Solanum phoxocarpum Voronts., 2010

Vorontsova, MS, Christenhusz, MJM, Kirika, P & Muthoka, P, 2010, Three new species of Solanum from Kenya: using herbarium specimens to document environmental change., Systematic Botany 35 (4), pp. 894-906 : 903-904

Solanum phoxocarpum Voronts. , sp. nov.

—TYPE: KENYA. Masai Province: Narok District, Lake Naivasha to the Enesambulai Valley, on the crest of the Western Rift Wall , 2 Nov 1969, P. G. Greenway & Kanuri 13869 (holotype: EA!; isotype: K000441270 !).

Species Solano aculeastri Dunal similis sed foliis caulium fertilium subintegris (nec lobatis), 6–8 cm tantum (nec 8–15 cm) longis et 2.5plo (nec 1.5–2plo) longioribus quam latioribus, floribus lilaciniis (nec plerumque albidiis), baccis conicis (nec plerumque globosis neque ellipsoideis) et duplo (nec minus quam duplo) longioribus quam latioribus differt.

Erect shrub to small tree, 1–3(–6) m, armed, much branched at base; young stems long and slender, densely stellatepubescent; trichomes multangulate, white-translucent, irregular and densely matted, sessile, the rays 11–16, 0.1–0.2 mm, the midpoints same length as the rays or up to 0.8 mm long; prickles 6–15 mm long, 2–7 mm wide at the widest point, straight or curved, rounded to flattened, orange-brown; main branches up to 20 cm in diam at base, glabrous to glabrescent in patches; bark smooth red-brown to almost white. Sympodial units appearing plurifoliate, not geminate. Leaves simple, the blades on fertile branches 6–8 × 2.5–4 cm (larger on vegetative branches), ca. 2.5 times longer than wide, elliptic, chartaceous, drying strongly discolorous, reddish-green above, white-grey underneath, densely stellate-pubescent abaxially; trichomes porrect to multangulate, white-translucent, a mixture of sessile and stalked, the stalks ca. 0.1(–0.2) mm, the rays 11–16, 0.15–0.3 mm, the midpoints same length as the rays or up to 0.8 mm long, adaxially almost glabrous; the blades unarmed, sometimes with 1–2 straight prickles up to 5 mm long; midvein raised abaxially, sunk adaxially, the primary veins (4–)5–6 pairs, spreading at 30–45° to the midvein, the tertiary venation visible on both sides of the leaf; base cuneate, usually equal; margin subentire to weekly lobed, the lobes 1–2(–3) on each side, up to 0.5(–1.5) cm long, extending up to 1/3 of the distance to the midvein (larger on vegetativebranches), broadly rounded; apexacute; petiole 0.5– 0.9 cm, ca. 1/6orlessof theleaflength, unarmed.Inflorescences apparently terminal or lateral, 3–5.5 cm long, not branched, 1–7-flowered, with 1 flower open at a time, densely stellatepubescent, the trichomes often with elongated midpoints, unarmed; peduncle 0–0.6 cm long; rachis 0–0.3 cm long; pedicels 1.8–3 cm on long-styled flowers, 0.8–1.2 cm on shortstyled flowers, slender, articulated less than 0.5 mm from base, stellate-pubescent in patches, the trichomes often with elongated midpoints, sometimes with 1–2 prickles on long-styled flower pedicels; pedicel scars broad dark stumps, spaced 1– 2 mm apart. Buds ovoid to ellipsoid. Plants andromonoecious, with 1(–3) long-styled flowers at the base of the inflorescence, the flowers 5(–6)-merous. Calyx ca. 15 mm long on long-styled flowers, ca. 7 mm long on short-styled flowers, long-cupular, divided for ca. 2/3 of its length on long-styled flowers, for ca. 1/2 of its length on short-styled flowers, the lobes 7–10 × 2–3 mm in long-styled flowers, ca. 4 × 2 mm in short-styled flowers, mostly equal, sometimes with one lobe much longer than the others, long-deltoid, apically acute to apiculate, with no venation visible or a faint raised midvein, densely stellate-pubescent, unarmed or with up to 15 prickles to 5 mm long in long-styled flowers, unarmed in short-styled flowers. Corolla ca. 3 cm diam in long-styled flowers, ca. 1.7 cm diam in short-styled flowers, blue-mauve, drying orange-brown, slightly reflexed, stellate, lobed for 1/2–2/3 of its length, the lobes 10–15 × 4–5 mm in long-styled flowers, 6 × 3–4 mm in short-styled flowers, deltoid, with a dark midvein, densely stellate-pubescent abaxially, the trichomes porrect, irregular, orange-translucent, sessile, the rays 8–15, 0.1– 0.3 mm, undulate, the midpoints shorter than the rays, lengthening towards corolla lobe apices, mostly glabrous adaxially, the trichomes variously reduced and irregular. Stamens with the filament tube ca. 2 mm; free portion of the filaments ca. 1.2 mm; anthers 3.5–4 mm, free, equal, tapering, poricidal at the tips, the pores lengthening into longitudinal slits with age, the anther surface drying orange to red-brown. Ovary ca. 2.5 mm in diam, broad-ovoid, densely stellate-pubescent in the upper 1/5; style ca. 7 mm long on long-styled flowers, thick, dark brown, straight or almost straight, stellate-pubescent in the lower 1/3, exserted 3–4 mm beyond the anthers; stigma clavate, papillose. Fruit a conical berry, 1(–3) per infructescence, 2.8–3.7 × 1.8–2.2 cm, ca. two times longer than wide, apically pointed, retaining the same elongated pointed shape throughout development, the pericarp thin, usually smooth, sometimes warty, shiny, glabrous, with afewstellatetrichomes near the apex on immature fruit, evenly green when young, yellow at maturity, drying almost black when young and drying orange-brown at maturity; fruiting pedicels 2.5–4 cm long, 1.2–1.8 mm wide at base, woody, held erect becoming pendulous as the pedicel dries, usually with 2–10 prickles up to 7 mm long in the apical part; calyx sometimes accrescent to 2.5 cm long, covering 1/6–1/4(–1/2) of the mature fruit, not reflexed, with 0–10 prickles ca. 5 mm long. Seeds ca. 30 perberry, 4–4.5 × 3–4 × ca. 0.3 mm, flattened-reniform, almost round, often somewhat irregular in outline, brown to almost black, the surface smooth or with raised outlines of cells or small pits. Figures 3 , 5 E-H. Table 4 .

