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  1. Family: Solanaceae Juss.
    1. Genus: Solanum L.
      1. Solanum arundo Mattei

        This species is accepted, and its native range is Ethiopia to Tanzania.

    [FTEA]

    Solanaceae, Jennifer M Edmonds. Oliganthes, Melongena & Monodolichopus, Maria S. Vorontsova & Sandra Knapp. Flora of Tropical East Africa. 2012

    Type
    Type: Somalia, Mogadishu, Macaluso 82 (PAL, holo.)
    Habit
    Shrub or small tree to 5 m high, often much-branched, with reddish smooth flaking bark; young stems densely whitish-pubescent with sessile or shortly (–0.2 mm) stalked stellate hairs to 0.5 mm diameter with erect median rays and ± 8 equal eglandular rays to 0.2 mm long, glabrescent; simple glandular hairs often also present throughout; main stems and branches with sharp pyramidal downwardly recurved prickles, 5–8(–14) × 6–8 mm basally
    Leaves
    Leaves alternate or opposite, usually dark green on both surfaces, shiny, sometimes rough, broadly ovate, rarely lanceolate, 1.1–5(–7) × 0.7–3.8(–6.5) cm, bases cuneate, margins repand or sinuate with 0–3 deep or shallow obtuse lobes on either side, apices usually obtuse; both surfaces stellate-tomentose to glabrescent, the hairs to 0.8 mm diameter with up to 12 equal rays 0.2–0.3 mm long, below usually denser on the midribs and main veins, always with straight acicular yellow prickles to 19 × 1.2–3 mm on both midribs, sometimes smaller ones also present on main veins; petioles 0.1–1 cm long, occasionally with straight acicular prickles
    Inflorescences
    Inflorescences terminal to lateral, few–16flowered simple or forked to multiply-branched, lax, racemose or scorpioid cymes, often with basal pedicel arising at or near junction with stem
    Flowers
    Flowers usually 5-(–6)merous; axes initially white stellate-tomentose, becoming woody and glabrescent; peduncles erect, 0–13 mm long in flower and fruit; pedicels erect to recurved and 4–11 mm long in flower, strongly recurved and 7–14 mm in fruit, with an occasional pyramidal prickle
    Calyx
    Calyx white to green, campanulate/cupulate, (4–)6–10 mm long, stellate-tomentose on tube externally, with acicular prickles on lobes and veins of tube; lobes often unequal, narrowly triangular to ovate, becoming strongly recurved between corolla lobes, (3–)4–7 × 2.5–5 mm, acute to apiculate; adherent basally in fruit, becoming reflexed, 4–10 × 3–8 mm, glabrescent, often with small acicular prickles
    Corolla
    Corolla blue to purple, occasionally white, often with a prominent internal veining, deeply stellate, 2–3.4 cm diameter, tube 1–2 mm long, glabrous; lobes obovate, ovate or lanceolate, 5–14 × 2.5–5 mm, acute, often with inrolled margins, stellate-tomentose externally and on veins, margins and lobe apices internally, strongly reflexed after anthesis
    Stamens
    Stamens usually equal; filaments free for 0.5–1.8 mm, glabrous; anthers bright yellow to orange, poricidal, 5–7(–8) × 0.9–2 mm basally, curved to connivent
    Ovary
    Ovary 0.9–3 × 0.8–2.5 mm, stellate-pubescent, densely pilose around junction with style, 2–4-locular; style often S-shaped, 9–14 mm long in hermaphrodite flowers, stellate-pubescent in lower part, exserted up to 7 mm, 1.8–5.8 mm long in ‘male’ flowers with the long median rays of the stellate hairs often forming a sheath around the stylar base and upper ovary; stigma clavate, occasionally bi-lobed or sinuate, 1–1.8 × 0.5–1.2 mm in hermaphrodite flowers, and 0.4–0.8 × 0.3–0.6 mm in ‘male’ flowers
    Fruits
    Berries rough, mottled or striped green and cream when immature, finally yellow, dull, globose to spheroid with thick (0.3–2 mm) tough pericarp, 1.2–2.8 × 1.5–3.5 mm, ± glabrous
    Seeds
    Seeds > 100 per berry, smooth, light to dark brown, obovoid to orbicular, occasionally reniform, 1.8–3.2 × 1.6–2.5 mm, not flattened, shallowly punctuate/verrucate; sclerotic granules usually absent
    Figures
    Fig 26/1–8, p 217
    Ecology
    Acacia or Acacia-Commiphora bushland, Acacia-Balanites wooded grassland, scattered tree grassland, thickets, grassland, semidesert, abandoned cultivations and disturbed or heavily overgrazed land, on lava rocks, ant-hills, bare slopes and riverine banks; 300–2150 m
    Note
    Many herbarium specimens of S. arundo lack leaves – though they often include leaf fragments; they seem to become brittle on drying. Plants of this species can form pure stands or large colonies and are considered invasive in Somalia. They tend to form impenetrable barriers, and are used for hedging in T 5. The berries are eaten by camels and goats in Somalia, though they are reported to be bitter and not eaten in K 1 where, however, elephants are reportedly fond of the plant. Verdcourt & Trump (Common Poisonous Plants for East Africa, 1969) noted that there was a record of S. arundo being used to procure a miscarriage; though this tragically resulted in the woman dying 48 hours later, there was no mention of the plant part used. However, the species is also listed as a medicinal plant in tropical Africa in PROTA 11: 308 (2002). The placement of Dammer’s S. diplacanthum is difficult in the absence of extant type material. Most of the leaf characters cited in the protologue are analogous to those found in S. arundo, except that Dammer described the margins as entire or rarely smoothly repand – features more typical of S. dennekense. Later, however Bitter (1923) described the margins as usually sinuate-repand with 2–3 lobes. Since he presumably made his description from Fischer’s holotype in Berlin, this species is considered to be synonymous with