Corresponding author: Harold Robinson (
Academic editor: A. Sennikov
Deceased 2 March 2014
Current and previously included members of the Tribe
Pollen types are illustrated including previously recognized types: non-lophate, sublophate, tricolporate lophate, and non-colpate triporate lophate. A type previously unknown in the
Robinson H, Skvarla JJ, Funk VA (2016) Vernonieae (Asteraceae) of southern Africa: A generic disposition of the species and a study of their pollen. PhytoKeys 60: 49–126. doi:
Attempts to revise the generic concepts of the tribe
The initial reference used for members of the
Some of the proper generic dispositions were established in various papers such as
In the following treatment, each genus is described or redescribed with general habit, types of vegetative trichomes, head structure, achene setulae and other trichomes, idioblasts and raphids, pappus form, and pollen form. Secondary metabolite chemistry is indicated based on data from two rather extensive summaries of constituents in the tribe by
Figures are numbered in the order of the taxonomic treatment. Among the characteristics used in the classification, some special comments are in order.
The trichomes of the African
The pollen is complicated, showing variation from nearly non-lophate to sublophate or lophate with or without colpi (Figs
Regarding the lophate condition, in reality, none of the grains in the
In addition to the sublophate pollen types described above, there are many variations of lophate grains, grains with ‘perforated tectum lacking’ to various degrees in the lacunae or even on the muri. Of these lophate types, one variant, represented by
The most systematically important subdivision among the lophate types of pollen are the strongly colporate types as seen in
A different pattern is seen in the many members of the subtribes
The triporate grains in the
The genera
The genera discussed in the section below fall into a number of subtribes. Some genera, from the more basal subtribes (based on DNA studies by
The
Most of the remaining genera in the study, on the basis of DNA, structural or other evidence are presently placed in the subtribe
The genus
Subtribe
Subtribe
Subtribe
Subtribe
Subtribe
Subtribe Unknown:
The presently recognized genera of the
1 | Leaf venation triplinervate; flowers usually yellow or orange, sometimes purple or white (Subtribe |
|
– | Leaf venation pinnate or without evident secondary veins; flowers usually purple or blue, sometimes white, never yellow or orange |
|
2 | Plants woody, shrubs or small trees; outer surfaces of involucral bracts with broad smooth shields, without evident strong midveins or keels (Subtribe |
|
– | Plants herbaceous or small shrublets; outer surfaces of involucral bracts narrow or with midveins or keels |
|
3 | Involucral bracts usually with rounded tips and with the scarious margin continuous across tip |
|
– | Involucral bracts with acute or awned tips; without continuous scarious margins across tips |
|
4 | Plants with either involucral bracts with spicules on margins or with broad flattened pappus bristles; pollen lophate and tricolporate, sometimes not echinate (subtribe |
|
– | Plants with neither involucral bracts with spicules on margins nor with broad flattened pappus bristles; pollen nearly nonlophate or sublophate and echinate or triporate, not lophate combined with tricolporate |
|
5 | Involucral bracts without spicules along margins; basal tubes of corollas slender with expanded throat longer than the lobes; pappus bristles broad and flattened outside; pollen with polar lacunae, without spurs projecting into colpi |
|
– | Involucral bracts with spicules along lateral margins; corollas funnel-form with lobes longer than throat; pappus bristles capillary, not flattened outside; pollen without polar lacunae, with spurs projecting into colpi above and below pores |
|
6 | Setulae of achenes deeply divided, sometimes with single cell from near base; hairs of stems simple; pollen tricolporate, non-lophate (typical element of subtribe |
|
– | Setulae of achenes, when present, with pairs of cells not or scarcely divided at tips; hairs of stems simple, T-shaped or L-shaped; pollen triporate or polyporate without colpi or non-lophate and tricolporate (some |
|
7 | Pappus bristles elongate and subplumose |
|
– | Pappus bristles absent, short, scabrid or barbellate |
|
8 | Involucral bracts ca. 80 in ca. 6 series; stems with asymmetrical L-shaped hairs, with cap-cell mounted near one end; pollen pantoporate |
|
– | Involucral bracts less than 50 in less than 5 series; stems with variously shaped hairs; pollen triporate |
|
9 | Pollen sublophate, without distinct polar lacunae |
|
– | Pollen lophate and triporate, with irregular cluster of polar lacunae |
|
10 | Pappus totally lacking or present as cylindrical collar |
|
– | Pappus with capillary bristles |
|
11 | Heads few or solitary at tips of long branches or peduncles; stems with short often asymmetrically capped hairs |
|
– | Heads clustered at tips of branches; stems usually with T-shaped hairs |
|
12 | Stems with yellowish-brown-velutinous pubescence (unplaced) |
|
– | Stems with sericeous to hirsute pale pubescence |
|
13 | Inflorescences with heads in corymbiform cymes; stems, involucres and corollas with symmetrically T-shaped hairs |
|
– | Inflorescence with heads in seriate cymes; corollas without T-shaped hairs |
|
14 | Pappus bristles much shorter than corollas or lacking, easily deciduous; achenes short and broad, narrowed greatly apically to the narrow insertion of the corolla |
|
– | Pappus bristles about as long as corolla, rather persistent; achenes not greatly narrowed distally to insertion of corolla |
|
15 | Hairs of stems often T-shaped with long arms; leaves alternate, opposite or whorled; corolla lobes without long hairs at apex; achenes with few raphids or thick sclerified layer inside of wall; pollen with 2 or 3 lacunae with incomplete muri adjacent to pores |
|
– | Hairs of stems and branches simple with short basal cells and long flexuous terminal cell; leaves alternate; corolla lobes with long hairs at apex; achenes without thick sclerified layer inside, with well-developed layer of dense subquadrate cells containing subquadrate or short-oblong raphids; pollen strictly triporate |
|
