Solanum polhillii 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 : 902-903

Solanum polhillii Voronts. , sp. nov.

—TYPE: KENYA. Masai Province: Narok District, Ewaso Ngiro - Loliondo Road where it crosses the Masan River , 13 Dec 1963, B. Verdcourt 3838 (holotype: EA!; isotypes: K000441234 !, K000441243 !).

Ab aliis speciebus africanis Solani gemmis inflatis et sepalis carinatis differt. A Solano richardii Lam. foliis 2–6 cm tantum (nec 7–22 cm) longis, antheris 4.5–8 mm tantum (nec 8.5– 11.5 mm) longis differt.

Erect woody shrub, 1–2 m, armed, moderately branched; young stems stout, straight, erect, sparsely to densely stellatepubescent; trichomes porrect, translucent, stalked, the stalks up to 0.2 mm, the rays 7–9, 0.1–0.2 mm, the midpoints same length as the rays or shorter, often reduced to globular unicellular glands; prickles 2–3(–6) mm long, 0.5–1.5 mm wide at widest point, straight to slightly curved, perpendicular to the stem or somewhat reflexed, orange-brown to yellow; main branches 1–2 cm in diam at base, glabrescent; bark smooth, grey or brown. Sympodial units difoliate, not geminate. Leaves simple, the blades 2–6 × 1–4 cm, 1.5– 2 times longer than wide, ovate, chartaceous, drying discolorous, yellow-green, densely stellate-pubescent on both sides; trichomes porrect, translucent, stalked, the stalks up to 0.2 mm, the rays ca. 8, 0.1–0.3 mm, the midpoints same length as the rays or shorter, adaxially with reduced rays pointed upwards; the blades unarmed; midvein raised abaxially, flat or sunk adaxially, the primary veins 3–4 pairs, spreading at 30–60° to the midvein, the tertiary venation usually not visible to the naked eye; base cordate, rarely rounded or cuneate, often oblique; margin entire to weakly lobed, the lobes, if present, 1–2 on each side, up to 3 mm long, extending up to 1/4 of the distance to the midvein, broadly rounded; apex rounded or obtuse; petiole 0.3–2.5 cm, 1/3 of the leaf length to as long as the leaf, unusually variable, rarely with 1–2 prickles. Inflorescences usually terminal, sometimes apparently lateral, 2–4.5 cm long, not branched, 1–4-flowered, with 1(–2) flowers open at a time, stellate-pubescent like the young stem, unarmed or with 1–3 small prickles; peduncle 0–5 mm long; rachis 0–2 cm long; pedicels 10–15 mm long, slender at base, inflated towards the sepals, articulated less than 0.5 mm from base, unarmed or with a few prickles; pedicel scars inconspicuous stumps. Buds broad-ovoid or almost globose, conspicuously inflated in living material. Plants andromonoecious, with 1(–2) long-styled flowers at the base of the inflorescence, the flowers 5-merous. Calyx 8–16 mm long, obconical, divided for 3/4–5/6 of its length, the lobes 4.5–12 mm long, 1–1.5 mm wide at base, equal, long-deltoid to thin-oblong, apically long-acuminate, with pronounced keels visible on fresh material, with no venation visible or a raised midvein, densely stellate-pubescent like the young stem, unarmed or more rarely with up to 10 filiform prickles to 1.5 mm long. Corolla 2–4.2 cm in diam, deep purple, drying orange-brown or somewhat pink, stellate, tearing unevenly at anthesis, opening fully or slightly reflexed, lobed for 2/3–3/4 of its length, the lobes 7–15 × 4.5–10 mm, broad-deltoid to ovate, apically cuspidate, with a clearly visible network of brown veins, densely stellate-pubescent abaxially, the trichomes porrect, orange-translucent, subsessile, the stalks up to 0.1 mm, the rays ca. 8, 0.1–0.25 mm, the midpoints same length as the rays or shorter, slightly longer than rays towards corolla lobe apices, mostly glabrous adaxially, the trichomes variously reduced and irregular. Stamens with the filament tube 2– 2.5 mm; free portion of the filaments 1.7–2 mm; anthers 4.5– 8 mm long, 1–2 mm wide, free, equal, tapering, poricidal at the tips, the pores lengthening into longitudinal slits with age, the anther surface drying papillose, yellow-orange to dark red-brown, often sparsely stellate-pubescent on the dorsal surface. Ovary ca. 2.5 mm diam ovoid-globose, upper part of the ovary usually visible in fully open long-styled flowers, densely stellate-pubescent over its entire surface; style 0.8– 1.2 cm long on long-styled flowers, slender, curved, exserted 3–5 mm beyond the anthers, stellate-pubescent in the lower 1/4; stigma clavate, papillose. Fruit a globose berry, 1(–2) per infructescence, 13–20 mm in diam, ovoid or spherical during development, becoming spherical at maturity, the pericarp thin, smooth, shiny, the whole surface visibly stellate-pubescent during development, becoming glabrous at maturity, marbled green and white when young, yellow to orange at maturity, dryingyellowtoorange-brown; fruitingpedicels0.8– 4 cm long, 0.6–1 mm wide at base, becoming woody, pendulous, unarmed or with up to 15 small prickles, the apical 5–10 mm inflated; calyx slightly accrescent, covering 1/3 to all of the mature fruit, usually unarmed, rarely with up to 10 prickles.Seedsca.30–100 perberry, 2.8–3×2–2.5×ca.0.3 mm, flattened-reniform, often somewhat irregular in outline, pale yellow to orange-brown, the surface smooth or with raised outlines of cells or small pits. Figures 2 , 5 A-D. Table 3 .

