Solanum africanum Mill., Gard. Dict. ed. 8, no. 26. 1768.

Knapp, Sandra & Vorontsova, Maria S., 2016, A revision of the " African Non-Spiny " Clade of Solanum L. (Solanum sections Afrosolanum Bitter, Benderianum Bitter, Lemurisolanum Bitter, Lyciosolanum Bitter, Macronesiotes Bitter, and Quadrangulare Bitter: Solanaceae), PhytoKeys 66, pp. 1-142 : 25-28

Solanum africanum Mill., Gard. Dict. ed. 8, no. 26. 1768. Figures 1A , 3

Solanum quadrangulare Thunb. ex L.f., Suppl. 147. 1781. Type. South Africa. Western Cape: " CBS [Caput Bona Spei]", P. Thunberg [476] (lectotype, designated here; LINN [LINN 248.26]).

Solanum crassifolium Lam., Tabl. Encycl. 2: 16. 1794. Type. Based on Dillenius, Hortus Elthamensis 365, t. 273. 1732 (lectotype, designated here: Dillenius, Hortus Elthamensis 365, t. 273. 1732)

Witheringia crassifolia (Lam.) Dunal, Hist. Nat. Solanum 108. 1813. Type. Based on Solanum crassifolium Lam.

Solanum bracteatum Thunb., Act. Gorensk. [Fl. Cap. 2: 57]. 1818. Type. South Africa. No specimens found.

Solanum aggerum Dunal, Prodr. [A. P. de Candolle] 13(1): 103. 1852. Type. South Africa. Western Cape: "Cape, in oasis Zitzikania", P.P.S. Krauss s.n. (holotype: G [G00301688]; possible isotype: MO [MO-1811850]).

Solanum exasperatum Drège ex Dunal, Prodr. [A. P. de Candolle] 13(1): 104. 1852. Type. South Africa. KwaZulu-Natal: "in frutecetis haud procul a maris littore, inter Umcomas [Unkomaas] et Natal", Drège, J.F. s.n. (holotype: G-DC [G00145074]; isotype: MPU [MPU011259]).

Solanum geniculatum Drège ex Dunal, Prodr. [A. P. de Candolle] 13(1): 105. 1852. Type. South Africa. KwaZulu-Natal: "in frutecetis inter Umsamculo et Omcomas [Unkomaas], haud procul a maris littore (V, C)", Drège, J.F. s.n. (holotype: G-DC [G00145049]; isotype: K [K000414161]).

Solanum longipes Dunal, Prodr. [A. P. de Candolle] 13(1): 85. 1852. Type. South Africa. KwaZulu-Natal: Natal, "locis natalis incestus", Drège, J.F. s.n. (holotype: G-DC [G00144869]).

Solanum quadrangulare L.f. var. integrifolium Dunal, Prodr. [A. P. de Candolle] 13(1): 77. 1852. Type. South Africa. Western Cape: Stellenbosch, J.F. Drège s.n. (holotype G-DC [G00144675]; isotype: K [K000414165]).

Solanum quadrangulare L.f. var. sinuato-angulatum Dunal, Prodr. [A. P. de Candolle] 13(1): 77. 1852. Type. South Africa. Western Cape: between Cape Town and Stellenbosch, J.F. Drège s.n. (holotype: G-DC; isotype: K [K000414162]).

Solanum quadrangulare L.f. var. glabrum Dammer, Bot. Jahrb. Syst. 38: 179. 1906. Type. South Africa. Western Cape: "sudwestliches capland: Riversdale, Rust 430, 484 " (type at B [?]; no duplicates found of either collection).

Solanum quadrangulare L.f. var. crassifolium (Lam.) Bitter, Bot. Jahrb. Syst. 54: 431. 1917. Type. Based on Solanum crassifolium Lam.

Type.

" Solanum dulcamarum Africanum, foliis crassis hirsutis", cultivated in England, at James Sherard’s garden in Eltham (Hortus Elthamensis) in 1726, originally from South Africa, Cape of Good Hope, Anonymous s.n. (lectotype, designated here: Dillenius, Hortus Elthamensis 365, t. 273. 1732). " Solanum Afric., frutescens, foliis angulatis, crassis et hirsutis, fl. caerulei. H. Eltham 1726" (epitype, designated here: OXF [Dill-HE 273-352, sheet 1]) .

Description.