16 | Hairs of stems simple or asymmetrical; achenes with numerous idioblasts densely clustered in transverse bands |
|
– | Hairs of stems symmetrically T-shaped; achenes with idioblasts not in distinct transverse bands |
|
17 | Short-lived herbs; hairs with long armed cap cells, forming hirsute or pilose indument |
|
– | Small subshrubs; hairs of stems and bracts with small or elongate cap-cells, forming dense tomentellous or sericeous cover |
|
Treatment by
Annual or perennial herbs, suffruticose; stems erect or reclining; hairs short-stalked with an erect, elongate apical cell. Leaves alternate, narrowly petiolate; blades chartaceous, ovate to elliptic, serrate, secondary veins pinnate, ascending at 45° angles or more. Inflorescence with single lateral or terminal head or heads in corymbiform groups; peduncles usually solid, sometimes fistulose. Heads with involucres broadly campanulate or hemispherical; bracts 25–100 in 4–8 series, mostly gradate but with outer bracts sometimes elongate and foliiform, tips of bracts appendaged, white or colored; receptacles epaleate. Florets 25–100 in a head; corollas reddish or lavender to white, with long slender basal tube, limb abruptly expanded at base, cylindrical, with lobes about as long as throat, erect, with various hairs and glands outside, inside with cells elongate, transversely striate; anther thecae spurred with small tails; endothecial cells with nodular thickenings on tranverse walls; apical appendages oblong-ovate, rounded or acute at tips, glabrous; nectary elongate, cylindrical; style base without node; sweeping hairs acicular. Achenes cylindrical or turbinate, 8–20-costate, glabrous or with setulae distinctly cleft or with glands or idioblasts, carpopodium annuliform, large to obsolete, with thickened porose walls, raphids in ovules elongate, with rhomboid tips; pappus pluriseriate, persistent or caducous, inner capillary, flattened, barbellate on margins, sometimes shortly connate at base, sometimes with outer row of small scales. Chromosome number x = 10 (
Pollen. 43.5–72.0 μm diam. (
Photographs of
Illustrations:
Scanning electron electron micrographs from three collections of acetolyzed echinolophate
Most notable secondary metabolites, sesquiterpene elemanolides (
1 | Leaf blades sessile or subsessile |
|
– | Leaves distinctly petiolate |
|
2 | Branching perennial herbs from large root crown; fusiform tubers often present; peduncule not enlarged or fistulose distally |
|
– | Annual herbs; without tubers; peduncles often somewhat enlarged and fistulose distally |
|
Ivory Coast, Ethiopia, Malawi, Mozambique, Zimbabwe, South Africa.
Congo, Kenya, Tanzania, Uganda, Malawi, Zambia, Zimbabwe, Botswana, Namibia, Sri Lanka, Nepal, Pakistan, India, China.
Angola, also cited from SW Africa, but that locality probably not intended in the restricted sense.
The species is known from photographs of types and from descriptions deposited at
Many species are keyed in
Perennial herbs (up to 1 m) to subshrubs, branching sparse, stems erect with a solid pith and long-armed T-shaped hairs with short 2-celled stalks. Leaves alternate, opposite or whorled, sessile to short petiolate, blade narrow to ovate or elliptical, pinnately veined, often paler or tomentose to sericeous below. Inflorescence laxly to densely corymbiform or thyrsiform cymes; heads pedunculate. Involucres campanulate, bracts ca. 50–60, gradate in 3–4 series, cuspidate at apex, with distinct pale or reddish lateral margins, nearly glabrous to pilosulous outside; receptacle convex, epaleaceous, with glabrous reticulum. Florets 3–100 or more in a head; corollas purplish, funnelform, basal tube slender with small stipitate glands, throat shorter than 1 mm, lobes, linear-lanceolate, with glandular dots and often with stiff subapical hairs; anther thecae blunt at base with few sterile cells; apical appendages ovate-oblong, with thin cell walls; style base with minimal annuliform node; sweeping hairs acicular, mostly restricted to branches. Achenes prismatic, short and broad with 3–6(–9) ribs, setuliferous with sparse short setulae scarcely split at tips, often densely covered with idioblasts and with scattered subquadrate raphids. Pappus of few or no short easily deciduous bristles narrowed at base, without obvious shorter ourter series or outer pappus a rim or collar. Chromosome number n = 9, 10, 18–20 (
Scanning electron micrographs of acetolyzed pollen of echinolophate
Notable secondary metabolites include 5-alkylcoumarins and sesquiterpene glaucolides/hirsutanolides [
Tanzania, Zambia, Malawi, Zimbabwe, Congo, Angola, South Africa (Transvaal).
Traditionally treated as part of
Annual or short-lived perennial herbs to 1 m tall; stems erect or spreading; hairs symetrically or asymetrically T-shaped with short stalk. Leaves alternate; petioles narrow; blades membranaceous, ovate to narrowly lanceolate. Inflorescences terminal, moderately densely to laxly branching, distinctly cymiform or with rather corymbiform branches, with minute bracteoles; peduncles rather short to elongate. Heads narrowly campanulate, involucral bracts ca. 30 in 3(–5) series, gradate, thinly chartaceous, green with pale or purplish margins, persistent, often with pilose to sericeous pubescence; receptacles epaleaceous. Florets 15–94 in a head; corollas bluish to lavender, funnelform with slender lower tubes, throat a third as long to nearly as long as lobes, lobes with simple hairs especially near tips; anthers without tails; apical appendages oblong-ovate, glabrous, with thin cell walls; style base with broad node; style branches with acicular sweeping hairs. Achenes 5-ribbed, or terete, setulae shortly cleft at tips, with idioblasts, sometimes with glands, raphids elongate; inner pappus of many long, sometimes rather fragile, slender-tipped capillary bristles, outer series of persistent squamellae, one species with callose ring. Chromosome number n = 9, 18, 20 (
Pollen ca. 30 μm in diameter (dry); triporate, echinolophate, ca. 21 lacunae rather irregularly disposed at poles and in intercolpi; perforated tectum restricted to ridges of muri, with distinct microperforations; spinules of muri short, shorter than width of mural ridge, pointed, without columellae under each murus; baculae single at junctures of muri and no baculae between junctures, each intersection of muri with stout columella that is firmly attached to footlayer (Fig.
