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Indigofera wenholdiae (Indigofereae, Fabaceae), a new
species from the Western Cape Province, South Africa
Brian du Preez1,2, Leanne L. Dreyer2, Charles H. Stirton1,
A. Muthama Muasya1, Brian D. Schrire3
1Bolus Herbarium, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch,
7701, South Africa 2Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland,
7602, South Africa 3 Comparative Plant and Fungal Biology Department, Royal Botanic Gardens, Kew,
Richmond, Surrey, TW9 3AE, UK
Corresponding author: Brian du Preez (brian.enviro@gmail.com)
Academic editor: Patrick Herendeen|Received 26 July 2021|Accepted 20 August 2021|Published 1 October 2021
Citation: du Preez B, Dreyer LL, Stirton CH, Muasya AM, Schrire BD (2021) Indigofera wenholdiae (Indigofereae,
Fabaceae), a new species from the Western Cape Province, South Africa. PhytoKeys 182: 107–112. https://doi.
org/10.3897/phytokeys.182.72170
Abstract
In this study, Indigofera wenholdiae, a new species of Fabaceae from the Agulhas Plain Region of the West-
ern Cape Province, South Africa, is described. A composite photographic plate is included along with a
distribution map, description of habitat and ecology and proposed IUCN conservation status. Indigofera
wenholdiae is unique in the I. brachystachya group by having digitately compound (vs. pinnately com-
pound) leaves, white and unscented owers (vs. pink and sweetly scented owers) and grows on sandstone
hillsides (vs. coastal limestone plains and outcrops).
Keywords
Indigofera, Leguminosae, Greater Cape Floristic Region, fynbos, taxonomy
Introduction
Fabaceae represents the second largest plant family in the Cape Floristic Core Cape
Region (CCR), approaching 800 species (Manning and Goldblatt 2012). e genus
Indigofera L. with about 90 species in the region, is second only to Aspalathus L.
Copyright Brian du Preez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC
BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PhytoKeys 182: 107–112 (2021)
doi: 10.3897/phytokeys.182.72170
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Brian du Preez et al. / PhytoKeys 182: 107–112 (2021)
108
(270+ species) in size (Dahlgren 1988; Schrire in Manning and Goldblatt 2012).
Indigofera species in the CCR are largely part of a monophyletic clade referred to as
the Cape Clade by Schrire et al. (2009). Unlike the three main tropical clades that
have members dispersed across multiple continents, the Cape Clade is endemic to
South Africa and especially within the winter-rainfall area (Schrire et al. 2009; Schrire
in Manning and Goldblatt 2012). A large group within the Cape Clade, Section
Brachypodae Schrire, is prolic in Fynbos vegetation and has many localised species,
often associated with preferences for specic microhabitats. Diverse geological forma-
tions, as seen in the Agulhas Plain region (waites and Cowling 1988), have resulted
in localised radiations in many plant groups (Cowling and Holmes 1992; Manning
and Goldblatt 2012). For example, over 20 new legume species have been recent-
ly described from various genera, including Aspalathus L., Otholobium C.H.Stirt.,
Polhillia C.H.Stirt., Psoralea L. and Rhynchosia Lour. (Curtis et al. 2013; Moteetee et
al. 2014; Stirton and Muasya 2016, 2017; Bello et al. 2017; Du Preez et al. 2021).
Members of Indigofera Section Brachypodae, particularly the I. brachystachya group
(I. brachystachya (DC.) E.Mey. and I. hamulosa Schltr.), are especially diverse in this
region, with several putative undescribed taxa related to I. brachystachya, noted from
recent eld studies (Schrire and du Preez, unpublished data). While further, more
detailed, analyses are required to resolve this species complex, we here describe a new,
distinctive species from the I. brachystachya group rst found in the Grootbos Nature
Reserve in 2020.
