more than four from rootstock, erect
and spreading, branched, woody at base; young branches green,
herbaceous. Leaves spirally arranged, shortly petiolate; petiole
up to 0.75 mm long; blade linear-oblong or obovate, 7–15× 1.0–
2.5 mm, apex obtuse, occasionally acute, mucronate, margin
entire. Inflorescences comprising terminal racemes, peduncle up
to 80 mm long, pedicels 1.75 mm long. Flowers
irregular;
bi
sexual, drooping. Calyx pentamerous, with sepals unequal,
three outer ones sepaloid, two inner ones petaloid, larger wing-
like, 6–8 × 3.5–5.0 mm, all free; wings pink with darker pink
veins. Corolla of five petals, lowest one forming a carina, crested,
crest dark pink to purple, two lateral ones usually vestigial or
absent, two upper ones joined at base to carina and staminal tube.
Stamens eight, basally fused for ±two-thirds their length. Ovary
superior, two locular. Fruit a laterally compressed capsule, up to
6.5 mm long, membranous, edges wing-like, 0.25 mm wide,
deeply notched at apex, 2-seeded. Seed 4.5×1.5 mm, ellipsoid,
caruncle oblique, appendages poorly developed, single one
membranous, paired ones chitinous; indumentum silky white,
±1 mm longer than seed; testa dark-brown to black. Flowering
time: November to June. (Fig. 1).
3.1. Diagnostic characters and key to species
Polygala sekhukhuniensis and two related species, P.
hottentotta and P. leptophylla, are distinguished from P.
seminuda and the rest of the genus by their narrowly ovate
leaves, free anterior sepals, terminal racemes, wings not more than
6 mm broad, and the carina 6 mm long with crest 1–3mmlong.
P. sekhukhuniensis and P. leptophylla differ from P. hottentotta,
with the latter one having longer peduncles (124 mm versus 78–
90 mm), greater number of flowers per raceme (23 versus 7–12),
larger flowers (wing length 7.8 mm versus 6.8–7.0 mm), and
smaller seed (4.3×1.5 mm versus 5.6–5.9× 1.9 mm) (Table 1).
Morphologically P. sekhukhuniensis most closely resembles
P. leptophylla var. leptophylla , however, the leaf size of the
former is 7–15 × 1–2.5 mm, whereas the leaves of the latter one
are 14–22 × 1.5–3mm(Table 1). Flowers of P. sekhukhuniensis
differ from P. leptophylla var. leptophylla in the crest of the
former being purple and the alae pink with darker pink veins,
whereas the crest is white, pink or purple in the latter, with the
346 S.J. Siebert et al. / South African Journal of Botany 76 (2010) 345–353
alae whi tish to yellowish with green veins. Seeds of P.
sekhukhuniensis differ from P. leptophylla var. leptophylla in
the colour of the testa, dark brown-black versus reddish-brown,
the bare patch on the testa between the caruncle and the
indumentum (the size, 0.3 × 0.6 mm versus 1.2 × 1.5 mm), and
the caruncular appendages, poorly developed (0.2 versus
0.8 mm long) (Fig. 2 ; Table 1).
Key to the species of Polygala in Sekhukhuneland
1a. Plants procumbent, up to 50 mm high P. krumanina
1b. Plants erect, 50 mm to 1.5 m high 2
2a. Anterior sepals united for at least half their length P. uncinata
2b. Anterior sepals free or only slightly joined at the base 3
3a. Flowers solitary or in lateral racemes 4
3b. Flowers in terminal racemes, sometimes with additional
lateral racemes 5
4a. Flowers presented in a raceme, 30–140 mm long P. sphenoptera
4b. Flowers solitary, borne in leaf axils P. gerrardii
5a. Wings 7–15 mm broad; sturdy, erect shrublets up to 2 m tall P. virgata
5b. Wings less than 6 mm broad; slender, annual or perennial
herbs up to 0.5 m tall 6
(continued on next page)
Table 1
Mean measurements of selected morphological c haracters in Polygala
sekhukhuniensis and three closely related species (n =10/species).