Distribution and Habitat— Endemic to the East African Rift Valley, including the Rift Valley Province, Central Province, and Masai Province in Kenya and Northern Province in Tanzania. Damp forest understorey or secondary scrub at 2,100–3,000 m altitude. Figures 1B , 5E .

Common Names— Masai vernacular names are “Osigawai” and “Sigawet.”

Uses— The plants are used for hedges and the fruit is eaten. Roots are boiled in water and the liquid is then mixed with broth and taken as a remedy for gonorrhoea. The ripe dry fruits are roasted and then ground to powder and mixed with butter to give to babies.

Etymology— Solanum phoxocarpum means “pointy-fruited solanum”, derived from the Greek “phoxos” meaning pointed or peaked and “karpos” meaning fruit.

Specimens Examined— KENYA.Central Province:Mount Kenya,10 Sep 1970, Archer 639 (EA); Limoru, 30 Aug 1939, Bally 7438 (EA, K); Aberdare National Park, 23 Jun 1978, Campbell s. n. (EA); Mount Kenya, 22 Oct 1981, Cheseny 61 (EA); Aberdare National Park, 1 Jan 1922, Fries 632 (EA); Aberdare National Park, 7 Apr 1975, Hepper & Field 4910 (K); Mount Kenya, 15 Sep 1970, Kokwaro & Mathenge 2340 (EA); Chogoria, 26 Oct 1987, Luke 681 (EA); Aberdare National Park, 4 km from Muringa to bridge towards the mooreland, 13 Mar 2007, Mbale et al. NMK844 (K); Limoru, 4 Jul 1909, Scheffler 306 (K); Mount Kenya, Naro Moru Track, Verdcourt, B. 3725 (EA, K); Mount Kenya, mountain lodge near Nyeri, 6 Dec 1974, Williams 63 (EA, K).Masai Province:Oldonyo Orok, 6 Dec 1944, Bally 4141 (EA, K); Molo, 22 Feb 1951, Gillett 43,551 (EA); Olokurto, Mau Area, 13 May 1961, Glover et al. 935 (EA, K). Rift Valley Province: Timbora, 25 Jul 1938, Evans & Erens 1468 (K); Kinangop, 11 Jul 1965, Gillett 16,766 (EA, K); Mau Narok, 5 Jul 1976, Gitonga 61 (EA); near Timboroa, 2 km Sof equator, 27 Dec 1986, Robertson 4404 (K); Timboroa, by Londiani turning, Apr 1972, Tweedie 4315 (K).