Material and methods
e description of morphological characters is based on freshly collected material and
herbarium voucher specimens. e conservation assessment was done using the Cat-
egories and Criteria of the IUCN (2012). e Extent of Occurrence (EOO) and Area
of Occurrence (AOO) were calculated using GeoCAT (www.geocat.kew.org). e dis-
tribution map was made using QGIS 3.18 software (www.qgis.org).
Species treatment
Indigofera wenholdiae du Preez & Schrire, sp. nov.
urn:lsid:ipni.org:names:77220006-1
Diagnosis. Similar to I. brachystachya, but diers in its digitately compound, 5–7 foliol-
ate leaves (versus pinnately compound, 7–9 foliolate leaves), leaets 4–6 mm long (ver-
sus leaets 9–15 mm long), racemes up to 7 mm long, owers ± 4–5 per raceme (versus
racemes > 10 mm long, owers > 8 per raceme), owers creamy white, unscented (versus
owers pale pink, scented), branching divaricate (versus branching random), popula-
tions restricted to sandstone fynbos (versus populations restricted to limestone fynbos).
Indigofera wenholdae (Indigofereae, Fabaceae) 109
Type. S A, Western Cape Province, track to Beacon Peak in Grootbos
Nature Reserve, Gansbaai District, elevation 257 m, 34°31'32.84"S, 19°30'19.08"E,
7 May 2020, owering, B. du Preez 836 (Holotype: BOL!; Isotypes: K!, NBG!, PRE!).
Description. Erect perennial shrub 0.4–0.8 m tall, robust, sparsely branching,
divaricate; obligate reseeder. Branches up to 10 mm thick, terete to ribbed on fresh
growth, densely strigose with sessile whitish biramous hairs, glabrescent later, reddish-
brown, woody. Stipules 0.8–1.2 mm long, ± 1 mm wide at base, broadly triangular,
asymmetric, navicular-cucullate, attenuate, apex aristate, adpressed to branch, adnate to
base of petiole, densely strigose, ± soft-textured and thickened, pale green, pearl bodies
present along margin. Leaves alternate, digitately 5–7 foliolate, petiole ± 1 mm long,
sub-terete, attened adaxially; rachis ± 0.5 mm long, terete, stipels absent; petiolules ±
0.5 mm long; terminal leaet 4–6 mm × 1.5–2.5 mm, narrowly oblanceolate, apex api-
culate, hooked, base cuneate, upper surface sparsely strigose, bright green, paler below;
lower surface densely strigose; mid-vein sunken adaxially, prominent abaxially; margins
not thickened, strongly revolute; lateral leaets similar, opposite. Racemes axillary, up
to 7mm long, erect, parallel with branch, roughly equalling the leaf length, including a
peduncle 2–3 mm long, ribbed, soft-textured; ± 4–5 owered; bracts± 1.5 mm long,
lanceolate, cucullate, apex apiculate, adpressed to petiole, persistent until after ower-
ing, pearl bodies present along margin. Bracteoles absent. Pedicels 1–1.5 mm long.
Figure 1. Indigofera wenholdiae du Preez & Schrire A single inorescence B ower lateral view
C leaf abaxial view D multiple inorescences on branches E whole plant. Photographs by Brian du Preez.
Voucher B. du Preez 836 (BOL).
