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  1. Family: Solanaceae Juss.
    1. Genus: Solanum L.
      1. Solanum ruvu Voronts.

        This rare species has been collected only once, as part of a general survey in 2000. By the time it was identified as a new species by Kew botanist Maria Vorontsova in 2010, its native forest had already been destroyed. An expedition in 2010 tried to re-collect it but the plant was not found and is now most likely extinct.

    [KSP]

    Kew Species Profiles

    General Description
    A rare, African spiny aubergine, Solanum ruvu has been collected only once and is now likely to be extinct in the wild.

    This rare species has been collected only once, as part of a general survey in 2000. By the time it was identified as a new species by Kew botanist Maria Vorontsova in 2010, its native forest had already been destroyed. An expedition in 2010 tried to re-collect it but the plant was not found and is now most likely extinct.

    The story of Solanum ruvu highlights the way in which the destruction of Tanzania's coastal forests has impacted on biological diversity.

    Species Profile
    Geography and distribution

    Known from only a single collection in the Ruvu Forest in the Morogoro District of Tanzania.

    Coastal forests were once widespread along the eastern African seaboard but the majority have now disappeared leaving over 250 known remnant forest patches. These patches are typically isolated from each other by a mixture of farmland and thicket areas. Many have exceptional levels of local endemism, but are small, fragmented, surrounded by populated areas and are becoming rapidly degraded.

    The Ruvu Catchment Forest Reserve is poorly known and has not been explored in detail by botanists. It is situated in the eastern foothills of the Uluguru mountains and managed by the Forest Catchment project of the Morogoro Region.

    Solanum ruvu is known from a single collection made by the Frontier-Tanzania Coastal Forest Research Programme in 2000, most likely in the part of Ruvu Forest now known as the Chafungo forest fragment.

    Description

    Overview:  Solanum ruvu is a climbing herb or shrub with a dense covering of 4-6 mm long straight prickles.

    Leaves:  The leaves are 9-12 x 2.5-4.5 cm and are very thin, with almost no hairs.

    Flowers:  The unbranched inflorescences are 5-9 cm long, and bear 10-15 flowers. The inflorescence stalk is densely prickly. Only one or two flowers are open at any one time. The flowers are 1.2-1.8 cm wide, with long thin petals of 6-8 × 1.5-2 mm. The anthers are 5-6 mm long, and have openings at the tips.

    The only information we have about this species comes from a single herbarium collection (two herbarium specimens) and hence other details such as plant height, flower colour, fruits and seeds are unknown.

    Threats and conservation

    The Chafungo forest fragment is a highly fertile area with black cotton soil over limestone, and is difficult to reach by road. The Waluguru people were moved to the area during agricultural reforms in 1974 and population growth as well as clearance of the natural vegetation for agriculture has been on the increase ever since.

    The usual sequence of land cultivation starts with planting maize for the first two seasons following forest-clearance, later followed by matrix crops, including bananas, rice, sesame, tomato, and manihot (cassava). Sesame is also grown as a cash crop and provides the highest profit.

    Trees in the Chafungo forest fragment are said to have been cleared in 2003. Currently, the majority of the land there is used to grow rice and sesame. Approximately 3% of the area is occupied by limestone rocks and cannot be cultivated. Forest fragments with remnant natural vegetation can still be found on these limestone outcrops.

    The membranous leaves of Solanum ruvu , which almost completely lack indumentum (a covering of fine hairs or bristles), suggest that the species inhabited the dark and wet forest understorey, making it unlikely to survive clearance for agriculture.

    The Chafungo thicket vegetation, the nearby Kingira and Loholole fragments, and the surrounding area, were thoroughly searched during an expedition to Tanzania in March 2010. In none of the nearby forest fragments was a full tree canopy preserved, and S. ruvu was not refound. Local people did not recognise pictures of the plant and there is a real probability that this species may already have been driven to extinction. 

    Hunting for wild spiny aubergines in the Ruvu Forest

    An international botanical expedition, involving Maria Vorontsova (while working for the Natural History Museum, London and collaborating with Kew), Eric Tepe (University of Utah) and Frank Mbago (University of Dar es Salaam) searched for Solanum ruvu in March 2010.

    Searches were carried out in the Ruvu Forest and the Chafungo forest fragment at the exact latitude and longitude specified by the original collection. After two days of searching it was concluded that no intact coastal forest remained anywhere near the original collection area and that the forest fragments were not large enough to provide a forest canopy to support an understorey species such as S. ruvu .

    This species at Kew

    There are only two known herbarium specimens of this species: one held at Kew's behind-the-scenes Herbarium, and one at the Missouri Botanical Garden, USA.