Polygala
sekhukhuniensis
Polygala
leptophylla
Polygala
hottentotta
Polygala
seminuda
Number of flowers
per raceme
7±1.3 12 ±1.3 23 ±7.4 11 ±2.3
Inflorescence (mm)
Peduncle length 78 ±23 90 ±18 124±27 86 ±24
Flowers (mm)
Wing length 6.8±0.6 7.0±0.8 7.8±0.8 6.7±1.1
Wing breadth 4.1±0.7 3.5±0.5 4.0±0.7 3.7±0.9
Leaves (mm)
Length 11 ±2.2 19 ± 3.0 21 ± 5.9 20 ± 2.3
Breadth 1.4±0.5 2.1±0.5 1.4±0.8 1.4±0.5
Seed (mm)
Length 5.6±0.7 5.9±0.9 4.3±0.4 6.3±1.1
Breadth 1.9±0.5 1.9±0.4 1.5±0.7 1.7±0.5
Caruncle 3.1±0.8 3.0±0.7 2.2±0.5 3.5±0.7
Fig. 1. Polygala sekhukhuniensis. (A) Flowering plant, showing habit of above-ground parts; (B) Mature leaf; (C) Flower, lateral view; (D) Flower, lateral view with
wing-like sepal removed; (E) Old flower, lateral view with wing-like sepal removed to show capsule; (F) Ovary with style and stigma; (G) Androecium, showing
staminal tube joined at base to two upper petals; (H) Seed. Voucher: Van Wyk 13031. Scale bar 10 mm (A), 2 mm (B–E), or 1 mm (F–H). Artist: Daleen Roodt.
347S.J. Siebert et al. / South African Journal of Botany 76 (2010) 345–353
6a. Stems greyish; carina 3 mm long with crest 1 mm long P. seminuda
6b. Stems green; carina 6 mm long with crest up to 3 mm long 7
7a. Racemes longer than 100 mm; pedicels 2–3 mm long P. hottentotta
7b. Racemes shorter than 100 mm; pedicels 1–2 mm long 8
8a. Flowers crowded in terminal clusters on raceme P. gracilenta
8b. Flowers evenly spaced along entire raceme 9
9a. Leaves 16–22× 1.5–3.0 mm, apex acute; flowers with crest
white, pink or purple, alae whitish to yellowish with dark
green veins
P. leptophylla
9b. Leaves 9–15 × 1.0–2.5 mm, apex obtuse or retuse; flowers
with crest purple, alae pale pink with dark pink veins
P.
sekhukhuniensis
3.2. Palynology
In a review of Polygala palynological literature (Banks et al.,
2008), no mention is made of descriptions, drawings, or
micrographs of pollen belonging to the species compared in this
paper. Hence, the SEM observations on pollen grains presented
here are the first for the four taxa concerned (Fig. 3).
Pollen of P. sekhukhuniensis is isopolar and spheroidal in
equatorial view; P×E=(23)–25.64–(27)× (24)–25.06–(26)
μm; P/E =1.02 (Table 2). Apertures 22, zonocolpor ate.
Fig. 2. Stereomicroscope micrographs of seed and caruncle. (A) Polygala sekhukhuniensis, membranous appendage (me) 2.9 mm and chitinous appendage (ch) 0.8 mm,
hairs cover seed surface completely; (B) P. leptophylla var. leptophylla, me 2.7 mm and ch 1.6 mm, hairs cover two-thirds of the seed surface; (C) P. hottentotta, me 2.1 mm
and ch 1.0 mm, hairs cover seed surface completely; (D) P. seminuda, me 3.8 mm and ch 2.5 mm, hairs cover half of the seed surface. Scale bars 1 mm.
348 S.J. Siebert et al. / South African Journal of Botany 76 (2010) 345–353
Ectoapertures (17)–18.6–(21) × (1)–1.2–(3) μm; endoapertures
(1)–4.8–(6) μm × endocingulate. Surface ornam entation psilate
to finely granular, with scattered lumina in apocolpial areas that
are small (less than 1 μm). Opercula present.
