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. Character P. ovatum P. englerianum Bark (colour on distal Younger stems: cream-brown Younger stems: pale grey stems) Older stems: brown Older stems: dark grey or dark grey-brown Indumentum (vegetative Dense sessile or short-stalked stellate and longer Dense sessile or short-stalked stellate trichomes parts) dendritic trichomes; not appearing matted (rarely few dendritic in addition); appearing matted Leaves Ovate, rotund or subrotund Narrowly to broadly elliptic, oblong-elliptic, (lamina shape) oblanceolate or rarely ovate Leaves (lamina apex) Acute, rounded, emarginate or truncate Acute, rounded or obtuse Leaves (lamina base) Cuneate, rounded, subcordate or truncate Attenuate, rarely cuneate Leaves (lamina ratio 1–1.5:1 1.7–3.1:1 length:width) Leaves (lamina size) 10–51 × 6–38 12–90 × 7–33 (mm) Bracteoles (shape) Broadly ovate Variable: ovate, narrowly obovate, oblanceolate, lanceolate or oblong-elliptic Bracteoles (size) (mm) 10–15 × 7–14 10.5–17.0 × 3.4–13.5 Corolla (upper lobes) Connate for 45–50% their length Connate for ca. 20–40% their length Corolla lobes (colour) Anterior lobe yellow, dotted burgundy at insertion of Anterior lobe yellow; other lobes pale yellow or trichomes, burgundy towards margins or burgundy orange, the latter usually fading to brownish orange on lateral margins only; other lobes burgundy in spent flowers Ovary (indumentum) Glabrous Scattered short-stalked glandular trichomes towards apex Distribution Namibia, Kunene Region from Khorixas to Bergsig Namibia, Kunene Region to the east of Khorixas; in the catchment area of the Huab River (Kaokoveld Otjozondjupa and Oshikoto Regions and eastwards Centre of Endemism) to northwestern Botswana