Photographs of
Notable secondary metabolites, 5-alkylcoumarins, sesquiterpene glaucolides, guanolides (
1 | Plants perennial, weakly frutescent, often scrambling |
|
– | Plants annual |
|
2 | Inner pappus absent or of few dissected scales; outer pappus forming a collar |
|
– | Inner pappus of many bristles; outer pappus not forming a collar |
|
3 | Outer pappus of short oblong often rounded scales less than 0.2 mm long |
|
– | Outer pappus of narrow lanceolate scales 0.2 or more long |
|
Widely introduced weed, pantropical.
Tropical Africa south to Angola.
Tropical Africa from Congo, Uganda and Kenya south to Zambia, Zimbabwe and South Africa (Transvaal), Madagascar.
Abyssinia, Malawi, Sudan, Swaziland, Tanzania, South Africa (Transvaal), Uganda, Zimbabwe.
For discussion and numerous transfers of species see treatment by
Shrubs or vines; hairs arachnoid, contorted or asymmetrically T-shaped. Leaves alternate; petioles short; blades ovate to rounded, often with truncate to subcordate bases, less often narrow with cuneate bases, margins usually entire or subentire, venation usually with stronger more ascending basal pair or strongly triplinervate, less often irregularly pinnate. Inflorescences terminal on stems or branches, with single heads or usually branching, corymbiform with minute bracts or thyrsoid with foliose bracts; peduncles usually short. Heads with campanulate involucres; bracts 21–24(–75) in 4–6(–7) gradate series, without appendaged tips; receptacles epaleaceous. Florets 10–16(–75) in a head; corollas usually yellow, purplish in a few continental African species; anther thecae with distinct broad often sclerified basal appendages; endothecial cells with simple, broad, non-contiguous, sclerified shields; apical appendages without glands; style base with large abruptly distinct node; style branches with obtuse sweeping hairs. Achenes cylindrical to prismatic, sometimes subtriquetrous or quadrangular, with 5–12 ribs, usually 10, setulae or glands present or absent, raphids elongate; carpopodium turbinate; pappus of many capillary bristles, outer series of squamellae. Chromosome numbers n = 9, 10, 15 (
Pollen: 30–36 μm in diameter (dry); tricolporate, sublophate to lophate; lophate forms with muri projecting as spurs into colpus, with echinate or with nearly psilate ridges; tectum continuous in intercolpi and at poles, or in pockets surrounded by ridges, with distinct perforations; with columellae under spines or with muri granular inside, without distinct baculae (Figs
Photographs of
Notable secondary metabolites: sesquiterenes, elemanolides (Bohlmann and Jakupovic, as
1 | Involucral bracts oblong with obtuse or shortly acute tips |
|
– | Involucral bracts lanceolate, narrowly acute |
|
2 | Leaf blades ovate, with marginal lobes; branches of inflorescence essentially straight; corollas purple or yellow |
|
– | Leaf blades rhomdoidal, cuneate proximally; inflorescence branches with strong zigzag pattern; corollas white |
|
3 | Corollas purple or white |
|
– | Corollas yellow or orange |
|
4 | Stems and abaxial surfaces of leaves not tomentellous; leaf blades oblong or ovate-elliptical, often blunt at tip |
|
– | Stems and abaxial surfaces of leaves with fine tomentellum; leaf blades ovate, broadest at or below proximal third |
|
Angola, Namibia.
Mozambique, South Africa (Natal, Transkei).
South Africa (Cape colony, Natal).
Angola, Botswana, Congo, Ethiopia, Kenya, Malawi, Mozambique, Namibia, Tanzania, South Africa (Transvaal), Zambia, and Zimbabwe.
Mozambique and South Africa (Natal).
Species treatment based on
Annual or short-lived perennial herbs; stems erect, branching near base; hairs on vegetative parts simple, uniseriate, multicellular, with a straight elongate apical cell. Leaves alternate, sessile or subsessile, pinnately veined with weak secondary veins, margins serrulate, apices obtuse. Inflorescence with single terminal head or laxly cymiform with narrowly pedunculate heads. Heads campanulate; involucral bracts 45–60 in 3–4 series, gradate, cuspidate apically, with distinct pale or reddish lateral margins, pilose to lanulose outside; receptacle convex, epaleaceous, with glabrous reticulum. Florets 50–75 or more in a head; corollas reddish, funnelform, with slender basal tube bearing small stipitate glands, throat shorter than lobes, lobes linear-lanceolate, with stiff hairs distally or apically; anther thecae short-acute with small sterile margin at base; apical appendage, oblong-ovate, glabrous, with thin cell walls; style base with narrow annuliform sclerified node; sweeping hairs acicular, at lowest level scarcely extending to top of shaft. Achenes shortly obconic, abruptly narrowed distally to insertion of corolla, 3-6-ribbed, setulae restricted mostly to broad ribs, setulae not split at tips, sides with scattered isolated idioblasts, raphids subquadrate or short oblong in dense inner layer of short to quadrate cells in achene wall; pappus of less than 20 easily deciduous barbellate bristles, bases narrow and weakly attached, distinct outer series not evident. Chromosome number n = 10 (
Pollen ca. 47 μm in diameter in fluid, lophate, triporate, with group of polar lacunae, perforated tectum restricted to muri, bacculae centered at junctures of muri, leaving ogee-shaped gaps under the centers of the muri (Figs
Photographs of
Scanning electron micrographs of acetolyzed echinolophate pollen of
Notable secondary metabolites, eudesmanolide sesquiterpene lactones,
1 | Leaves sessile or subsessile; blades linear to oblong ot ovate-oblong |
|
– | Leaves distinctly petiolate, with petioles to 1.5 cm long; blades ovate |
|
Botswana, Mozambique, Namibia (Caprivi strip), Zambia, Zimbabwe.
Botswana.