Pollen grains of P. sekhukhuniensis,andP. hottentotta differ
from P. leptophylla var. leptophylla and P. seminuda in shape,
namely oblate versus prolate and prolate-spheroidal respective-
ly (Fig. 3). Opercula over the endoapertures of P. sekhukhu-
niensis, P. hottentotta and P. seminuda are pronounced, mostly
so in the new species (Fig. 4). Although the shape of pollen
grains of P. sekhukhuniensis and P. hottentotta are very similar,
the former has smaller grains (Table 2).
Fig. 3. SEM micrographs of pollen. Polar view to the left. (A) Polygala sekhukhuniensis; (B) P. leptophylla var. leptophylla; (C) P. hottentotta; (D) P. seminuda.
Scale bars 10 μm.
349S.J. Siebert et al. / South African Journal of Botany 76 (2010) 345–353
3.3. Distribution and ecology
Polygala sekhukhuniensis is only known from Sekhukhune-
land (Fig. 4). P. sekhukhuniensis and P. hottentotta occur on
patches of anomalous soils in this region — sparsely vegetated
soils that are mineralized and rich in heavy metals (Table 3).
These soils are clayey and highly erodible, in contrast to the
rocky, sandy soil on mountain slopes that is preferred by P.
leptophylla var. leptophylla. These anomalies are akin to erosion
gulleys, but in this case not due to human disturbance, but caused
by natural erosion processes due to a weak soil structure and
associated high water dispersability (Mason, 1959). According to
Siebert et al. (2002) and Mandiwana et al. (2007), plant
communities typical of these eroded sites in Sekhukhuneland
include heavy metal accumulating or excluding species (Table 4).
Polygala sekhukhuniensis is such a species, specifically
adapted to grow in erosion gulleys of exposed heavy metal
contaminated (ultramafic) soil. Hence, the opinion that the
ecological species concept is an essential part of the biological
species concept (Grant, 1992) is supported here. Asymmetry and
within-plant variance are higher between specimens of the same
species in the contact zone between ultramafic and normal soils
(Alados et al., 1999). This variance provides genetic material for
natural selection and subsequent reproducti ve isolation.
In the case of P. sekhukhuniensis, an open niche with an
anomalous Ca-rich substrate (14.68% =146 800 ppm) in an
otherwise typical environment of soils rich in Mg (8.48% =
Table 2
Mean measurements (μm)/counts of selected pollen characters of Polygala sekhukhuniensis and three closely related species (n=10/species).
Polygala sekhukhuniensis Polygala leptophylla Polygala hottentotta Polygala seminuda
Nr. of apertures 22 20 21 21
Polar length 25.64 ±1.3 40.54±2.9 30.29±1.2 33.34±3.9
Equatorial breadth 25.06±0.9 25.98±1.8 33.27±1.4 29.66±1.5
P/E 1.02 1.56 0.91 1.12
Polar diameter 14.79 ±1.3 18.25±3.7 16.84±1.3 17.93±1.5
Ectoapertures lxw 18.6 × 1.2 30.6×0.8 22.9×1.1 26.4 ×1.3
Endoapertures lxw 4.8 ×endocingulate 2.1×endocingulate 6.9×endocingulate 5.3×endocingulate
Fig. 4. Known distribution of Polygala sekhukhuniensis.
Table 3
Environmental variables unique to plant communities containing either
Polygala sekhukhuniensis or P. hottentotta in the Sekhukhuneland Centre of
Plant Endemism.
