Corresponding author: Annah Ntsamaeeng Moteetee (
Academic editor: James Cohen
The aim of the study is to provide a revision of the genus
Madika LK, Moteetee AN (2022) Taxonomic revision of the southern African species of the genus
The type genus
The genus is complex and has been noted by several botanists such as
An article by
In the southern African region, this genus has not yet been taxonomically revised since the last treatment by
A total of 316 specimens loaned from the following herbaria: PRE, GRA, NH, NU, NBG, and SAM (herbarium acronyms following
Data on vegetative morphology was obtained by analysing all the specimens provided per species. Inflorescence structures were studied from the freshly collected samples, herbarium samples, as well as from the original author’s descriptions (in a case where all the specimens did not contain any inflorescence to study). Hand drawings representing both the vegetative and reproductive characters were made for all the species (except for
Members of this genus are either perennial, biennial, or rarely annual herbs which are recognizable by their hairy stems and leaves. Roots are thickened cream white taproots with small lateral roots. The stems are erect, hollow, simple at the base, and usually branched above. The basal leaves are deciduous, long petiolate, lanceolate-obtuse shaped, cross-venulate, with smooth margins, and are clustered at the lower parts of the stem forming a rosette, covered with simple trichomes on both the adaxial and abaxial surface. The stem leaves are alternate, sessile, or petiolate, lanceolate-obtuse shaped, with smooth margins. Trichomes on the leaves sometimes have a pustulate base typical of
The inflorescence is a cyme which is often dichotomously branched with spreading panicles. Flowers are either pedicelled or subsessile, with five parted corollas; corolla white with a blue throat, blue, violet, or magenta (
Distinguishing characters between the southern African
Characters |
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Floral colour | Deep blue | Bluish purple | Pale blue | White with pale blue throat | Magenta | White with pale blue throat | Pale blue | White |
Nutlet shape and size | Convex, 6–9×5–6 mm | Ovoid to convex, 2–4×3–4 mm | Ovoid, 3.0–3.5×2.5–3.0 mm | Ovoid, 3–4×2.5–3.5 mm | Convex, 5–6×3–5 mm | Ovoid-convex, 3–4×2.5–3.5 mm | Ovoid-convex, 2–4×3–4 mm | Ovoid, ca. 4×5 mm |
Nutlet ornamentation | Glochidia densely packed on nutlet | Marginal glochidia are more distinct than the central glochidia | Glochidia more spread towards the margins | Glochidia more marginal and on the median line | Glochidia covering the whole nutlet | Glochidia sparsely arranged on nutlet | densely echinulate with glochidia | glochidia more marginal and acentric, marginal glochidia are longer compared to the acentric glochidia |
Perennial, biennial, or rarely annual herbs, often tall, up to 1,2 m in height, and slightly branched. Stems and leaves canescent. Indumentum white, simple or tubercled. Leaves alternate, lanceolate, obtuse or spathulate, entire; first year basal leaves form a rosette, lanceolate or obtuse, often long petiolate. Inflorescences usually elongate, rarely bracteate, sparingly branched or loosely paniculate. Flowers pedicelled or subsessile; blue or violet with distinct veins, rarely white. Calyx five-partite, scarcely enlarged in fruit, patent or reflexed. Corolla tube short, throat closed with obtuse or arched scales; five-lobed, imbricate, obtuse, patent. Stamens five, included in the corolla tube, included, with short filaments, anthers ovoid or shortly oblong, obtuse. Ovary with four distinct lobes from an almost flat receptacle; style short or rather long; stigma small, flat or sub capitate; ovules horizontal, fixed to the central angle of the cell. Nutlets four, depressed, scarcely produced at the apex, convex or flat on the dorsal side or surrounded by an elevated margin, glochidiate (hair-like spines or short prickles). Seeds straight or slightly curve
1 | Soft woolly hairs covering the entire plant; nutlets thickened; glochidia densely arranged on the nutlet |
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– | Stiff bristle hairs covering the entire plant; nutlets slightly swollen; glochidia sparsely spaced on the nutlet |
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2 | Nutlets 5 mm wide; glochidia thick at the base, fruit stalk up to 2 cm long |
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– | Nutlets less than 5 mm wide; glochidia uniformly shaped, fruit stalk up to 1 cm long |