Treatment of the genus by
Annual or short-lived perennial herbs, rarely rhizomatous; stems terete and usually striate, with broad solid pith; hairs uniseriate with erect apical cells, with glandular dots. Leaves alternate, sessile or short petiolate; blades thinly herbaceous, ovate to linear lanceolate, base cuneate or continuous onto stem, margins subentire to serrate or dentate, apex acute to obtuse, surfaces glabrous to densely pubescent; venation pinnate with ascending secondary veins. Inflorescence terminal, corymbiform to rather cymiform, lower bracteoles a reduced foliiform, peduncular bracteoles filiform. Heads rather small, with broadly campanulate involucres; involucral bracts 15–40 in 2–3 usually subequal series; receptacle flat or slightly convex, epaleaceous. Florets 3–100 in a head, strongly exserted; corollas white or pink to purple, with glandular dots on surface, with a narrow cylindrical base, limb narrowly funnelform to narrowly campanulate; lobes lanceolate, without apical hairs; bases of anther thecae rounded, not tailed; apical appendages glabrous; style base without node; branches with sweeping hairs shortly acute. Achenes cylindrical with 2–6 usually paler ribs, sides with glandular dots, rarely with short white setulae; raphids short-oblong; pappus lacking or a coroniform rim. Chromosome number n = 10, 20 (
Pollen: ca. 35 μm in diam. in fluid; tricolporate, sublophate, echinate, spines long; tectum continuous in intercolpi and at poles, distinctly microperforate; columellae below spines firmly attached to footlayer (Fig.
Notable secondary metabolites: 5-alkylcoumarins (
Tropical and southern Africa, Asia to China, introduced in Brazil.
Shrubs or small trees, moderately to densely branching; stems mostly terete, with solid pith; hairs of stem often forming a felt, with large often contorted cap cells basally or nearly basally attached. Leaves alternate; petioles short, winged or elongate; blades membranaceous to rather coriaceous, margins entire to serrate or repand dentate, upper surfaces essentially glabrous and somewhat glossy to arachnoid tomentose; secondary veins pinnate, spreading at 30–80° angles, arching nearer margins. Inflorescences terminal, densely corymbiform, with small bracteoles; peduncles short. Heads with campanulate to cylindrical or ovoid involucres; involucral bracts coriaceous to subcoriaceous, appressed, 25–35 in 4–5 gradate series, inner bracts persistent to easily deciduous, outer surface with smooth median shield, without narrow median costa or keel; receptacles epaleaceous. Florets 5–50 in a head; corollas white to violet, basal tube cylindrical, throat longer than the anther thecae or very deeply cut, lobes with glands or spicules on outer surface; anther thecae with base broadly tailed, tails often long; apical appendages glabrous, with rather thick-walled cells; style base without or with scarcely distinct node; style branches with stout, pointed sweeping hairs. Achenes 5–10-costate, with or without setulae, raphids short to elongate, sometimes not evident; pappus of many rather persistent capillary bristles, often with broadened tips, with outer series of short squamellae. Chromosome numbers n = 10, 15, 20 (
Pollen: 30–35 μm in diam. (dry); tricolporate, echinate, sublophate; tectum continuous in intercolpi and at poles, with distinct microperforations; spines long, each with single stout columella below firmly attached to footlayer, intervening perforated tectum scarcely mamillose on inner surface (Fig.
Photographs of
Scanning electron micrographs of acetolyzed pollen of two collections of sublophate echinolophate
Generic limits more restricted than given in
A special effort has been made to resolve the endemic southern African element of
1 | Capitula with 9–30 florets |
|
– | Capitula with 2–5 florets |
|
2 | Leaves sessile, usually auriculate at base |
|
– | Leaves with distinct petioles |
|
3 | Achenes with setulae on the surface |
|
– | Achenes without setulae |
|
4 | Leaf blades elliptical, with sharply serrate margins |
|
– | Leaf blades suborbicular to narrowly obovate, with repand-dentate distal margins |
|
5 | Leaves sparsely puberulous to essentially glabrous abaxially |
|
– | Leaves hispid to tomentose abaxially |
|
6 | Leaf blades chartaceous, with broadly obtuse bases; stems puberulous with often dark hairs |
|
– | Leaf blades rather membranaceous with long-acuminate bases; stems essentially glabrous |
|
7 | Leaf blades oblong to ovate with obtuse bases; stems hirsute; capitula with 3 florets |
|
– | Leaf blades obovate to oblanceolate with cuneate bases; stems tomentose; capitula usually with 4–5 florets |
|
8 | Stems and abaxial surfaces of leaves completely covered with appressed tomentum; inflorescence narrowly corymbose |
|
– | Stems with tomentum of cottony hairs, abaxial surfaces of leaves with mixed erect and arachnoid hairs that do not totally obscure green surface; inflorescence broadly corymbose, much broader than high |
|
The species is used as medicinal plant by both people and animals.
Africa and introduced into Brazil.
Transvaal, Natal, Swaziland, Cape colony.
Tropical and subtropical Africa.
Eastern South Africa through Swaziland and Natal, Transkei, s. Mosambique.
Many specimens from South Africa been seen including Schlechter 6644 distributed under the name
South Africa (Transvaal, Natal, Swaziland, Cape colony).
The species is known in this study from descriptions, from photographs of the syntype, Clydesdale,
Holotype: South Africa. Limpopo Province: Thohoyandou District; Thathe-Vonde Nature Reserve. Grassland at rocky outcrop near entrance, 1233 m,
The type specimen was distributed as
South Africa
West Africa from Guinea and Sierra Leone to Cameroon, Sudan, Ethiopia, Kenya, Uganda, Congo, south to South Africa (Transvaal, Natal), and Swaziland.
Congo and Nigeria east to Uganda, Kenya, Ethiopia, and south to South Africa.
South Africa (Transvaal).
One specimen has been seen, Stalmans 2430AA, from South Africa (Transvaal), that matched the original description in every respect except for the lack of noticeable pubescence on the involucral bracts.
