Hibiscus krichauffianus

McLay, Todd G. B., Barker, Robyn M. & Albrecht, David E., 2023, Morphological and environmental variation within Hibiscus krichauffianus (Malvaceae), and the recognition of two new species, H. verecundus and H. calcareus, Australian Systematic Botany 36 (6), pp. 457-477 : 465-466

Key to Hibiscus krichauffianus and related species

1. Epicalyx lobes fused at the base for more than 4 mm or if fused for less than 4 mm then free part never narrowly linear nor with a length to width (l:w) ratio higher than 4:1...... H. sturtii complex Epicalyx free or fused at base for less than 4 mm, free part narrowly linear with a l:w ratio higher than 4:1........................................... ..................................................... 2 H. krichauffianus and allies

2. Young branchlet indumentum yellowish-brown; adaxial leaf surface green to dark green; stipules 0.1–0.17 mm wide; epicalyx lobes free or fused at base for up to 0.5 mm, free part straight in flower and fruit; seeds less than 2.5 mm long, with a patchy covering of appressed hairs....................................................... H. verecundus Young branchlet indumentum white, silvery-white, grey or yellowish-white; adaxial leaf surface whitish, greyish, silvery or ferruginous; stipules 0.16–0.5 mm wide; epicalyx lobes free or fused at base for up to 3.5(–4) mm, free part straight in flower and becoming recurved in fruit; seeds 2–3 mm long but if less than 2.5 mm long then with a sparse to moderate covering of non-appressed hairs............................................................................. 3

3. Branchlet indumentum becoming ferruginous on older branchlets; adaxial leaf surface silvery–ferruginous; epicalyx lobes free or fused at base for up to 1 mm; petals 39–42 mm long, apparently purple; seeds with a patchy covering of appressed hairs .............. ............................................... H. sp. Belele (D. W.Goodall 3417) Branchlet indumentum not becoming ferruginous with age; adaxial leaf surfaces not ferruginous; epicalyx lobes free or fused at base for up to 3.5(−4) mm; petals 17–44 mm long, pale pink or mauve; seeds with covering of appressed or non-appressed hairs............ 4

4. Erect or ascending shrub or subshrub to ~ 1 m high, growing in deep sands; leaf lamina 10–55 mm long and 5–35 mm wide, flat to weakly concave or weakly folded in transverse section, the sinus between marginal dentations never reaching halfway to the midvein, pedicel abscission point usually 1–2 mm from the base; seeds rounded in profile with an indumentum of wispy hairs that are not regularly appressed (see Fig. 3 a)......... H. krichauffianus

Low, spreading dome-shaped or rounded shrub to ~ 0.5 m high, growing on plains with lime-rich soils; leaf lamina 6–28 mm long and 4–16 mm wide, mostly strongly concave to folded or conduplicate in transverse section, the sinus between at least some marginal dentations reaching halfway to the midvein; pedicel abscission point usually in the upper half of the flowering stalk, 2–17(–24) mm from the base; seeds angular in profile with an indumentum of short, rigid appressed hairs (see Fig. 3 c).............. ................................................................................... H. calcareus