    Distribution
    Tanzania
    Ecology
    Most likely wet coastal forest understorey, at about 100-300 metres above sea level.
    Conservation
    The preliminary assessment is Extinct (EX, IUCN, 2001). Efforts have been made to re-collect this species but failure to find it again and documented severe habitat destruction indicates that there is a high probability that it is now extinct.
    Hazards

    None known.

    [FTEA]

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

    Type
    Type: Tanzania, Morogoro District, Ruvu Forest Reserve, Mhoro UMBCP 113 (K!, holo.; MO!, iso.)
    General
    Prostrate or climbing subshrub, ± 1 m, armed; young stems almost glabrous, with minute simple hairs, the stellate trichomes present on the youngest parts only, porrect, translucent, sessile, rays 2–4, ± 0.05 mm, midpoints ± same length as rays; bristles straight, 4–6 mm long, ± 0.2 mm wide at base
    Leaves
    Leaf blades drying concolorous, brown-green, elliptic, 9–12 × 2.5–4.5 cm, 2.5–4 times longer than wide, base cuneate, usually equal, margin almost entire, rarely with shallow lobes, apex long-acuminate; almost glabrous, with minute simple hairs and stellate trichomes on the youngest parts only, trichomes on abaxial surface porrect, sessile, rays 2–4, ± 0.05 mm, midpoints ± same length as rays; primary veins 6–8 pairs; petiole 0.5–1.5 cm, 1/5–1/10 of the leaf length
    Inflorescences
    Inflorescences not branched, 5–9 cm long, with 10–15 flowers; peduncle 10–15 mm long; rachis 5–8 cm long; peduncle and rachis densely armed, the prickles like those on stems evenly covering the rachis; pedicels 0.7–1.2 cm long
    Flowers
    Flowers perfect, 5-merous
    Calyx
    Calyx 2.5–5 mm long, lobes deltate, 1.5–3.5 mm long, long-acuminate, often with numerous prickles
    Corolla
    Corolla 1.2–1.8 cm in diameter, colour not known, lobed for ± 4/5 of its length, lobes long-deltate, 6–8 × 1.5–2 mm
    Stamens
    Stamens equal; anthers 5–6 mm
    Ovary
    Ovary with minute glandular hairs; style ± 8 mm long
    Fruits
    Berries not known
    Ecology
    Moist coastal forest understorey; ± 200 m
    Note
    The unusually long filiform inflorescences with a dense covering of long straight prickles on the rachis have no parallels among the known Solanum species in Africa and Madagascar. The affinities of S. ruvu are most likely with S. zanzibarense, the only other scandent and sometimes subglabrous East African coastal forest species with subentire leaves, thin stems, and prickles that are sometimes straight. Failure to recollect this species suggests it may be extinct. A similarly dense covering of long and flexible prickles or bristles is found on two other East African species that are not directly related to S. ruvu: the savanna shrub S. setaceum in section Oliganthes and the montane forest shrub S. schumannianum.
    Distribution
    Range: Only known from the type Flora districts: T6

    Images

    Distribution

    Extinct in:

    Tanzania

    Other Data

    Solanum ruvu Voronts. appears in other Kew resources:

    Date Reference Identified As Barcode Type Status
    Mhoro, B. [113], Tanzania K000441557 holotype

    Bibliography

    First published in J. E. Afr. Nat. Hist. 99: 230 (2011)

    Accepted by

    • Humphreys, A.M., Govaerts, R., Ficinski, S.Z., Nic Lughadha, E. & Vorontsova, M.S. (2019). Global dataset shows geography and life form predict modern plant extinction and rediscovery Nature Ecology & Evolution 3: 1043-1047.
    • PBI Solanum Project (2014-continuously updated). Solanaceae Source: a global taxonomic resource for the nightshade family http://www.solanaceaesource.org/.

    Literature

    Kew Species Profiles

    • Edmonds, J.E., Vorontsova, M.S. & Knapp, S. 2012. Solanaceae. In: Flora of Tropical East Africa, ed. H. Beentje, Royal Botanic Gardens, Kew.
    • PBI Solanum Project (2010). Solanaceae Source.
    • Vorontsova, M.S. & Mbago, F.M. 2010. New Solanum species from Tanzanian coastal forests may already be extinct. Journal of East African Natural History.
    • Hall, S.M, Fanning, E. & Howell, K.M. (eds) (2004). Ruvu South Forest Reserve: a biodiversity survey. Frontier Tanzania Environmental Research Report 111. The Society for Environmental Exploration, the University of Dar es Salaam, Ulanga District Council, Kilombero Valley, Tanzania.

    Flora of Tropical East Africa

    • J. E. Afr. Nat. Hist. 99: 230 (2011).

    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

    Kew Species Profiles
    Kew Species Profiles
    http://creativecommons.org/licenses/by-nc-sa/3.0