Herbaceous perennials to 1 m tall; stems pilose, hairs unequally T-shaped. Leaves alternate; blades abaxially often densely canescent pilose. Inflorescence laxly to subdensely corymbiform-cymose. Heads short-pedunculate; involucres campanulate, bracts 25–40, in ca. 3–4 series, persistent; receptacle epaleaceous. Florets 12–20 in a head; corollas purple, outside with few to many slightly contorted T-shaped hairs; basal tube funneliform above, throat short, lobes linear; anther thecae not or shortly appendaged at base; apical appendages glabrous, with thin walls; style with basal node; style branches with acicular sweeping hairs. Achenes 4–5-costate, densely setuliferous, setulae scarcely divided at tips, idioblasts numerous, raphids elongate, carpopodia narrowly cylindrical; pappus bristles white, barbate, tenuous, subpersistent, outer series shortly lanceolate. Chromosome number of n = 9, 10, most reports n = 10 (
Pollen grains sublophate, with continuous perforated tectum between colpi, tricolporate to poles, echinate (Fig.
Photographs of
Photographs of
Illustrations
Scanning electron micrographs of acetolyzed pollen from two collections of
Notable secondary metabolites; acetones & sesquiterpene glaucolides/ hirsutanolides (
1 | Leaves mostly basal, not cauline |
|
– | Leaves disposed rather uniformly along stems |
|
2 | Leaf surfaces coarsely pubescent, not sericeous |
|
– | One or both surfaces of leaves sericeous with silvery pubescence |
|
3 | Leaves ovate to ovate-elliptic, 1.5–3 times as long as wide |
|
– | Leaves linear, ca. 2 m wide, 12 or more times as long as wide |
|
4 | Both leaf surfaces densely silvery sericeous; longest phyllaries 5–8.5 mm long |
|
– | Upper leaf surface dark; longest phyllaries 2.3–5 mm long |
|
5 | Larger involucral bracts with caudate apices; capitula less than 1.5 cm wide |
|
– | Involucral bracts acuminate, not caudate; capitula ca. 1.5 cm wide |
|
6 | Leaves acute at base; pubescence on leaf surfaces not obscuring the surfaces, numerous large glandular dots visible on abaxial surface |
|
– | At least upper leaves cordate at base, pubescence on abaxial leaf surface mostly obscuring presence of glandular dots |
|
7 | Bases of lower leaves narrow; tips of phyllaries long-acuminate, equaling or exceeding the pappus |
|
– | Bases of lower leaves cordate; phyllaries without long-acuminate tips equaling or exceeding the pappus |
|
Lesotho, South Africa (Transvaal, Orange Free State, Natal, Cape colony), and Swaziland.
Lesotho, South Africa (Transvaal, Orange Free State, Natal, Cape colony) and Swaziland.
This complete synonymy shows that the oldest name for the species is
Distinguished as a variety from typical
South Africa (Natal).
Lesotho, South Africa (Transvaal, Orange Free State, Natal, Cape colony), and Swaziland.
South Africa (Cape colony, Natal, Transvaal).
Tanzania south to South Africa (Transvaal, Orange Free State, Natal, Cape colony), Botswana, Lesotho and Swaziland.
Mozambique, South Africa (Transvaal), and Swaziland.
South Africa (Natal, Transvaal) and Swaziland.
Perennial herbs; stems with simple multiseptate hairs. Leaves alternate, subsessile to short-petiolate. Inflorescence corymbiform cymes or single heads with short to long peduncles. Involucre funnelform to campanulate; bracts 50–150 in 5–6 series, often pectinate-denticulate with spicules along lateral margins, outer tips often elongate, green and recurved; receptacle epaleaceous. Florets ca. 20–50 in a head; cortollas bluish, tube very long, funnelform near throat; throat very short, lobes apically stiffly pilosulous; anther base rounded; apical appendage glabrous, triangular with thickened ornamentation in center; style base with small annuliform node. Achenes strongly 10-costate, usually with rows of idioblasts or specialized cells along sides of costae, surface setuliferous, setulae slender with pairs of cells not or scarcely separated at tip, raphids subquadrate to short-oblong; pappus of many somewhat persistent long bristles, with outer series short. Chromosome number n = 10 (
Pollen tricolporate, psilolophate, with spur muri intruding into short colpi above and below pore, single polar lacunae often present, not echinate, with or without micropunctations resticted to muri. Muri showing baculae with broadened base, branching distally into many bacula-like branches (Fig.
Most notable secondary metabolites, sesquiterpene germacranolides, elemanolides (
Photographs of
Scanning electron micrographs of
1 | Capitula usually numerous in terminal corymbiform or thyrsiform cymes, peduncles up to 2–3 times as long as the involucre; plants with rather equally leafy stems |
|
– | Capitula on long peduncles, 1 or few in open terminal cymes, peduncles mostly 5 or more times as long as the involucre |
|
2 | Leaves in rosettes, arising from a root-crown; capitula to 2.5–3.0 cm high or wide |
|
– | Slender leaves on short branches, arising from creeping rhizome; capitula mostly 1.2–1.6 cm high or wide |
|
Angola, Burundi, Cameroon, Congo, Malawi, Nigeria, Sudan, Tanzania, Uganda, Zambia, Zimbabwe.
Burundi, Congo, Kenya, Tanzania, Madagascar, south to Angola, Mozambique, and Namibia, South Africa (Transvaal, Natal) and Swaziland.
Botswana.