S. arundo. All other features cited in the protologue agree with those typifying S. arundo. Standleys’ S. helleri is undoubtedly synonymous with S. arundo; most features described in the protologue are identical with the exception of the inflorescence structure which was described as solitary, paired or few-flowered racemose cymes. However, the type specimen seems to be part of a mature lower stem fragment; younger stems apices would probably have borne branched and several-flowered immature inflorescences. Bitter (in F.R. 16; 142, 1923) thought that his new section Ischyracanthum was composed of a small group of shrubs, ± restricted to Somalia, which stood between the sections Oliganthes and Andromonoecum. He considered that the prickle morphology and small leaves in the three species S. ogadense Bitter, S. dennekense Dammer and S. diplacanthum Dammer were so distinct from all other African Solanums that their separation into a new section was necessary. Whalen (1984) considered this to be an unusual species complex without any clear relatives either in Africa or elsewhere. Jaeger (1985) thought the andromonoecious flowers and yellow fruits were suggestive of section Melongena species, though the tough pericarp was a unique character not found in any other African Solanums. Many authors have reviewed andromonoecy in Solanum, including Whalen & Costich (in D’Arcy (ed), Solanaceae Biology & Systematics: 284–302 (1986)). Although this term strictly refers to both hermaphrodite and male flowers occurring on the same plant – the two sect. Ischyracanthum species dealt with here could more accurately be described as heterostylous – all flowers have well-developed anthers and all the ovaries examined had similar sized and shaped ovules. The styles however differ in length, with those from the more distal areas of the plant being sometimes (but not always) short and enclosed within the anther cone, while the majority are long and exserted. The protologues of two of these species and their descriptions in floras (e.g. Friis 2006) only give the characteristics of the hermaphrodite flowers. Bitter (1923) did however mention male flowers with ‘reduced gynoecia’ in the description of his new section but while he gave the stylar length of ‘male’ flowers in the protologue of S. ogadense, he only gave the stylar dimensions of hermaphrodite flowers in the descriptions of S. dennekense and S. diplacanthum. The inflorescence stucture too appears complex in these species. Although Mattei described them as being forked and many-flowered in his protologue of S. arundo, they are often described as being few-flowered. Bitter (1923), when characterising his section Ischyracanthum, described the inflorescences as being “few (4–7–11)-flowered”, later citing those in S. dennekense and S. diplacanthum as being 4–7- and 4–5-flowered respectively. Moreover, they were also described as being supposely simple in the latter two species but ‘once-forked’ in S. ogadense (Bitter 1923). However, from the available herbarium material, condensed unopened buds and pedicels scars on the rachides indicate that both simple and complex branched cymes or racemes can occur on the same plant in these species. Simple inflorescences (2–6(–10) flowered) often occur terminally, while forked or multiply branched inflorescences tend to be lateral and up to around 16-flowered, though there can be up to 30+ with the inflorescence being up to 3.8 cm in diameter. It is possible that the reference to inflorescences being 1–2(–3) flowered by some authors (e.g. Friis, 2006 for S. arundo) may be due to including only fully open flowers. In addition, a basal pedicel often occurs, either at or very near (within 2 mm) the base of the vestigial or short peduncle. Specimens exhibit few mature berries with often only one berry apparently maturing on each infructescence. This is probably due to the andromonoecy characterising both S. dennekense and S. arundo. The powdery stellate indumentum of these species is also characteristic; it often sloughs off when the plants are handled, while the dense hair sheath clasping the stylar bases can usually be detached as a unit. Though small leaves characterise these species, their dimensions did not seem to be a consistent delimiting feature, and indeed seemed to be linked to habitat location. Bitter (1923) thought that S. arundo was possibly similar to or synonymous with one of the three species that he recognised, but considered Mattei’s protologue to be insufficient for a valid decision. In the absence of being able to examine type material he thought that the literal translation of Mattei’s berry description inferred that the enlarged fruiting calyx was accrescent and that this species could be more closely allied to S. dubium in the section Monodolichopus Bitter than to those in his new section. However, it is likely that Mattei’s description merely referred to the fruiting calyx lobes being persistent and adherent to the berry bases rather than accrescent and completely enclosing the berry. Bukenya & Hall (1988) thought that plants of S. arundo cultivated in Legon Botanical Garden, Ghana had probably been introduced from northern Kenya, and that it was not naturalised in Ghana. They also noted that this species is concentrated in the drier parts of East Tropical Africa and that it has also been recorded from the west coast of India. The seeds of Ethiopian specimens seem to be larger than those found on East African specimens whereas the flowers of Kenyan plants are reported to be larger than those in Somalia.
    Distribution
    Flora districts: K1 K4 K6 T2 Range: Somalia