Scrambling vine to shrublet, 0.5-2 m. Stems strongly 4-winged, the wings less prominent on older stems, glabrous, minutely papillate or sparsely to moderately pubescent with antrorse simple uniseriate trichomes to 0.5 mm long, these arising from a multicellular base and deciduous, leaving the base and the stems apparently toothed; new growth glabrous or minutely papillate especially on leaf margins. Bark of older stems pale yellowish brown. Sympodial units plurifoliate, the leaves not geminate, evenly distributed along branches. Leaves simple or shallowly lobed, (1)2-5.2 cm long, (0.6)0.9-2.5 cm wide, elliptic to narrowly elliptic, thick and fleshy, both surfaces glabrous; major veins 3-4 pairs, not easily visible, the finer venation not visible; base cuneate and decurrent onto the stem; margins entire or with up to 3 shallow lobes, pubescent with antrorse uniseriate trichomes from broad bases like those of the stems giving an appearance of minute teeth, revolute in herbarium specimens; apex acute to slightly rounded-acute; petiole indistinct, if discernible to 1 cm with a narrow wing of leaf tissue along entire length. Inflorescences terminal, 1-10 cm long, 2-4(6) times branched, with 10-30 flowers, glabrous or with scattered bulbous-based simple uniseriate trichomes <0.5 mm long; peduncle 0.5-2.5 cm long, sometimes purple as are the pedicels; pedicels 0.8-1.2 cm long, ca. 0.5 mm in diameter at the base, ca. 1.5 mm in diameter at the apex, nodding or spreading at anthesis, glabrous or sparsely pubescent with simple uniseriate trichomes <0.5 mm long, articulated at or near the base, leaving a tiny raised peg ca. 0.5 mm in the inflorescence axis; pedicel scars irregularly spaced in clumps. Buds globose becoming ellipsoid before anthesis, strongly exserted from the calyx tube long before anthesis. Flowers 5-merous, apparently all perfect. Calyx tube 1-1.5 mm long, openly cup-shaped, the lobes 1-1.5 mm long, deltate, fleshy and sometimes dark purple, the margins thickened in dry material, with a tuft of simple uniseriate trchomes at the tip, these ca. 0.25 mm long, yellowish when dry. Corolla 1.2-1.6 cm in diameter, violet-blue, stellate, lobed ¾ of the way to the base, the lobes 6-6.5 mm long, 2.5-4 mm wide, spreading at anthesis, glabrous adaxially, densely pubescent or papillate abaxially on the tips and margins, the trichomes <0.2 mm long. Stamens equal; filament tube absent; free portion of the filaments 1-1.5 mm long, minutely papillate at the base adaxially; anthers 2.5-3 mm long, 1-1.5 mm wide, ellipsoid, loosely connivent, bright yellow, smooth abaxially, poricidal at the tips, the pores lengthening to slits with age, the tips paler and thickened in dry material. Ovary globose, glabrous; style 5.5-6.5 mm long, glabrous, apparently exserted from the bud before anthesis; stigma capitate, the surface minutely papillate. Fruit a globose to ellipsoid berry, 0.7-0.8 cm in diameter, purplish black when mature, juicy, the juice purple, the pericarp thin and shiny; fruiting pedicels 1.1-1.3 cm long, ca. 1 mm in diameter at the base, somewhat woody (?), nodding or spreading; fruiting calyx lobes slightly reflexed. Seeds 6-10 per berry, ca. 3 mm long, ca. 2.5 mm wide, flattened reniform with thickened margins, rusty brown, the surfaces minutely pitted, the testal cells pentagonal in outline.

Distribution

(Figure 4 ). Endemic to the coastal region of South Africa (most commonly collected in Eastern and Western Cape provinces, a few collections from North West, Gauteng and KwaZulu-Natal provinces).

Ecology and habitat.

Dunes and strand habitats near the sea; 0-50 m elevation.

Common names and uses.

South Africa: dronkbessie (SANBI, http://www.ispotnature.org/species-dictionaries/sanbi/Solanum%20africanum).

Preliminary conservation status

( IUCN 2014). Least Concern (LC). EOO 62,716 km2 (LC), AOO 36 km2 (EN). Solanum africanum is widely distributed along the southern part of South Africa, and although the AOO calculated here indicates some conservation concern, this is in part due to the releatively low number of specimens we have examined. The species occurs in several protected areas, and is likely to be more common than our data suggest.

Discussion.

Solanum africanum was recognised by Linnaeus as part of his Solanum dulcamara L. It is superficially similar to that species, but differs in its ellipsoid, rather than tapering, anthers (see Knapp 2013), its purple berries and in its strongly angled stems (Fig. 1A ). It is sympatric with and could be confused with Solanum guineense , but the branched inflorescence with smaller flowers distinguish Solanum africanum . The fruits of Solanum guineense are orange when ripe. Leaf shape and pubescence vary a great deal throughout the range of Solanum africanum ; plants from drier habitats near the sea appear to have fleshier leaves, but pubescence does not seem to be environmentally influenced. Juvenile leaves appear to have more deeply incised margins, but some flowering specimens also have incised leaves.