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3 | Inflorescences clustered at the apex; corolla bluish purple; glochidia dense at the margins and centre of the nutlet |
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– | Inflorescences not clustered at the apex; corolla blue to white; glochidia dense at the margins and few at the centre of the nutlet |
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4 | Spreading long trichomes covering the whole plant; corolla longer than 7 mm long |
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– | Sparsely shorter trichomes covering the whole plant; corolla shorter than 4 mm long |
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5a | Corolla white with blue throat: | |
6 | Trichomes not thickened on both leaf surfaces; glochidia evenly distributed across the nutlet |
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– | Trichomes with pustulate base on the abaxial leaf surface; glochidia on the median line and centre of the nutlet |
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5b | Corolla uniformly coloured: | |
7 | Leaves brightly green coloured on both surfaces, lanceolate-obtuse shaped; corolla pale blue; length of glochidia uniform throughout the nutlet |
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– | Leaves grey green on the abaxial surface, dark green on the adaxial surface, spathulate-obtuse shaped; corolla white; marginal glochidia longer than acentric glochidia |
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South Africa ♀♂ Eastern Cape, Barkly East District (3027): Ben McDhui (-DB), 5 Feb 1983,
Perennial herbs, 0.2–0.6 m in height. Basal leaves 76–270×8–18 mm, lanceolate, densely pubescent, persistent; margins entire. Stem leaves 35–120×5–10 mm, lanceolate, apex acute, base cuneate, margins entire, soft woolly hairs. Trichomes spread equally on both the adaxial and abaxial leaf surfaces, unicellular hair base, not bulbous on both leaf surfaces. Inflorescence racemose, clustered at the apex; pedicel 4–10 mm long, lengthening considerably in fruit. Calyx ca. 4 mm long, lobes elliptic-oblong, densely hairy on inner surface, apices obtuse. Corolla deep blue; lobe 4×3 mm diameter, oblong, round apex. Nutlets convex, 6–9×5–6 mm; glochidia short and thick at the base, densely packed on nutlet, tips multi-angular (Figure
Vegetative and reproductive morphology of
February to May.
Least Concern (
The species is restricted to the Eastern Cape Province in South Africa and Lesotho (Figure
Distribution of
South Africa. Eastern Cape: 3028 (Matatiele): Drakensberg, near Barkly East (-CA), 19 Dec 1982,
Lesotho. 2929 (Underberg): Mokhotlong District (-AC), Jan 1953,
China ♀♂ Yunnan, Mengtsze, 1894,
Perennial herb, 0.6 m in height. Basal leaves 50–100×20–35 mm, lanceolate-elliptic shaped, softly hairy, deciduous, margins entire. Stem leaves 40–100×9–20 mm, lanceolate shaped, apex acute, base cuneate, entire margins, densely covered with white brittle hairs. Trichomes soft, upright, bulbous based. Inflorescence clustered at the apex, pedicels 5–8 mm long, lengthens considerably in fruit. Calyx ca. 3 mm long, lobes ovate, grey pubescent, apex subacute. Corolla bluish purple; lobe 7×9 mm diameter, segments round. Nutlets ovoid, 2–4×3–4 mm, convex shaped; glochidia short, thick, marginal glochidia are more distinct than the central glochidia (Figure
October to November.
Not evaluated (
Amongst the southern African species,
Recorded distribution of
South Africa. KwaZulu-Natal: 2930 (Pietermaritzburg): Richmond District, Byrne Village (-CD), 23 Nov 1977,
South Africa ♀♂, KwaZulu-Natal, Underberg (2929): Cobham Forest Reserve, Sipongweni, c.6500ft (-CB), 21 Feb 1981,
Perennial or biennial herbs, 0.3–0.5 m in height. Basal leaves 100–190×15–30 mm, lanceolate-obtuse, softly hairy, persistent margins entire. Stem leaves 45–100×10–21 mm, narrowly lanceolate to linear lanceolate shaped, acute apex, cuneate base, margins undulate, covered with stiff hairs. Trichomes unicellular, with thick round base on the adaxial surface, simple on the abaxial surface. Inflorescences dichotomously branched, loose cymes at the apex, pedicels 4–9 mm long, and lengthens considerably in fruit. Calyx ca. 2–3 mm long, lobes obtuse, pubescent on the outer surface, glabrous on the inner surface, apex acute. Corolla pale blue; lobes 2.75–4.25 mm in diameter, cruciform, apex obtuse. Nutlets ovoid, 3.0–3.5×2.5–3.0 mm; glochidia more spread towards the margins, thin, tip multi-angular (Figure
Vegetative and reproductive morphological features of
December to April.
