Solanum tettense
Not known
Mid-elevation areas of sub-Saharan Africa from Ethiopia to Transvaal; growing in Acacia (Vachellia)-Commiphora bushland, Brachystegia woodland, savanna, open areas and on rocky slopes, common on termite mounds; (450-) 650 – 1600 m elevation.
Solanum tettense is a member of the Old World clade of the spiny solanums (Leptostemonum; Levin et al. 2006); within that group it belongs to the Giganteum Clade along with Solanum giganteum, Solanum goetzei and other similar species (Vorontsova et al. 2013).
Gonçalves, A. E. 2005. Solanaceae. In Flora Zambesiaca vol. 8(4), ed. G. V. Pope, R. M. Polhill and E. S. Martins, 1-124. Kew: Royal Botanic Gardens, Kew.
Levin, R. A., N. R. Myers, and L. Bohs. 2006. Phylogenetic relationships among the “spiny solanums” (Solanum subgenus Leptostemonum, Solanaceae). Amer. J. Bot. 93: 157-169.
Vorontsova, M. S., S. Stern, L. Bohs, and S. Knapp. 2013. African spiny Solanum (subgenus Leptostemonum, Solanaceae): a thorny phylogenetic tangle. Bot. J. Linn. Soc. 173: 176-193. doi:10.1111/boj.12053
Local Names. Somalia: Amba Orbey (O’Brien 185). Kenya: Karithi or Karidi (Bally & Smith B14457), Mukondu (Kamba language, Van Someren 159/275), Mutongatongu (Kamba language, Mwangani & Napper 1345), Mutongatonga (Kitui, Gardner 3692), Muthugi (Graham 2256), Loptwo Kaner (Pokot language, Meyerhoff 69M), Loputwa (Pokot, Timberlake 504), Chuchwen (PokotMeyerhoff 136M), Dongadongo (Kikamba language, Bally 7785). Uganda: Ekujon (Hudson 191). Tanzania: Mupwa (Irangi language, Burtt 1443), Ndura (Kihehe language, Greenway & Kanuri 13949).
Uses. Of limited medicinal use in Kenya and Botswana.
Solanum tettense is a common shrub of dry areas recognisable by its strongly discolorous regular ovate leaves and deltate stem prickles. Solanum tettense as circumscribed here follows Gonçalves (2005) and includes the more southern S. kwebense as well as S. renschii. Variation is fully continuous in a north to south cline, with the southern populations (S. kwebense) with fewer flowers and white corollas (versus mauve corollas in the northern populations of S. tettense s. s.). Southern populations also have greater trichome diversity: simple trichomes with brown glands at the apices occur quite commonly and are especially prominent on species with little cover of stellate trichomes. Stellate trichomes usually do not bear glands but stellate trichomes with glandular midpoints are sometimes seen, often with multicellular segmented midpoints, and occasionally with gland tips also present on lateral rays. Glandular apices are particularly abundant on the pedicels, petioles, and leaf margins, although they are also present on the young stems and leaf blades. The majority of S. tettense populations seem to consist of erect shrubs although they can be scandent or scrambling up surrounding vegetation. The overall appearance of S. tettense is fairly uniform across most of its distribution range, with the exception of its eastern boundary with S. wittei, and a range of aberrant individuals from southern populations that are pricklier and/or smaller-leaved and/or more glabrous.
Our circumscription of S. tettense does not include collections from the inland area surrounding the lakes in Rwanda, Democratic Republic of the Congo, southern Uganda, or adjacent northwestern Tanzania, which have been placed in S. wittei. Solanum tettense differs from S. wittei by its strongly discolorous leaves (versus concolorous to weakly discolorous leaves in S. wittei), usually acute and finely rounded leaf tips (versus acuminate leaf tips in S. wittei), anthers 4-6 mm long (versus 3.5-4 mm long in S. wittei), stem and leaf stellate trichome midpoints same length as the rays (versus the midpoints elongated to 0.4-1(2) mm in S. wittei), and stellate trichomes on the leaves with 4-20 rays (versus only 0-12 rays in S. wittei). The inflorescences of S. wittei are longer with the flowers more widely spaced, and have fewer flowers than those of S. tettense, although due the variability encompassed in S. tettense these differences are not clear when measurement ranges for the two species are compared. The boundary between S. wittei and S. tettense in somewhat unclear where the two species may be sympatric in western Uganda and Tanzania. Three Tanzanian collections with a combination of discolorous leaves, dense inflorescences, and elongated midpoints (Tanner 1061, Tanner 4928, and Procter 847) have been provisionally placed in S. wittei. Collections from western Uganda are placed in S. tettense with the exception of Thomas 3988 with long midpoints and short anthers which has been placed in S. wittei.
Solanum giganteum is largely sympatric with S. tettense which also has strongly discolorous leaves and deltate prickles; S. giganteum can be distinguished from S. tettense by its elliptic leaves 12-40 cm long (versus ovate leaves 4-10(16)cm long in S. tettense), 30-150 flowers per inflorescence (versus 10-30 flowers per inflorescence in S. tettense), and anthers 2.5-3 mm long (versus anthers 4-6 mm long in S. wittei). Solanum tettense generally occurs in drier areas at lower elevations. The southern populations of S. tettense are sometimes confused with S. catombelense, and can be distinguished from the latter by their entire leaves (versus shallowly lobed to almost entire leaves in S. catombelense), anthers 5-5.5 mm long (versus anthers 2.5-3.5 mm long S. catombelense), and stellate trichomes on the stems with 10-25 lateral rays (versus 6-8 lateral rays in S. catombelense).
We have chosen the duplicate of Peters s. n. at EA as the lectotype of S. tettense because it has a label “Ex Museo Botanico Berolinensi” suggesting it originated in Berlin and is thus likely to have been seen in Berlin by Klotzsch, and also due to its location in Africa. The choice of lectotype for S. renschii follows the unpublished choice made by R. Lester. Lugard 50 (K000414100) is chosen as the lectotype of S. kwebense because it contains more complete flowering material than the second collection cited in the protologue, Lugard 62 (Kwebe Hills, 20 Dec 1897, K000414099). We have chosen Z000027800 as the lectotype of S. luederitzii due to its being more complete material compared to the second duplicate at Z where Schinz carried out his work, Z000027801. We have lectotypified S. upingtoniae with the Z duplicate of Schinz 868, as that is where he worked, although the material at K perhaps formed part of the set of material he originally examined. The lectotype of S. kibweziense is the only known duplicate of the type collection that was destroyed in Berlin. The duplicate K000413981 is selected as the lectotype of S. koniortodes due to its most complete material. The sheet of the type collection of S. baidoense at FT has an annotation as “sp. nov.” in Chiovenda’s hand; we have selected this sheet as the lectotype, even though no other sheets have been seen; the colonial Italian herbaria were dispersed to several institutions and duplicates could be extant. The type collections of S. chiovendae, S. grewioides, and S. munitum var. javellense at FT are each mounted on two sheets, with one duplicate illustrated in the protologues and the other duplicate with Lanza’s annotation label attached. The duplicates with more ample material chosen for protologue illustrations have been selected as lectotypes: FT003008 for S. chiovendae, FT003010 for S. grewioides and FT003006 for S. munitum var. javellense.