Miller (1768) coined the binomial Solanum africanum as a replacement at the species level for Linnaeus’ variety of Solanum dulcamara "β Solanum dulcamarum africanum , foliis crassis hirsutis" ( Linnaeus 1753), correctly recognising its distinctness. The only flowering material either author cited was the illustration (Fig. 3 ) from Dillenius (1732), although it is clear that Miller grew the plant at Chelsea and knew it from live material, at least vegetatively. He states clearly its differences to Solanum dulcamara - "some who have supported this and our common nightshade to the be same, which is certainly a great mistake, for this sort will not live abroad [outside] through the winter in England in any situation, nor does it produce flowers here with any treatment, for there are plants in the Chelsea Physic Garden of several years old, which have been differently managed, and yet have never flowered." None of the four sheets in the Sherard herbarium at OXF match the plate from Hortus Elthamensis ( Dillenius 1732) exactly (as is often the case, see Solanum campechiense L., Knapp and Jarvis 1989); the plate seems to combine some elements from several of the sheets at OXF, or may have been drawn from live plants. Two are sterile branches, and two bear one flowering branch each in addition to a sterile branch with juvenile leaf morphology. The epitype we have selected is the sheet dated "H. Eltham 1726" with one branch whose inflorescence mostly closely matches that in the plate (Dill-HE 273-352, sheet 1) and that bears the date 1726.

Solanum quadrangulare , the name by which this plant was long known, was the name coined for this species by Carl Peter Thunberg, Linneaus’ pupil who collected extensively in South Africa. It refers to its quadrangular stems. We have selected the sheet in the herbarium of the Linnean Society of London (LINN 248.26) as the lectotype of this name; it has an annotation in Linneaus’ handwriting and a reference to Thunberg ("T 476/ CBS").

Solanum crassifolium was based on the same Dillenius (1732) illustration as Solanum africanum , and we consider the names homotypic.

Thunberg’s species Solanum bracteatum first appears to have been effectively published in 1818, in his Flora Capensis ( Thunberg 1818). In that work he refers to "Act. Gor." that is probably an earlier place of publication (in the entry for Solanum quadrangulare he refers to "Acta Gor. 1812"). This is a reference to the botanic gardens of Count Alexis de Razumovsky at Gorenki, just outside Moscow, whose director was Friedrich E.L. Fischer, who later went on to be director of the botanic gardens in St. Petersburg. We have been unable to find an 1812 publication attributable to the “Société Phytographique de Gorenki", nor is Solanum bracteatum listed among the plants grown at Gorenki at that time ( Fischer 1812). Fischer also edited the Mémoires de la Société Impériale des Naturalistes de Moscou, and in the preface to volume 5 ( Fischer 1817) refers to the first four volumes of the Mémoires being consumed by flames, presumably during the Napoleonic sack of Moscow, and the fusion of the Gorenki society with that of Moscow ("Les Mémoires de la Société Impériale des Naturalistes de Moscou consistant en quatre volumes, avoient, à la catastrophe de 1812 les sort de tant d’autres objects d’être consumes par les flammes. Il m’a paru important de faire paroître aussitôt de possible les matériaux qui se sont depuis rassemblés et qui, apres la réunion de la Société phytogeographique de Gorenki à la nôtre, sont devenus si intéressans pour la botanique - et de recommencer l’impression d’un ouvrage brûlé….”). An article by Thunberg (1817) in the same volume of the Mémoires does not include Solanum bracteatum , nor any references to "Act. Gor." It is possible (and seems to us probable) that the original Thunberg publication scheduled for publication in 1812 never appeared in print, and thus this name is effectively published only in the Flora Capensis of 1818 ( Thunberg 1818). The 1812 publication may, however, turn up, and that then would be the correct date of publication of Solanum bracteatum . We have found no specimens or other original material for Solanum bracteatum . Thunberg (1818) distinguished Solanum bracteatum from Solanum quadrangulare by its bracteate, less-branched inflorescences, but the branched inflorescence and black fruit clearly indicate it is a synonym of Solanum africanum , rather than Solanum guineense .

Dunal (1852) described a variety of taxa at both the species and subspecies level that we consider synonymous with Solanum africanum . Solanum aggerum was described from a specimen collected at “Zitzikania” in 1839 held in "herb. Boiss."; a specimen at MO with the locality "Goukania, Feb" is possibly an isotype. These all represent leaf shape and pubescence variants of Solanum africanum . We have been unable to trace any duplicate material of the two collecctions cited by Dammer (1906) in the protologue of Solanum quadrangulare var. glabrum (Rust 430, 484); these specimens were likely to have been destroyed in Berlin.

Selected specimens examined.