Brian du Preez et al. / PhytoKeys 182: 107–112 (2021)
110
Flowers8–9 mm long, unscented. Corolla creamy-white, petals persistent after anthe-
sis. Calyx 3.5–4.2mm long, pale green, lobes lanceolate, distinctly navicular-cucullate,
2.5–3 mm long, ± three times tube length, moderately strigose, pearl bodies present
along margin. Standard petal 8.7–9.3 mm × 3.3–3.7 mm, broadly oblong, tapering
gradually to a short claw at the base; blade concave, nectar guide plain white; apex acute-
obtuse; back of standard strigose, no visible colouration patterns. Wing petals 7.5–8 ×
1.5–2 mm, shortly clawed at base, unguiculate portion ± half total petal length, blade
asymmetrically navicular, apex rounded; blade moderately strigose. Keel petals 7.5–8
× 1.8–2.3 mm, valvately connate distally, lateral spurs up to 1 mm long, blade asym-
metrically lanceolate, dorsal margin curving slightly downwards to an acute-obtuse apex,
densely strigose; claws 2.5–3 mm long. Stamens 5–5.5 mm long, exceeding calyx by 1.5–
2 mm, staminal tube pale creamy-green; hair clusters present below anthers. Gynoecium
4–4.5 mm long, strigillose on distal half; style ± 2 mm long, erect to±1mm high dis-
tally; stigma capitate. Fruit 13–16 × 2–2.2 mm, oblong, woody, reddish-brown, densely
strigillose, 4–5 seeded, dehiscent, ripe fruit not seen. Seeds not seen.
Distribution, habitat and ecology. Indigofera wenholdiae is restricted to a few sand-
stone hills from the Grootbos Nature Reserve to Pearly Beach on the Agulhas Plain of the
Western Cape Province (Figure 2). e species is occasional in Overberg Sandstone Fyn-
bos (FFs12, Mucina and Rutherford 2006), favouring south-facing slopes and hilltops.
Phenology. Flowering takes place from April to July.
Etymology. e specic epithet “wenholdiae” is assigned in honour of Mrs Han-
nerie Wenhold who has funded large-scale conservation eorts in this area, including
Figure 2. Distribution map of Indigofera wenholdiae.
Indigofera wenholdae (Indigofereae, Fabaceae) 111
the funding of the botanist post at Grootbos Nature Reserve of Miss Rebecca Dames
who brought this species to our attention in April 2020.
Conservation status. Indigofera wenholdiae is a range-restricted species, with an
EOO of 30 km2 and AOO of 24 km2. A total of six subpopulations across four locations
have been discovered, with the number of mature individuals estimated to be less than
10 000. Most subpopulations occur within protected areas or on farms earmarked for
conservation. Alien vegetation is prominent in the region, although only one location
is currently threatened by invasive species, while alien eradication projects at other loca-
tions have largely controlled or eradicated invasive species. e Red List category VU
D2 is thus recommended, based on the IUCN Categories and Criteria (IUCN 2012).
Related species. Indigofera wenholdiae is part of Section Brachypodae, a large group
(± 30 species) of Indigofera species almost exclusively found in Fynbos vegetation and
characterised by having ve or more foliolate leaves with short petioles. e I. brachys-
tachya group resolves within this section and includes I. brachystachya, I. hamulosa and
several putative undescribed taxa related to the former. All of these species are character-
ised by a corolla morphology unique in the genus, with elongate and concave standard
petals and, in general, robust rather than delicate petals. All species in this group are
coastally distributed and most often occur on limestone substrate. Apart from the distin-
guishing features noted above, I. wenholdiae is an erect to less than 1 m tall, divaricately
branching shrub with deep green leaves and white owers, in contrast with the bushier
growth of I. brachystachya, with its typically dull grey leaves and pale pink owers.
Additional specimens examined. Grootbos Nature Reserve, (3419DA), 12 Sep-
tember 2020, B. du Preez 879 (BOL, NBG).
Acknowledgements
e permit for the collection of herbarium specimens was obtained from the Western
Cape Nature Conservation Board (Permit: AAA 008-00222-0028). We wish to thank
Miss Rebecca Dames for bringing this species to our attention and who, along with
Mr Sean Privett, searched for and located further populations in the area. We wish to
also thank Mr Michael Lutzeyer for allowing us access to Grootbos Nature Reserve to
study this species. Running costs for research, including eldwork, were covered by an
NRF – FBIP grant awarded to Prof. A.M. Muasya (FBIP180529337017) and personal
bursaries awarded by the NRF – FBIP (FBIP 128327) and the Science Faculty PhD
Fellowship from the University of Cape Town.
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