Characteristics P. sekhukhuniensis P. hottentotta
Slope (°) 4 (0–7) 8 (0–15)
Aspect N, S, E, W S, W
Rock cover (%) 30 (5–55) 45 (20–70)
Rock size (mm) 150 (100–500) 450 (300–1500)
Soil type Valsrivier, Prieska,
Mayo, Bonheim
Glenrosa, Mispah,
Valsrivier
Geology Norite, pyroxenite,
gabbro, alluvium
Pyroxenite, magnetite
Topographical position Footslope, valley Footslope, crest
Vegetation type Tall, sparse shrubland Short, open shrubland
350 S.J. Siebert et al. / South African Journal of Botany 76 (2010) 345–353
84 800 ppm) and poor in Ca (2.13% = 21 300 ppm) (Fig. 5A),
probably favoured speciation. Similar to limestone, the soils
inhabited by P. sekhukhuniensis have a high Ca:Mg ratio (2:1),
which d iffer significantly from the soil substrate of P.
hottentotta (1Ca:4 Mg) in the study area (Fig. 5A). As a
consequence P. sekhukh uniensis has a leaf Ca:Mg ratio of 16:1,
and P. hottentotta a ratio of 4:1 (Fig. 6A). O'Dell et al. (2006)
have shown that the ability to maintain high leaf Ca:Mg is a key
evolutionary change needed for survival on heavy metal soil
and represents the physiological feature distinguishing the plant
species adapted to heavy metal soils from their non-adapted
congeners.
Furthermore, soils in which the two Polygala taxa grow have
high concentrations of total Cr, Al and Fe (Fig. 5A,B), with
Polygala hottentotta holding higher concentrations of Al and Fe
in its roots, stem s and leaves , but not at levels that could be
considered as accumulating (Fig. 6B). P. sekhukhuniensis
excludes these metals more effectively, despite the associated
soil concentrations being higher (Fig. 5B). Overall it seem s that
P. sekhukhuniensis is the better excluder of heavy metals due to
higher leaf Ca concentrations as a previously confirmed pro-
tection and survival mechanism (Konstantinou and Babalonas,
1996).
It is suggested that P. sekhukhuniensis originated as an
ecotype of and has developed from its suggested closest
relative, P. leptophylla, which occurs on nearby mountain
slopes. This theory was already proposed for Sekhukhuneland
endemics by Knowles and Witkowski (2000), suggesting that
the genetic properties of indi viduals occurring on iron-rich
mountain slopes have the potential to immigrate to, adapt to and
colonize ultramafic soils rich in heavy metals. It is hypothesized
that P. sekhukhuniensis is a typical edaphic specialist which
may well have speciated recently, after the Pleistocene (Reeves
et al., 1983). It probably prefers the competition-free, open
Table 4
Prominent associated taxa recorded for plant communities containing either
Polygala sekhukhuniensis or P. hottentotta in the Sekhukhuneland Centre of
Plant Endemism (Siebert et al., 2002).
Life forms Species dominant in:
P. sekhukhuniensis community P. hottentotta community
Grass layer Aristida congesta Diheteropogon amplectens
Fingerhuthia africana Loudetia simplex
Stipagrostis hirtugluma Themeda triandra
Forb layer Aloe cryptopoda Berkheya insignis
Dicoma gerrardii Jamesbrittenia macrantha
Gnidia polycephala Petalidium oblongifolium
Shrub layer Euclea sekhukhuniensis Searsia sekhukhuniensis
Grewia vernicosa Tinnea rhodesiana
Searsia keetii Vitex obovata
Tree layer Acacia sp. nov. Bolusanthus speciosus
Euphorbia tirucalli Combretum hereroense
Fig. 5. Chemical analyses of five soil samples collected from the root zone (300 mm deep) for each of Polygala sekhukhuniensis and P. hottentotta. Bulked sample per
species.
351S.J. Siebert et al. / South African Journal of Botany 76 (2010) 345–353
niches of eroded, toxic ultramafic soils where it has a
physiological advantage requiring high levels of Ca to tolerate
heavy metals (Fig. 6A). P. sekhukhuniensis,likeEuclea
sekhukhuniensis, can therefore be considered a heavy metal
excluding, calciotrophic species.