Small aromatic shrubs to 1.5 m tall; stems, leaves, involucral bracts densely yellowish gray tomentellous or sericeous with crowded T-shaped hairs, hairs with slender 0–2-septate short stalks and small naviculiform or rather elongate cap-cells. Leaves alternate, short-petiolate, with small axillary fascicles usually present, more crowded proximally, smaller distally; blades 5–12 mm long, oblong to obovate, with undulate entire to coarsely dentate margins, basal pair of secondary veins scarcely evident or evident and strongly ascending, minute glandular dots densely disposed on both surfaces. Inflorescences appearing shortly scapose, with numerous pedunculate heads in a corymbiform or partly subumbellate arrangement. Heads campanulate, 6–7 mm wide and high; involucral bracts ca. 60 in ca. 6 strongly gradate series, persistent, oblong ovate with narrow apiculate tips, yellowish with reddish patch or midvein below tip, margins entire, broadly and distinctly thick and pale; receptacle convex, pitted with broad pale network of ridges. Florets 35–40 in a head. Corollas purple, narrowly funnel-shaped from a slender basal tube; throat twice as long as the erect, linear lobes, outer surface of base and throat mostly glabrous, lobes densely glandular-dotted; anther thecae narrow, slightly longer than throat, bases without tails, apical appendages shortly oblong-triangular, glabrous, with thin cell walls; style base with narrow annuliform node; with acicular sweeping hairs almost completely restricted to style branches, a few at top of shaft. Achenes 5-costate, with setulae not divided at tips, surfaces with numerous ungrouped idioblasts, raphids elongate; carpopodium turbinate, glabrous; pappus of ca. 35 slender persistent bristles, bristles as wide at tips as at base, densely scabrid on margins and outer surface, outer series of distinct, smooth, lanceolate scales. Chromosome number unknown.
Pollen ca. 45 μm in diam. in fluid, lophate, triporate, not echinate, perforated tectum restricted or lacking, crests of muri sparsely papillose (Fig.
1 | Leaves oblong, unlobed to few-lobed on lateral margins; secondary veins obscure; tomentellous with crowded minute trichomes bearing minute naviculiform cap-cells |
|
– | Leaves obovate, with numerous lobes distally; acending secondary veins evident; trichomes appearing sericeous, with elongate cap-cells |
|
With habit remarkably like
Namibia.
Thoroughly distinct in appearence, having larger more lobed leaves indicative of more moist habitats.
Namibia.
Low, much-branched shrubs to 1 m high, stems with L-shaped hairs on multiseptate stalks, cap-cells one-armed. Leaves alternate, sub-sessile, linear to elliptical, sometimes serrate. Inflorescences corymbiform cymes, with usually shortly pedunculate heads or with heads sessile in apical clusters of leaves. Involucre ovoid or cylindrical; bracts 20–40 in 4–7 gradate series, ovate to oblong, appressed; receptacle without pales. Florets ca. 10–15 in a head; corollas white or lavender, tubular to narrowly funnelform, throat as long as lobes, tips without hairs or with few short biseriate hairs; anther bases rounded, apical appendages glabrous, with thin-walled cells; style base with narrow ring; style branches with acicular sweeping hairs. Achenes weakly 8-ribbed, sericeous with many setulae, idioblasts numerous, raphids narrowly elongate; pappus biseriate, outer shorter and broader, inner setiform, subplumose, glabrous near base. Chromosome number unknown.
Pollen 7–8-porate, with pores scattered over the whole surface in lacunae that are usually not adjacent, lophate (Fig.
Photographs of
Scanning electron micrographs of
Notable secondary metabolites: sesquiterpene glaucolides (
1 | Stems and peduncles sparsely hispid with short spreading hairs; involucre 6–7 mm wide; involucral bracts with mucronate tip |
|
– | Stems and peduncles subcanescent with appressed hairs; involucre 3–4 mm wide; involucral bracts with obtuse or rounded tips |
|
South Africa (Transvaal, Natal), and Swaziland.
South Africa (Transvaal), and Swaziland.
Subshrubs to small shrubs with erect stems from a woody base, not or sparsely branched between base and inflorescence; hairs T-shaped. Leaves alternate, usually decrescent upwardly, sessile or short petiolate, blades elliptical or ovate to oblanceolate, mostly 4–9 cm long, 2–5 cm wide, base short-obtuse to acuminate, margins scarcely repand-dentate, apex short-acute, upper surface with small spinules and few small hairs, lower surface paler, grayish with slender hairs and partially sunken glandular dots; venation pinnate, with up to six or eight lateral veins each side, spreading at 45–60º angles. Inflorescences with leaves of main axis only somewhat to greatly reduced, with only minute bracteoles on branches. Inflorescence shape broadly corymbiform or cylindrical with rounded to flattened top, with lower heads appearing sessile as result of proliferation by immediately subtending branches forming seriate or scorpioid cymes, branches of inflorescence tomentose with T-shaped hairs. Heads broadly campanulate, 4–14 mm high and wide; involucral bracts mostly persistent, innermost somewhat deciduous, ca. 50–100 in 5–7 series, strongly gradate, 1–8 mm long, 1.0–1.5 mm wide, ovate to oblong, subacute and mucronate to apiculate at tip, innermost acute, tips appressed, margins membraneous and irregularly denticulate distally, often reddish, with dark median keel extending to apex, scarcely thickened and greenish near keel, with numerous small T-shaped hairs except at margins. Receptacle epaleate and tuberculate. Florets 15–ca. 50 in a head; corollas purplish, narrowly funnelform, 4–8 mm long, with sparsely scattered glandular dots, tube slender, 2–3 mm long, throat 1.5–2.5 mm long, lobes 1.0–2.5 mm long, linear-lanceolate, erect, not recurving, sparsely glanduliferous to distinctly or minutely scabridulous outside, without longitudinal internal ducts filling lobe; anther thecae 1–2 mm long, without glandular dots, calcarate and with long tails at base, endothecial cells short usually with 2–3 nodes on transverse walls; apical appendage 0.5–1.0 mm long, narrowly lanceolate, often sharply acute; style base with distinct expanded node; sweeping hairs on style branches and scarcely extending on to upper style shaft, slender and narrowly acute. Achenes 1.5–2.0 mm long when mature, 5-costate, with few to many setulae when young, often glabrous at maturity, often with numerous glandular dots on sides between costae, surface with numerous idioblasts that are not joined in series, with narrowly rhomboid raphids internally; carpopodium stopper-shaped to slightly turbinate, with many series of small thick-walled cells; inner pappus of 25–30 slender capillary bristles, rather flattened outside and barbellate on sides, tips only slightly narrowed, outer pappus of narrow scales 0.5–1.5 mm long. Chromosome numbers n = 10, 18, 20 (
Pollen grains ca. 50 μm in diameter in fluid, type A, sublophate, tricolporate, echinate, with perforated tectum continuous between colpi (Fig.