Least Concern (
Amongst the southern African species,
The species is distributed in South Africa (North-West, Gauteng, Mpumalanga, Free-State, KwaZulu-Natal, and Eastern Cape Provinces), eSwatini and Lesotho (Figure
Known distribution of
South Africa. Limpopo: 2430 (Tzaneen): Lekgalameetse Nature Reserve (-AA), 7 Oct 1986,
eSwatini. 2631 (Mbabane): Forbes Reef (-AA), 14 Apr 1960,
Lesotho. 2828 (Bethlehem): Leribe District, LHDA Phase 1A (-AD), 11 Jan 1996,
No locality details: 27 Nov 1888,
According to
Cameroon ♀♂, Mount Cameroon, Dec 1862,
Perennial, biennial, or annual herbs, 1.2 m in height. Basal leaves 90–190×28–56 mm, lanceolate-obtuse, softly hairy, deciduous, margins entire. Stem leaves 35–90×7–25 mm, lanceolate, apex acute, base acute to obtuse, covered with moderately stiff hairs margins entire. Trichomes bulbous based on the upper surface of the leaf, sometimes simple on the lower surface. Inflorescences terminal axillary cymes, few branches spreading dichotomously; pedicel 4–8 mm long, lengthens considerably in fruit. Calyx ca. 21 mm long, lobes ovate-oblong, adpressed-hairy outside, smooth inside, apex acute. Corolla white with pale blue throat; lobes ca. 2.1 mm in diameter, campanulate. Nutlets ovoid, 3–4×2.5–3.5 mm; glochidia more marginal and on the median line (Figure
Vegetative and reproductive morphological features of
December to April.
Least Concern (
This variety can be easily confused with
This variety is endemic to South Africa where it is known only from KwaZulu-Natal and Eastern Cape Provinces (Figure
Known distribution of
South Africa. Kwazulu-Natal: 2731 (Louwsburg): Itala Nature Reserve (-AD), 10 Dec 1987,
(i)
South Africa ♀♂, Precise locality unknown, Lange Kloof,
Perennial or biennial herbs, 0.5–0.76 m in height. Basal leaves 80–250×15–25 mm, lanceolate-obtuse, densely pubescent, deciduous, margins entire. Stem leaves 60–80×5–12 mm, oblong-lanceolate, apex acute, base cuneate, covered with brittle hairs, margins entire. Trichomes bulbous based on the upper surface of the leaf, sometimes simple on the lower surface. Inflorescence terminal axillary cyme, branches spreading dichotomously; pedicel up to 20 mm long, lengthens considerably in fruit. Calyx ca. 5–10 mm long, lobes obtuse, outer surface packed with bulbous-based trichomes, apex acute. Corolla magenta; lobes ca. 5 mm in diameter, cruciform. Nutlets convex, 5–6×3–5 mm, highly pubescent; glochidia short and thick at the base, tips multiangular (Figure
Vegetative and reproductive morphological features of
October to March.