3.4. Conservation status
Polygala sekhukhuniensis has a small geographical range in
Sekhukhune Plains Bushveld (Siebert et al., 2002), and limited
area of occupancy within natural erosion gulleys (dongas). Most
of its habitat is under threat from slimes dams and rock dumps
associated with the min ing industry, as these eroded areas are
considered to be of low conservation status. P. sekhukh uniensis
is not formally protected in any conservation area. Populations
of the species should therefore be closely monitored and its Red
Data List assessment assessed. The conservation value of P.
sekhukhuniensis is considered relatively high, as it could
possibly be used as a keystone species in the ecology of mine
dumps due to its internal mechanism of excluding heavy metals.
3.5. Etymology, vernacular names and uses
The specific epithet refers to the geographical area the
species occurs in, namely Sekhukhuneland, a region named for
King Sekhukhune(-i) I (1814–1882) of the Bapedi tribe. For
consistency, and in line with existing Latin epithets of plants
named after the region, it is based on the alternative spelling,
“Sekhukhunila nd”. We would like to propose the names
“sekhukhune milkwort” and “sekhukhunebloukappie” as Eng-
lish and Afrikaans vernacular names, respectively. The
recorded Northern-Sotho names for the plant are mabošêkgo
and mogaletsaoi, which differs from the vernacular name, pe-
loterri, given to the closely related P. leptophylla var.
leptophylla.
Burnt ashes are mixed with snuff for flavouring (Barnard
209) and the roots are cooked and given to forgetful people to
make the mind sensible (Barnard 135).
3.6. Additional specimens examined
LIMPOPO. — 2429 (Zebediela): Mankopanie, Farm Hoera-
roep (–BD), Barnard 209 (PRE); Bewaarkloof, Potlake Nature
Reserve (–BD), Van Rooyen 2339 (PRE); Potlake Nature Reserve
(–BD), Matthée 1044 (PRU); Farm Geeneinde, Sekukuniland (–
DB), Barnard & Mogg 737 (PRE); Sekhukhuniland, Farm Parys
(–DB), Barnard & Mogg 738 (PRE).
MPUMALANGA. — 2430 (Pilgrim's Rest): Maandagshoek
(–CA), Kritzinger 118 (PRE, PRU); Steelpoort, Eastern Chrome
Mines, valley beneath mountain in the Winterveld mine area
Fig. 6. Chemical analyses of plant material from five individuals each of Polygala sekhukhuniensis and P. hottentotta (young and old growth). Bulked sample per
species.
352 S.J. Siebert et al. / South African Journal of Botany 76 (2010) 345–353
(–CA), Siebert 44 9 (PRU); Sekukuni (–CC), Barnard 135
(PRE); Dwarsrivier, 5 km on turn-off to Lydenbu rg from
Stofberg-Steelpoort road (–CC), Jordaan 782 (PRE); 2 km
from Spitskop turn-off south on Steelpoort-Lydenburg road (–
CC), Burgoyne 6015 (PRE); Thornecliffe Chrome Mine, hill
west of office ( – CC), Van Wyk & Siebert 12982 (PRU);
Steelpoort, Ferrochrome Holdings, 4 km to east of Spitskop on
waytoRoossenekal(–CC), Siebert 337 (PRU); Turnoff to
Thornecliff e Mine from Lydenbur g, Steelp oort road ( –CC),
Van Wyk & Siebert 13311 (PRU); Road between Steelpoort
and Kennedy's Vale (–CC), Siebert & Van Wyk 1379 (PRU).
Acknowledgements
The autho rs are indebted to Ma ggi Loubser, Geology
Department, University of Pretoria, for assistance with XRF
analyses and to Nina van Vliet, Department of Soil, Climate and
Water, Pretoria, for assistance with AAS and ICP-MS analyses.
We would like to thank Hugh Glen, for translating the
diagnoses into Latin, Kevin Balkwill for constructive comments
on a draft of the manuscript, Hester Steyn, for preparing the
distribution map and Daleen Roodt for the line drawings. The
National Research Foundation, University of Pretoria and South
African National Biodiversity Institute provided financial
support.
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Edited by B-E Van Wyk
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