Scanning electron micrographs of
Most notable secondary metabolites are 5-alkylcomumarins (
The genus is almost alone in the eastern hemisphere in its seriate cymes, often referred to as scorpioid cymes. Such inflorescences are common in the western hemisphere
In Africa in Angola, Botswana, Kenya, Tanzania, Senegal, Uganda, and Zimbabwe; also in western India.
Perennial herbs 0.2–1.0 m tall; from slender prostrate or creeping stem or rhizome, erect stems with few to many ascending branches, five-ribbed, sides with numerous glandular dots, glabrous or finely and sparsely puberulous with some simple multiseptate hairs, and some one-armed L-shaped hairs with stalk near one end as in
Pollen ca. 50 μm in diam., sublophate, echinate (Type A), tricolporate, sub-echinolophate (Fig.
Most notable secondary metabolites, sesquiterpene nerolidol derivatives (
Photographs of
Scanning electron micrographs of acetolyzed sublophate-echinolophate pollen grains of two collections of
1 | Stems, abaxial surfaces of leaves and peduncles with whitish puberulence; pale margins of involucral bracts usually without scarious border, rather evenly tapering into base of awn; achenes hispid with short spreading setulae |
|
– | Stems, abaxial surfaces of leaves and peduncles without whitish hairs; pale margins of involucral bracts usually with expanded scarious border, mostly not evenly tapering into base of awn; achenes sericeous with long setulae |
|
Namibia, South Africa (Transvaal), and Zimbabwe.
South Africa (Natal).
Some species of the genus are treated by
Mostly annuals; stems with L-shaped hairs bearing elongate one-armed cap-cells. Leaves alternate. Inflorescence a thyrsoid panicle with corymbiform cymose branches bearing pedunculate heads or a single terminal head. Involucral bracts ca. 80 in ca, seven series, often with widely scarious margins and awns often black at tips; receptacles epaleaceous. Florets ca. 30 in a head; corollas whitish to purplish, basal tube long, narrowly funnelform distally, throat as long as the narrow glabrous lobes; anther bases plain, not tailed; apical appendage glabrous, with thin cell walls, sometimes weakly ornamented; style base with distinct annular node; branches with acicular sweeping hairs. Achenes 5 or 8–10-ribbed, setuliferous with setulae scarcely divided at tips, idioblasts present but not grouped, raphids elongate; pappus with copious barbellate setae, greenish, yellowish or tawny, rarely white, outer pappus short, squamiform. Chromosome number n = 9, 10 (
Pollen lophate with ca. 32 lacunae, with five or more pores that seem to be rather asymmetrically distributed on the grains; the pores occur in lacunae that, in a few cases, are adjacent; margins of muri minutely echinate to psilate, without micropunctations, baculae closely spaced in single evenly spaced row under each murus, baculae in turn subtended by “rhizomate” structure that is weakly attached to the footlayer, the muri thus easily stripping away from the footlayer (Fig.
Notable secondary metabolites: sesquiterpene lactone glaucolides/hirsutanolies (
Scanning electron micrographs of
1 | Base of the involucre with slender lanceolate bracts, bracts with straight or flexuous apical awns |
|
– | Base of involucre with broad, ovate or oblong bracts, bracts with or without apiculus or mucro |
|
2 | Tips of involucral bracts erect, mostly without distinct apiculate or mucronate apices |
|
– | Tips of involucral bracts often with recurved or squarrose apiculate apices |
|
Tanzania, Mozambique and Natal east to Malawi, Zambia and Zimbabwe.
Angola, Botswana, Namibia, South Africa (Transvaal), and Zimbabwe.
South Africa (Transvaal), Swaziland.
Small perennial herbs; stems erect, with short branchlets from lower nodes, puberulous to subsericeous with short-stalked hairs bearing asymmetric cap cells, stalks moderately broad with one or two septae, cap cells short and stout, attached near lower end. Leaves alternate, oblong to linear, essentially sessile, sparsely puberulous, abaxially densely glandular punctate. Inflorescence terminal with 1 or a few heads borne on long peduncles. Heads campanulate, 1.7–2.5 cm. wide; involucral bracts 20–60, in ca. three series, subequal, linear-lanceolate, herbaceous with slender tips, pilosulous outside; receptacle slightly convex, surface with angular thickenings. Florets 15 or more in a head; corollas purple, ca. 1 cm long, narrowly funnel-shaped from a slender base, throat slightly shorter than the moderately distorted, linear-lanceolate lobes, outer surface with short glands on tube and throat, spiculiferous distally on lobes; anther thecae narrowed at base to short lobulate tail; apical appendage glabrous, ovate with rather firm cell walls; style base with narrow annular node; sweeping hairs acicular, restricted mostly to style branches, few on upper shaft. Achenes mostly 6–8-ribbed, to 4.5 mm long, with glandular punctations and scattered idioblasts on sides, rarely without or with many short setulae that are not or scarcely split at apex, inner layer without raphids or with subquadrate raphids, with layer of rather sclerified narrow cells appearing as striations under the glands and idioblasts; carpopodium broadly stopper-shaped, sometimes with few short uniseriate hairs on inner surface; pappus of ca. 40 scabrid bristles, mostly in one series, as long as tube and throat of corolla, rather easily deciduous, scarcely narrowed except at tips, with few indistinct short bristles in outer series. Chromosome number unknown.
Pollen ca. 47 μm in diam., tricolporate, sublophate, echinate, with perforated tectum continuous between colpi (Fig.