Distribution and Habitat— Kenya and Tanzania. Savanna, rocky hillsides, bushland and scrub, on granite, volcanic rocks or red sandy soil, sometimes locally common, 1,800–2,200 m elevation. Figures 1A , 5A .

Common Names— The Masai names include “Endulelei,” “Oliasuria,” and “Entenelua-Narok.”

Uses— Decoction of the roots used as cure for anthrax by rubbing into the abscesses; the Masai attribute strong medicinal powers to the “Endulelei”.

Etymology— The epithet honours Roger Polhill’s contribution to East African botanical taxonomy as a whole and Solanum in particular.

Specimens Examined— KENYA. Central Province: Lukenya rocks by Nairobi-Mombasa Road., 2 Jun 1980, Gilbert 5961 (EA, K); Ilpartimaro, 26 Nov 1977, Kuchar & Msafiri 8013 (EA). Masai Province: Ngong Hills, Oct 1937, Anonymous 158 (EA); Ngong Hills, 12 May 1960, Archer 76 (EA); Suswa lava flow, near Narok Road, Jun 1960, Archer 117 (EA, K); 22 miles on Kajiado - Namanga Road., 29 Nov 1960, Archer 208 (EA, K); Namanga Hill river valley, 8 Mar 1964, Archer 434 (EA, K); Ngong Escarpment, Jun 1940, Bally 2333 (EA, K); Suswa, 31 Oct 1943, Bally 2922 (EA); Ngong Escarpment, 21 Dec 1947, Bally 4745 (EA, K); Suswa crater near rim, 23 Mar 1963, Bally 12657 (K); Western slopes of Ngong Hills, 12 Dec 1947, Bogdan 1474 (K); near Kenya Marble co, quarry SW of Kajiado, 27 Nov 1977, Gilbert 4933 (EA, K); Makueni: Tsavo West National Park, 13 Aug 1965, Gillett 16842 (EA); Suswa volcanic cave area, 6 Apr 1963, Glover 3605 (EA, K); Mount Suswa, 4 Aug 1963, Glover 3854 (EA); Mount Suswa, 5 Aug 1964, Glover 4570 (EA); Mount Suswa, 14 Feb 1964, Glover & Oledonet 4133 (EA); Mount Suswa, 13 Mar 1964, Glover & Oledonet 4446 (EA); Mount Suswa, 15 Mar 1964, Glover & Oledonet 4500 (EA); Lower NW slopes of Suswa near the Narok-Kijabe road, 20 Apr 1962, Glover & Samuel 2736 (EA, K); Olenyamu, about 38 miles from Magadi on the road to Nairobi, 30 Jun 1962, Glover & Samuel 2908 (EA, K); Loita, 25 Dec 1984, Hohl 348 (EA); Mount Suswa, 1 Jun 1969, Ivens 2463 (EA); Masai Mara Game Reserve, 24 Sep 1978, Kuchar 9911 (EA); Ilgeri, 26 Feb 1979, Kuchar 10669 (EA); Ewaso Nyiro, 1875, 11 Jan 1981, Kuchar 13858 (EA); Ewaso Nyiro, 11 Jan 1981, Kuchar 13917 (EA); Narok, 1850, 10 Aug 1977, Kuchar & Msafiri 6901 (EA); Ollaro Camp, 11 Feb 2001, Luke & Luke 7317 (EA, K); Ngong escarpment, 9 Jun 1931, Napier, E.R. 1339 (EA, K); Ngong Hills, Dec 1934, Napier 3594 (EA); Rift Valley W of Ngong Hills., 13 Dec 1934, Napier 6723 (K); Ngong Escarpment, Dec 1934, Napier 6724 (K); Mount Suswa, 15 Jul 1985, Parsons & Lambert 3 (EA); 37 miles from Nairobi on Magadi road, 12 Apr 1960, Polhill et al. 2672 (EA, K). Rift Valley Province: Kedong Valley, 1 May 1960, Archer s. n. (EA); Ol Longonot, 10 May 1960, Kerfoot 1860 (EA, K); Ol Longonot Estate, 29 Dec 1961, Kerfoot 3393 (EA, K); Ol Longonot Estate, 28 Jan 1962, Kerfoot 3597 (EA); Ol Longonot Estate, 31 Jul 1962, Kerfoot 4001 (EA, K); Uaso Narok River on Kisima Farm, 40 km Nof Rumuruti, 13 Nov 1977, Stannard & Carter 333 (EA, K).