Least Concern (
The species can be confused with
This species is widely distributed across all provinces of South Africa. It can also be found in eSwatini and Lesotho (Figure
Known distribution of
South Africa. Limpopo: 2229 (Waterpoort): Evelyn valley (-BD), Feb 1944,
eSwatini. 2631 (Mbabane): Forbes reef (-AA), 29 Oct 1959,
Lesotho. 2928 (Marakabei): Ntiboho valley (-AC), 2 Jan 1947,
Unknown localities: Feb 1895,
Yemen, Al Hadiyah, Mar 1763,
Annual or biennial herbs, 0.5–0.9 m in height, covered with simple hairs. Basal leaves 85–180×15–23 mm, lanceolate-obtuse, blade elliptic, softly hairy, deciduous. Stem leaves 40–65×8–18 mm, lanceolate, apex acute, base cuneate, covered with moderately stiff hairs. Trichomes brittle, simple on both leaf surfaces. Inflorescence dichotomously branched axillary cyme, pedicel 1–1.5 mm long. Calyx ca. 1–1.5 mm long, lobe ovate-obtuse, pubescent on the outer surface, inner surface glabrous, apex acute. Corolla white with pale blue throat; lobes ca. 1×1 mm, campanulate. Nutlets ovoid-convex, 3–4×2.5–3.5 mm, fully pubescent; glochidia equally thick and long (Figure
Morphological characters of
August to May.
Least Concern (
Amongst the southern African species,
Known distribution of
South Africa. Limpopo: 2229 (Waterpoort): Wylies Poort (-DD), 17 Oct 1938,
eSwatini. 2631 (Hhoho): Hhoho District, Masilela area on Maphalaleni road along Mucucene Hills (-AB), 27 Jan 1994,
Lesotho. 2927 (Maseru): Monethi’s, Berea (-BB), 1 Jan 1957,
Unknown localities: No locality details, 30 Jan 1948,
The specimen in the National Herbarium Pretoria (PRE) collected in the Doornpoort area in Gauteng Province (Voucher number:
South Africa ♀♂, Western Cape, Worcester (3319): 20 km E. of Ceres (-AD), 21 Oct 1958,
Perennial or biennial herbs, ca. 0.45 m in height. Basal leaves 175–250×5–18 mm, obtuse, densely pubescent, persistent, margins entire. Stem leaves 50–65×5–10 mm, obtuse-lanceolate, apex acute, base cuneate, soft hairs.
Vegetative and reproductive morphological features of
The stems and leaves of
October to February.
Least Concern (
Known distribution map of
South Africa. Northern Cape: 3119 (Calvinia): Calvinia District (-BD), 22 Sep 1955,
South Africa ♀♂, KwaZulu-Natal, Underberg (2929): Underberg District, Cobham Forest Station, Polela valley (-CD), 20 Mar 1977,
Perennial herbs, ca. 0.4–0.5 m in height. Basal leaves 130–235×25–35 mm, spathulate-obtuse, soft hairs, deciduous, margins entire. Stem leaves 40–80×10–25 mm, obtuse shaped, dark green adaxial surface, grey green abaxial surface, smooth margins, soft hairs, sparsely packed. Trichomes unicellular, simple on both leaf surfaces, soft. Inflorescence corymbose panicle; threadlike pedicel 5 mm long. Calyx ca. 1.5–2.0 mm long, lobes lanceolate-oblong, softly hairy on the outer surface, inner surface smooth, apex acute. Corolla white; lobes ca. 3×3 mm diameter, obtuse. Nutlets ovoid, ca. 4×5 mm; glochidia more marginal and acentric, marginal glochidia are longer compared to the acentric glochidia (Figure
Morphological features of
Known distribution of
December to March.
Least Concern (
This species is characterised by leaves that are sparsely covered with hairs that have a softer feel, which distinguishes it sharply from all the other southern African species which have either brittle or woolly hairs. The abaxial leaf surface has a grey-greenish appearance which is also a unique character of this species.
The species is distributed in South Africa (Eastern Cape, Free-State, and KwaZulu-Natal Provinces) and Lesotho (Figure
South Africa. Kwazulu-Natal: 2729 (Utrecht): Ncandu State Forest (-DC), 8 May 1984,
Lesotho. 2927 (Maseru): Laikopile Mountain (-CD), Jan 1918,
We thank the curators of the following herbaria for the loans of material and provision of microfische images: PRE, GRA, NH, NU, and NBG including SAM. We thank Ezemvelo KwaZulu-Natal Wildlife for the plant collecting permit. We thank the University of Johannesburg for logistical and financial support. The first author is indebted to the National Research Foundation for financial support in the form of a bursary. The Central Analytical Facility of the Faculty of Science, University of Johannesburg (SPECTRUM) is acknowledged for assistance with scanning electron microscopy. We thank the three anonymous reviewers for their valuable input.