South Africa. Eastern Cape: Thornhill, 5 miles W, Dist. Port Elizabeth , 27 Apr 1947, Acocks 13666 (K); Bushman's River Mouth , left hand bank from sea, Oct 1973, Arnold 594 (K); Baviaans Kloof , 3 Jun 1976, Bayliss 7484 (G); Port Elizabeth , near the Block House , 13 Dec 1813, Burchell 4342 (K); Port Elizabeth , at Cape Recife , 24 Dec 1813, Burchell 4389 (K); Van Staden's River , near the ford ( Uitenhage Division ), 9 Feb 1814, Burchell 4668 (K, LE); Kowie , Dist. Bathurst [Kowie River?], Aug 1929, Dyer 2010 (K); Slang River , Div. Humansdorp , Mar 1922, Fourcade 2178 (K); Kahoon River , near river mouth, Div. East London , 15 Apr 1900, Galpin 2690 (K); Alexandria forest , 28 Apr 1931, Galpin 10687 (BM,K); Uitenhage , 33°46' S, 25°24' W, Jan 1899, Haagner s.n. (K); Boknesstrand, Richmond, Dist. Alexandria, 20 May 1954, Johnson 930 (K); Port Elizabeth , 1894, Laidley & Co. 274 (G); Tzitzikama Park, Storm's River mouth near beach, Dist. Humansdorp, 30 Jan 1966, Liebenberg 7861 (K); Sea View, 16 Mar 1931, Long 395 (K); Quora mouth, 25 Mar 1973, Strey 11187 (E, K); Klipdrift, Div. Humansdorp, May 1860, Thode A-2494 (K); Bathurst, Kowie W., May 1914, Tyson s.n. (G); Alexandria Forest Station , Dist. Alexandria, 26 Feb 1986, Wells 2780 (K); Uitenhage, Zeyher 75 (K) . KwaZulu-Natal: Umzimkulo River, Drège s.n. (K); Uvongo Beach , Port Shepstone region , Apr 1968, Liebenberg 8120 (K); Illovo, lower Illovo [River], 4 May 1894, Medley Wood 6390 (BM, E, K); Umdloti, 23 Feb 1969, Ross 1991 (EA, K) . North West: Zwartkopsrivier, in valley and surrounding hills from Villa Paul Mare to Uitenhaag, Ecklon & Zeyher s.n. (CAS) . Western Cape: Riversdale, playas y dunas de Witsand, 20 Jan 2008, Aedo et al. 18685 (MA); Strandfontein, 19 Jun 1956, Baker 1001 (BM); Kynsna, 4 May 1963, Bayliss 1402 (G); Bilou River, Knysna District , Mar 1910, Fourcade 626 (K); Gordan's Bay , 16 Apr 1914, Garside 484 (K); Grootbos Forest , Stanford, E of Hermanus, 2 Feb 1982, Hepper 7320 (K); Cape Agulhas, southernmost tip of Africa, 2 Feb 1982, Hepper 7321 (K); Bredasdorp de Hoop , edge of lake at south end of nature reserve, 3 Feb 1982, Hepper 7323 (K); Muizenberg, Diep River , prope Muizenberg, Mar 1899, MacOwan 1930 (BM, G, K); Cape of Good Hope , Nelson s.n. (BM); Strand, Stellenbosch Division, 26 Feb 1942, Parker 3652 (K); Mossel Bay , near Klas Meyer’s, Aug 1847, Prior s.n. (K); Strand, Hottentots Holland, Jan 1880, Rogers s.n. (K); False Bay , prope Muizenberg, 3 Apr 1892, Schlechter 640 (G); Muizenberg, by railway, 11 Mar 1896, Wolley-Dod 1018 (K); Walk Bay , near Capetown, Mar 1910, Worsdell s.n. (K) .

Figures

Figure 1. Flowers of species in the ANS clade. A Solanum africanum Mill. (South Africa, Rebelo s. n. - no herbarium voucher) B Solanum imamense Dunal (Madagascar, Rakotavao 5128) C Solanum madagascariense Dunal (Madagascar, Vorontsova et al. 498) D Solanum sambiranense D'Arcy & Rakot. (Madagascar, Randrianasolo 580) E Solanum terminale Forssk. (Kenya, Vorontsova et al. 93) F Solanum truncicola Bitter (Madagascar, Antilahimena et al. 7846). Photo credits: A Tony Rebelo; B Charles Rakotavao; C, E Maria Vorontsova; D Richard Randrianasolo; E Patrice Antilahimena.

Figure 3. Solanum africanum Mill. Lectotype of Solanum africanum " Solanum Afric., frutescens, foliis angulatis, crassis et hirsutis, fl. caerulei H. Eltham 1726 " from Dillenius, Hortus Elthamensis 365, t. 273. 1732. Reproduced with permission of the Natural History Museum Library.

Figure 4. Distribution of Solanum africanum Mill.