TANZANIA. Lake Province: Moru Kopjes, Serengeti Plains, 31 Dec 1971, Greenway & Turner 14,952 (K); Serengeti Central Plains, 2 miles W of the Eastern Boundary, 30 May 1962, Greenway & Watson 10677 (EA, K); Seronera, Seronera Rest Camp, 25 Apr 1958, Paulo 377 (EA, K). Northern Province: Longido Mt., 1676, 24 May 1967, Carmichael 1404 (EA); Soitayai, 29 Nov 1956, Greenway 9086 (EA, K); Serengeti National Park, 29 Nov 1969, Herlocker 610 (EA); Oldiang’aranger, E. Serengeti, 19 Nov 1962, Newbould 6267 (EA, K); Oldiang’arangar, E. Serengeti, Nov 1962, Oteke 228 (EA, K); Serengeti National Park, Dec 1963, Turner 12900 (EA).

Notes— Solanum polhillii is an attractive erect pubescent shrub with noticeable mauve flowers, broad pubescent leaves and apically inflated pedicels. The wide stamens and broad corollas are similar to those of S. richardii , while the vegetative morphology is reminiscent of S. taitense Vatke and S. setaceum Dammer. Morphology varies with environmental conditions such as aridity, nutrient availability, and herbivory, including leaf size, petiole length and prickliness. Particularly remarkable is the variation in flower size, with the corolla 2–4.2 cm wide and the anthers 4.5–8 mm long, smaller than the more southern S. richardii but larger than most other species in the region.

Solanum polhillii is the species designated as Solanum sp. nov. 2 by Polhill (in mss.) and Solanum sp. Gsensu Agnew and Agnew (1994) and Beentje (1994). It does not fit comfortably into any sections accepted by Bitter (1913, 1917, 1921, 1923) or Jaeger (1985), many of which are not monophyletic ( Levin et al. 2006; S. Stern, unpubl. data). Polhill (in mss.) placed it in Bitter’s section Ischyracanthum , an unlikely placement as S. polhillii lacks overall similarity to its members and also lacks the curved stem prickles that define that section. In spite of vegetative similarity to members of Bitter’s section Oliganthes , its fruits are yellow rather than orange to red and its flowers are too large to fit comfortably into that group. Perhaps the position of S. polhillii will become clearer with further molecular phylogenetic studies.

Figures

FIG.2. Solanum polhillii Voronts. sp. nov. A. Habit in sheltered habitat. B. Underside of leaf showing stellate trichomes. C. Stellate trichome. D. Habit in exposed habitat. E. Bud. F. Flower. G. Immature fruit. H. Mature fruit. I. Seed. Drawn from herbarium specimens. A, B, C, E, F from Verdcourt 3838. D drawn from Greenway 9086. G and H from Verdcourt et al.2672. I from Greenway 10671. Scale bar: A, D = 2.5 cm; B, I = 2.5 mm; C = 0.5 mm; E, G, H = 1 cm; F = 2 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.