TABLE 1. Prominent morphological differences amongst Sesamothamnus leistneri, S. benguellensis, S. busseanus, S. guerichii, S. lugardii and S in A new species of Sesamothamnus (Pedaliaceae) from Namibia and Angola

TABLE 1. Prominent morphological differences amongst Sesamothamnus leistneri, S. benguellensis, S. busseanus, S. guerichii, S. lugardii and S. rivae.
CharacterS. leistneriS. benguellensisS. busseanusS. guerichiiS. lugardiiS. rivaeHabitSingle- or multi- stemmed tree, up to 8 m tallCompact low shrub to 2 m tall, rarely a shrub up to 3.5 m tallShrub or small multi- stemmed tree, 2–5 m tallShrub, 3–5 m tallShrub, 3–5 m tallShrub or small multistemmed tree, 2–6 m tallSucculence of main stemsHighHighLowMedium to highMediumLowLeaf laminaNarrowly ovate, narrowly obovate or elliptic, 40–70 × 15–40 mm, green, often shinyObovate to oblanceolate to broadly elliptic, 40–60 × 20–30 mm, green, dullObovate, 20–50 × 10–25 mm, pale green to yellowish green, dullObovate to oblanceolate, 20–30 × 5–8 mm, grey- green, dullOblong to obovate, 10–25 × 4–6 mm, grey, dullObovate (occasionally ovate), 20–80 × 30–60 mm, grey, dullMucilage hairsSparse; heads ca. quadrangularDense on abaxial side of leaf lamina; heads stellateSparse; heads ca. quadrangularDense on abaxial side of leaf lamina; heads stellateDense on abaxial side of leaf lamina; heads stellateSparse; heads ca. quadrangularFlowering periodDuring rainy season; plant with well- developed leavesProlonged and irregular; individual plant usually without leavesBefore onset of rainy season; plant still leaflessBefore onset of rainy season; plant still leaflessBefore onset of rainy season; plant still leaflessBefore onset of rainy season; plant still leaflessFlower basic colour of corolla limb (before fading)White or cream- coloured, tube may be purplish outsideWhite or cream- coloured, tube may be purplish outsideWhite or cream-coloured, tube may be purplish outsideYellowWhite or cream-coloured, tube may be purplish outsideWhite, cream-coloured or whitish brownCorolla tube (shape & size)Straight or only slightly curved, 95–150 mm long, 4–6 mm diam.Slightly curved, 50–80 mm long, 4–5 mm diam.Straight, 25–40 mm long, 3–5 mm diam. at base, widening to 7–11 mm diam. at throatCurved, sometimes S- shaped, 50–65 mm long, ca. 4 mm diam.Slightly curved, 80–100 mm long, 4–6 mm diam.Straight, 50–70 mm long, 2.5 mm diam. at base widening to 6 mm diam. at throatCorolla spurAbsent, posterior side of corolla tube base slightly gibbousPresent, 20–40 mm longPresent, 40–60 mm longAbsent but corolla tube base prominently gibbousPresent, 8–15 mm longPresent, 30–60 mm longFilamentsFree part ca. 1.5 mm longFree part ca. 2.5 mm longFree part ca. 1.5 mm longFree part 32–45 mm longFree part 4–5 mm longFree part 6–8 mm longPosition of anthersIn mouth of tubeIn mouth of tubeIn mouth of tubeExserted from tube to just before mouthIn mouth of tubeIn mouth of tubeDistributionFar southwestern Angola, southwards over the Kunene Rivere into northwestern Namibia to near SesfonteinSouthwestern Angola: coastal plain southwards crossing the Kunene River into northwestern Namibia as far south as the Rooidrom areaNortheastern Africa in Ethiopia, Somalia, Kenia, and TanzaniaNorthwestern Namibia: from the Rooidrom area southwards to OmatjetteSouthern Zimbabwe, eastern Botswana and northern South AfricaNortheastern Africa in Ethiopia, Somalia, Kenia, and Tanzania