Australian Journal of
Taxonomy
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WA: Nylagarda Road c. 0.15 km S of Jurien Road East, 23 August 2020, K.R. Thiele 5641 (holo: PERTH 9261680; iso: AD, CANB, MEL)
Figure 7. Distributions of Hibbertia ericoides (A) and H. williamsiorum (B) in southwestern Western Australia.
Erect, compact, sometimes sprawling shrubs to 0.6 m high, multi-stemmed at base and resprouting after fire; young branchlets glabrous except for tufts of short hairs in the leaf axils. Leaves spreading, scattered, narrowly oblong to narrowly ovate, 5–8 mm long, 1–1.5 mm wide, thick-textured, usually shallowly incurved, the margins strongly recurved to the broad, prominent midrib and obscuring the abaxial surface; adaxial surface obscurely tuberculate, glabrous or with minute, sub-stellate hairs from the tubercles and sometimes with very few, minute cilia along the margin of the petiole; abaxial surface densely papillate where visible along either side of the smooth midrib; apex tapering to a straight, subacute apex formed by the excurrent midrib. Flowers sessile, terminating short-shoots or main stems; flower-subtending bracts 6–10, ovate to narrowly triangular, ±herbaceous to chartaceous, 3–4 mm long, acute, glabrous except the minutely ciliolate margins, the lowermost grading to leaves. Sepals 5, ovate, 5.5–8 mm long; midribs not prominent; outer sepals acute, glabrous but sometimes with a minutely ciliolate margin; inner sepals similar in size and apex shape to the outer but broader, slightly thinner, and with scattered, minute sub-stellate hairs. Petals 5, yellow, broadly obovate, 5.5–8 mm long, emarginate. Stamens 10(11), all on one side of the gynoecium and curving over it like a hand of bananas; filaments 0.6–1.2 mm long, fused at the base into a robust claw; anthers rectangular, 1.8–2 mm long, dehiscing by introrse, longitudinal slits. Staminodes (1)2(–4) either side of the stamens. Carpels 2; ovaries compressed-globular, densely pubescent; styles inserted excentrically on the carpel apex, parallel and curved beneath the stamens, 0.6–1.2 mm long. Ovules 2 per carpel. Fruiting carpels and seeds not seen.
Other specimens examined (all PERTH): Coomallo (5320976, 5717825, 9330232), Eneabba (3069699, 3069702, 3069214, 9330275), Hill River (9330356), Lesueur National Park (3043126, 4067479, 9469575), Warradarge (4569717, 6316700, 9330283). For full specimen details, see the following batch search of the ALA for this set of specimens: https://biocache.ala.org.au/occurrences/search?q=qid:1665056668160#tab_mapView
Figure 7. Distributions of Hibbertia ericoides (A) and H. williamsiorum (B) in southwestern Western Australia.
Diagnostic features. Distinctive within the Hibbertia crassifolia-H. aurea species group in having thick-textured, short, relatively broad leaves (5–8 mm × 1–1.5 mm) that are usually adaxially glabrous, with the lamina tightly abutting the thick, prominent midrib, the abaxial surface (where visible) densely papillate, and flowers with 6–10, ovate to narrowly triangular, ±herbaceous to chartaceous bracts.
Phenology. Flowers from May to September.
Distribution & habitat. Hibbertia ericoides occurs over a relatively narrow range (c. 45 km north to south) north-east of Jurien Bay, approximately between Eneabba and Coomallo Nature Reserve (Fig. 7), in low kwongan heath over laterite. It tends to occupy slightly more elevated, drier sites than the superficially very similar H. williamsiorum.
Conservation status. Despite its narrow range H. ericoides grows in a number of national parks and nature reserves and is not considered to be at risk.
Etymology. From the genus name Erica and the Greek suffix -oides (similar to), in reference to the small, hard, ericoid leaves.
Notes. Superficially very similar to H. williamsiorum, from which it is most readily distinguished by its floral bracts, which are herbaceous to chartaceous, pale-coloured, ± half the length of the calyx, persistent, narrowly ovate to narrowly triangular, and tapering evenly to an acute apex. The bracts in H. williamsiorum, by contrast, are scarious, brownish to chestnut, more than half the length of the calyx, readily deciduous, and broadly ovate with an acuminate apex, the margins in at least some bracts rather abruptly shouldered below the apex. The bracts in both species have white-ciliolate margins, but because of the difference in colour the cilia are more prominent in H. williamsiorum than in H. ericoides. There is also a subtle difference in habit in the field, with H. williamsiorum having a slightly stouter habit with the flowers borne on shorter, stouter short-shoots, and slightly broader leaves.
Prior to this treatment, specimens of H. ericoides were assigned to either H. crassifolia or H. aurea (to the latter on account of the relatively acute leaves formed from the excurrent midrib), substantially confusing the boundary between those two species.