Hibiscus sp.

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 : 475-476

Hibiscus sp. , Belele (D.W.Goodall 3417) McLay & Albr

Note: the description below is tentative, and presented to facilitate recognition and the collection of additional specimens and associated data. This is based on very limited material and should only be considered a draft description requiring modification as more specimens become available.

Subshrub to ~ 0.3 m tall. Branchlets very densely covered with sessile to shortly stalked stellate hairs, indumentum white on young branchlets, becoming ferruginous. Stipules persistent or abscising with age, filiform to filiform–subulate, 1.5–3.5 mm long, 0.2–0.32 mm wide. Mature leaves simple and unlobed, petiolate; petiole 6–16 mm long, moderately to very densely covered with sessile or shortly stalked stellate hairs; lamina ovate to elliptic ovate, flat to weakly folded, 17–43 mm long, 6–22 mm wide; base truncate, very slightly cordate, or broadly obtuse; margins dentate to crenate; apex obtuse to broadly acute; adaxial surface silvery–ferruginous, abaxial surface usually paler (except in young leaves); abaxial main and lateral veins raised and very obvious; stellate hairs on adaxial surface dense to very dense (rarely moderate); stellate hairs on abaxial surface dense to very dense, ferruginous hairs more prominent on veins. Flowers solitary in leaf axils; combined peduncle and pedicel 8–19 mm long, broadening distally, abscission line not always distinct, approximately one-third of the length from the base, indumentum as on young stems and petioles. Epicalyx lobes 5–6, linear, 6–12 mm long, one-half to three-quarters the length of the calyx at anthesis, free or very slightly fused basally for ~ 1 mm, recurved in fruit, with dense stellate hairs abaxially on the lobes. Calyx 10.5–17 mm long at anthesis; lobes narrowly triangular to triangular, 7–10 mm long in fruit, abaxial indumentum of moderate to very dense stellate hairs, adaxial indumentum of ascending 1-few armed hairs intermixed with stellate hairs particularly distally. Petals 39–42 mm long, adnate to staminal column at base but otherwise free, apparently purple, glabrous adaxially, with sparse to moderate stellate hairs abaxially towards the margin and apex on one side. Staminal column ~ 20 mm long, apex irregularly 5-lobed, with the stamens distributed singly along the distal ~ 5 mm of the column; staminal filaments ~ 4 mm long; anthers yellow. Style 5-branched, with branches ~ 3 mm long, exserted ~ 5 mm beyond the apex of the staminal column. Stigmas capitate, ~ 0.5 mm wide, distinctly hairy, hairs ~ 0.4 mm long. Ovary 5-locular, with hairs. Capsule ovoid, 13–17 mm long, usually beaked, beak ~ 1 mm long, densely covered with simple shiny appressed hairs, the apical hairs erect, 0.8–1 mm long and extending beyond apex of capsule. Seeds angular–reniform with the two abaxial sides flat to convex, ~ 3 mm long and almost forming a right angle at the junction, dark brown, short patchy indumentum of appressed white–yellowish simple hairs, ~ 0.25 mm long; funicular remnants brown, membranous and wing-like, on either side of the hilum. ( Fig. 2 d , 3 d .)

Distribution

Western Australia, IBRA Bioregions of Murchison and Yalgoo ( Fig. 1 , black crosses).

Phenology

The limited herbarium material available indicates that the entity flowers in April, producing fruit in July and October.

Affinities

Hibiscus sp. Belele (D.W.Goodall 3417) is similar to H. krichauffianus and H. calcareus and these are likely closely related or sister taxa. Based on the limited material available, H. sp. Belele (D.W.Goodall 3417) appears to be distinct in having ferruginous hairs on older branchlets and leaves (cf. predominantly silvery-white or white in H. krichauffianus and H. calcareus ), and apparently deeper coloured petals (recorded as purple) that are large (petals 39–42 mm long, cf. 17–35 mm in H. krichauffianus and 20–44 mm in H. calcareus ). The leaf margins resemble those of plants of H. krichauffianus , being less deeply incised than those in H. calcareus ; however, the seeds are angular and have appressed hairs, resembling H. calcareus rather than H. krichauffianus . The five specimens of H. sp. Belele (D.W.Goodall 3417) are also significantly geographically isolated from the current known ranges of H. krichauffianus or H. calcareus , with over 1000 km between collections ( Fig. 1 ).

Specimens examined (five specimens seen)

WESTERN AUSTRALIA: Cliffs Natural Resources Mount Richardson, ~ 138 km NW of township of Ularring, 7 Sep. 2012, D.Coultas Opp-48 ( PERTH); Woolorong Station , 7 Apr. 1999, M. Officer 214 ( PERTH); Gidgee Station ( I447 ), 20 July 1993, H. Pringle 3683 ( PERTH); Belele Station , WNW of Meekatharra , 26 & 30 Oct. 1965, D.W. Goodall 3417 ( PERTH); Yuin, 1888, S. J. B. Hymus s.n. ( MEL 2223356 A) .

Figures

Fig. 2. Example herbarium specimens of the four morphotypes of H. krichauffianus sens. lat. (a) Morphotype A Hibiscus krichauffianus sens. strict. (voucher: C.J.Brodie & P.J.Lang 3402, AD 249644); (b) morphotype B Hibiscus verecundus (voucher: R.J.Fensham 2991, BRI AQ653057); (c) morphotype C Hibiscus calcareus (voucher: P.Hudson s.n., AD 98321044); and (d) morphotype D Hibiscus sp. Belele (voucher: D.W.Goodall 3417, PERTH 3427285). Scale bar: 2 cm.

Fig. 3. Seeds of the four morphotypes. (a) Morphotype A Hibiscus krichauffianus sens. strict. (voucher: C.J.Brodie & P.J.Lang 3402, AD 249644); (b) morphotype B Hibiscus verecundus (voucher: R.J.Fensham 2991, BRI AQ653057); (c) morphotype C Hibiscus calcareus (voucher: P.Hudson s.n., AD 98321044); and (d) morphotype D Hibiscus sp. Belele (voucher: D.W.Goodall 3417, PERTH 3427285). Scale bar: 1 mm.

Fig. 1. Distribution map for the four morphotypes of H. krichauffianus sens. lat. in Australia. Distributions are based only on material viewed by the authors. Morphotype A: Hibiscus krichauffianus sens. strict., grey squares; Morphotype B: Hibiscus verecundus, orange circles; Morphotype C: Hibiscus calcareus, blue triangles; Morphotype D: Hibiscus sp. Belele (voucher: D.W.Goodall 3417), black crosses.