TABLE 1. Prominent morphological differences between Petalidium ovatum and P in Reinstatement of the name Petalidium ovatum (Acanthaceae), with an amplified description of the species

TABLE 1. Prominent morphological differences between Petalidium ovatum and P. englerianum.
CharacterP. ovatumP. englerianumBark (colour on distalYounger stems: cream-brownYounger stems: pale greystems)Older stems: brownOlder stems: dark grey or dark grey-brownIndumentum (vegetativeDense sessile or short-stalked stellate and longerDense sessile or short-stalked stellate trichomesparts)dendritic trichomes; not appearing matted(rarely few dendritic in addition); appearing mattedLeavesOvate, rotund or subrotundNarrowly to broadly elliptic, oblong-elliptic,(lamina shape)oblanceolate or rarely ovateLeaves (lamina apex)Acute, rounded, emarginate or truncateAcute, rounded or obtuseLeaves (lamina base)Cuneate, rounded, subcordate or truncateAttenuate, rarely cuneateLeaves (lamina ratio1–1.5:11.7–3.1:1length:width)Leaves (lamina size)10–51 × 6–3812–90 × 7–33(mm)Bracteoles (shape)Broadly ovateVariable: ovate, narrowly obovate, oblanceolate,lanceolate or oblong-ellipticBracteoles (size) (mm)10–15 × 7–1410.5–17.0 × 3.4–13.5Corolla (upper lobes)Connate for 45–50% their lengthConnate for ca. 20–40% their lengthCorolla lobes (colour)Anterior lobe yellow, dotted burgundy at insertion ofAnterior lobe yellow; other lobes pale yellow ortrichomes, burgundy towards margins or burgundyorange, the latter usually fading to brownish orangeon lateral margins only; other lobes burgundyin spent flowersOvary (indumentum)GlabrousScattered short-stalked glandular trichomes towardsapexDistributionNamibia, Kunene Region from Khorixas to BergsigNamibia, Kunene Region to the east of Khorixas;in the catchment area of the Huab River (KaokoveldOtjozondjupa and Oshikoto Regions and eastwardsCentre of Endemism)to northwestern Botswana