Photographs of
Scanning electron micrographs of
Most notable secondary metabolites include sesquiterpene glaucolides (
The genus consists of mostly monocephalous species, but those species have many individual differences such as the restriction of leaves to a basal rosette, capitula structure, and pubescence of the achenes. They do have essentially identical pollen, but it is a widely distributed pollen type in the
1 | With numerous cauline leaves; heads with many linear outer involucral bracts; achenes with few or no setulae; setulae not divided at tips |
|
– | With leaves mostly basal; heads without linear outer involucral bracts; achenes with many setulae; setulae with shortly but distinctly divided tips |
|
South Africa (Transvaal, Natal).
The older De Candolle name has been placed rather consistently in synonymy, but not adopted. It is only comparatively recently that the combination was occuppied in
Zambia, Transvaal (
The specimen cited by
It is evident from the description that
. Annual or perennial herbs 0.3–1.0 m tall; stems pilose, hairs simple with elongate apical cells with slightly asymmetric bases. Leaves alternate. Inflorescence with 1–many heads. Involucre campanulate; involucral bracts ca. 50 in ca. three series, gradate, persistent; receptacle epaleaceous. Florets ca. 50 in a head; corollas reddish-purple, basal tube narrowly funnelform, throat shorter than lobes or anther thecae, lobes pilosulous distally; anther bases acuminate to acutely tailed; apical appendage glabrous, with thin cell walls. Style base with node; style branches with acicular sweeping hairs. Achenes 4–6-angled, setulae aparse on sides, idioblasts usually grouped in transverse bands, raphids elongate; pappus bristles subpersistent, marginally densely barbellate; outer squamae persistent. Chromosome number n = 10 (
Pollen triporate, lophate, perforated tectum discontinuous in lacunae, muri papillate, with or without micropunctations on muri (Fig.
Scanning electron micrographs of
With habit similar to
1 | Perennial herbs |
|
– | Annual herbs |
|
2 | Apices of involucral bracts straight |
|
– | Apices of involucral bracts recurved |
|
Tanzania, Mozambique, Zimbabwe.
Angola and Congo east to Mozambique and Tanzania, Namibia.
West Africa east to Tanzania, Mozambique, Zimbabwe, Natal.
Species reviewed by
Annual or perennial herbs, with leaves rosulate or on leafy stems, basal rosettes often withered at anthesis, bases of plants erect, with or without a dense basal cloak of hairs. Hairs simple or lacking on stems. Inflorescences monocephalic, laxly cymose or densely corymbiform, with short to very elongate peduncles. Heads broadly campanulate; involucres 3–6-seriate, bracts broadly to narrowly oblong, gradate with basal bracts often more lanceolate, tips of inner bracts often obtuse to rounded or apiculate, distally and marginally rather scarious, often purplish. Florets 10–50 or more in a head; corollas purple, with long slender basal tube, throat short, not noticeably broadened at base, lobes linear, usually contorted with age, bearing glands, simple hairs, or L-shaped to T-shaped hairs; anther thecae calcarate and blunt at base, without tails; apical appendage oblong-ovate, with thin cell walls; style base with annulus of thickened, quadrate cells; sweeping hairs slender with sharp, narrow tips. Achenes with ca. 10 ribs, setulose on ribs, setulae with paired cells separated in distal third or less, with numerous idioblasts on surfaces between ribs; raphids in achene wall narrowly elongate. Chromosome number n = 9 (
Pollen ca. 30–40 μm in diameter when dry, tricolporate with short or truncated colpi, sharply echinate with elongate spines, sublophate with large irregularly shaped lacunae, perforated tectum continuous in lacunae (Fig.
Notable secondary metabolites include sesquiterpene lactones (elemanolides and eudesmanolides).
The genus
Natal.
Material of the species was sought by Smith from its type locality, but he reported (1971), “I searched the type locality for living plants, but the area is now devoted to sugarcane fields, and the species may have been completely eliminated.”
Congo, Angola, Namibia (Caprivi strip), Zambia.
The initial assumption, based on the robust habit and the described yellowish brown velutinous pubescence of the stems, was of a relationship to the genus
An examination of limited fragments showed a few additional characters. The abaxial surface of the leaf has a tomentum of long-armed T-shaped hairs and sweeping hairs restricted to the branches of the style and the juncture of the branches at the shaft of the style. The lobes of the corolla had areolae that were reminiscent of the ducts in the corolla lobes of true
Illustration of
Transvaal (In cliv. Mont. Elandspruitbergen, alt. 7000 ped., leg. R. Schlechter, 2 December 1893, N. 3832).
The name is an illegitimate later homonym and cannot be used, but the species, as described, cannot be placed with other Vernonian species presently known from South Africa. The original description (
M. Koekemoer (
As a general rule
A. Blittersdorff R von (2009) “
B. Hyde M (2014) “
C. Hyde M (2014) “
D.
A. Smith CE, Jr (1971) ”
B. Prain D (1918) “
C. Anonymous (1832). “
D. Robinson H, Funk VA (2014)
A–C. LeBourgeois T (2008) “
A–C. Wursten BT (2014) “
D. Creative Commons - Attribution Non-Commercial Share-Alike.
E–F. English P (2010) “
G. Graham G (2013) “
H. Anonymous (2012) “
A–B. Schneider B (2013) “
C–D. Wursten BT (2014) “
E. Bidault, E. (2015) “
A. Villiers F de (2014) “
B–D. Berkel, N van (2013) “
A–B. Blittersdorff R von (2008-9) “
C–D. Warren PR (2013) “
A–D Berkel N van (2012) “
Hooker WJ (1863) “
Humbert H (1960) Composees. “
Wood JM (1906) “
Wood JM (1906) “
A–B. Dressler S, Schmidt M, Zizka G (2014) “
C–D. Strohbach B (2014) “
A–B. Taylor R (2014) “
C. Wursten BT (2007) “
D–E. Dreyer, A. (2015). “
A–C. Warren, P.R. (2014) “
D–F. Wursten, B.T. (2014) “
A. Hankey A (2013) “
B–C. Blittersdorff R von (2008) “
D–E Warren PR (2013) “
F–G. Wursten BT (2010) “
A. Wildeman E, Durand T (1898) “
† Deceased