TANZANIA. Northern Province: Ngorongoro Crater, 2,100 m, 16 Aug 1973, Frame 229 (EA, K); Ngorongoro Crater, 21 Jul 1968, Gilbert 2994 (EA); Ngorongoro Crater, 28 Jan 1965, Herlocker 12 (EA); Longido Mt, 2530 m, 8 Jul 1976, Paterson 146 (EA); Embagai, 5 Feb 1932, Saint Claire Thompson 1255 (K). Tanga Province: Gologolo, 9 Jun 1958, Mgaza 172 (EA).

Notes— Solanum phoxocarpum is a high-altitude species with unusual long and pointed fruit, subentire leaves, and mauve flowers. It is closely related to the widespread S. aculeastrum but lacks its strongly lobed leaves on fertile branches, the corolla is mauve, and less dissected. Both species are found in the habitat mosaics characteristic of the Kenyan Rift Valley and are found growing together in woodland above 2,100 m. Some populations of S. aculeastrum in Uganda and the Democratic Republic of the Congo have long pointed fruit like that of S. phoxocarpum as well as leaves that are less lobed than average, but these leaves are not as long and thin as those of S. phoxocarpum and these plants have denser and longer indumentum. Morphology of S. aculeastrum is reminiscent of typical juvenile Solanum morphology with more leaf lobing and abundant prickles ( Roe 1966), while the morphology of S. phoxocarpum is more similar to the typical mature Solanum morphology with more entire leaves and fewer prickles.

Solanum phoxocarpum is the species designated as Solanum aculeastrum Dunal var. 1 by Polhill (in mss.), Solanum aculeastrum Dunal subsp. 1 by Jaeger (1985), and Solanum sp. K sensu Agnew and Agnew (1994). Udo Dammer has also recognised the distinctness of these plants and annotated the sheet Scheffler 306 (K) as “ Solanum sepiaceum Dammer var. fructile verrucans spec. nov.” in Dammer’shandwriting, with aprinted label “Brit. Uganda. Station Lamuru. Buschiges Hochland. b. c. 3,000 m”. This name does not seem to have been published and the specimen is not cited in the protologue of S. sepiaceum Dammer ( Dammer 1905) . “Station Lamuru” most likely refers to Limuru in Kenya, Central Province ( Polhill 1988).

Figures

FIG.3. Solanum phoxocarpum Voronts. sp. nov. A. Habit in flower. B. Flower. C. Flower and calyx. D. Underside of the leaf. E. Underside of leaf showing stellate trichomes. F. Stellate trichome. G. Habit in fruit. H. Fruit, longitudinal cross section. I. Seed. A, B, C, H drawn from field photographs of Vorontsova et al. 29. D, E, F, G drawn from herbarium specimen Verdcourt 3725. I drawn from herbarium specimen Frame 229. Scale bar: A = 2 cm; B, C, D, H = 3 cm; E, I = 2.5 mm; F = 0.5 mm; G = 2.5 cm. Drawn by Lucy T. Smith.

FIG. 5. Three new species and their habitats in Kenya. A – D. Solanum polhillii Voronts. sp. nov. on Mount Suswa. E – H. Solanum phoxocarpum Voronts. sp. nov. in the Aberdare National Park. I – L. Solanum malindiense sp. nov. at the Mayungu beach. Photographs A – H by Maarten Christenhusz. Photographs I – L by Maria Vorontsova.

FIG.1. Distribution of the three new species in Kenya and Tanzania. A. Solanum polhillii Voronts. sp. nov. B. Solanum phoxocarpum Voronts. sp. nov. C. Solanum malindiense Voronts. sp. nov. Collecting localities not visited are marked as black triangles. Collecting localities visited where the plants were not found are marked as red circles. Collecting localities visited where the plants were found are marked as green squares. Drawn by Paweł Ficinski.