    Images

    Distribution

    Native to:

    Ethiopia, Kenya, Somalia, Tanzania

    Synonyms

    Other Data

    Solanum arundo Mattei appears in other Kew resources:

    Date Reference Identified As Barcode Type Status
    Milne-Redhead, E. [7153], Kenya 28472.000
    Greenway, P.J. [12167], Tanzania K001157052
    Greenway, P.J. [12167], Kenya K001157053
    Greenway, P.J. [6751], Tanzania K001157054
    Gillett, J.B. [477], Somalia K001156077
    Gillett, J.B. [19174], Kenya K001157013
    Gillett, J.B. [15136], Kenya K001157037
    Gillett, J.B. [19248], Kenya K001157038
    Gillett, J.B. [21581], Kenya K001157039
    Bally, P.R.O. [2110], Somalia K001156079
    Bally, P.R.O. [8946], Kenya K001157015
    Bally, P.R.O. [12496], Kenya K001157047
    Bally, P.R.O. [5083], Kenya K001157048
    Bally, P.R.O. [4127], Kenya K001157051
    Eggeling, W.J. [6690], Tanzania K001157057
    Hepper, F.N. [7262], Kenya K001157042
    Sampson, H.C. [42], Kenya K001157026
    Gilbert, M.G. [5530], Kenya K001157011
    Burtt, B.D. [4276], Kenya K001157050
    Burtt, B.D. [5258], Kenya K001157058
    Bogdan, A. [3603], Kenya K001157009
    Hornby [2138], Tanzania K001157035
    Hemming, C.F. [1331], Kenya K001157028
    Stewart, J. [632], Kenya K001157045
    Faden, R.B. [71/394], Kenya K001157021
    Verdcourt, B. [2356], Kenya K001157012
    Napper, D.M. [748], Kenya K001157016
    Tweedie, E.M. [1848], Kenya K001157044
    Polhill, R.M. [2283], Kenya K001157055
    Kibuwa, S.P. [2476], Kenya K001157049
    Mwangangi, O.M. [1553], Kenya K001157030
    Newbould, J.G.B. [2951], Kenya K001157014
    Geilinger, W. [3742], Tanzania K001157033
    Leippert, H. [5010], Kenya K001157056
    Paulo, S. [488], Kenya K001157029
    Obunyali, C. [253], Kenya K001157024
    Gedye [7359], Kenya K001157041
    Milne-Redhead, E.W.B.H. [7153], Kenya K001157025
    Drummond, R.B. [1239], Kenya K001157046
    Pole Evans, I.B. [s.n.] K001157023
    s.coll [003/28/2000], Kenya K001157040
    Kariuki, J. [45177], Kenya K001157017
    Richards, M.A.E. [23641], Tanzania K001157027
    Richards, M.A.E. [24970], Tanzania K001157031
    Richards, M.A.E. [20351], Tanzania K001157034
    Richards, M.A.E. [28835], Tanzania K001157036
    Makin, M.S. [25], Kenya K001157010
    Nappes, D. [510], Kenya K001157018
    Mattrenge, S.G. [189], Kenya K001157019
    Vapier, E.R. [2651], Kenya K001157020
    Makin, J.G. [225], Kenya K001157022
    Marshall, P.H. [s.n.] K001157032
    Kibue, K. [103], Kenya K001157043

    Bibliography

    First published in 7: 188 (1908)

    Accepted by

    • PBI Solanum Project (2014-continuously updated). Solanaceae Source: a global taxonomic resource for the nightshade family http://www.solanaceaesource.org/.

    Literature

    Flora of Tropical East Africa

    • Fl. Somalia 3: 215 (2006).
    • K.S.T.L.: 580 (1994)
    • U.K.W.F., 2nd ed.: 243 (1994)
    • Bothalia 18, 1: 84 (1988)
    • Jaeger, Syst. stud. Solanum in Africa: 418 (1985, ined.)
    • Gentes Herb. 12: 263 (1984)
    • E.P.A.: 862 (1963)
    • Polhill, Solanum in E & NE Africa: 33 (ined., 1961)
    • Fl. Som 2: 335 (1932)
    • Chiovenda, Fl. Somalia: 241 (1929)
    • Boll. Reale Orto Bot. Palermo, 7: 188 (1908)

    Sources

    Flora of Tropical East Africa
    Flora of Tropical East Africa
    http://creativecommons.org/licenses/by-nc-sa/3.0

    Herbarium Catalogue Specimens
    'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
    Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2020. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2020. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0