Australian Journal of
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Hibbertia cadens K.R.Thiele sp. nov.
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Type: Albany Highway 0.3 km S of Wearne Road, 22 September 2019, K.R. Thiele 5579 (holo: PERTH 9187286; iso: xxxxxxxx)

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Sprawling to semi-erect shrubs to 0.2 m high, spreading to 0.3 m, the stems erect at first becoming decumbent with age, resprouting after fire; branchlets with sparse, pilose hairs over a shorter, moderately dense pubescence, tardily glabrescent; older stems decorticating in papery strips. Leaves spreading, scattered, broadly elliptic to broadly obovate, (15–)20–30(–40) mm long, 10–20 mm wide, with a few short, blunt teeth in the upper half, flat but the margins slightly thickened; adaxial surface sparsely pilose with spreading hairs to 3 mm long over a sparse pubescence of short, erect hairs 0.1–0.2 mm long; abaxial surface as for abaxial but the hairs sparser, pale green to pale grey beneath the indumentum; apex obtuse. Flowers sessile, axillary, subtended by 4–6 dark brown to blackish, scarious, broadly ovate, obtuse to apiculate, glabrous (lowermost sometimes minutely pubescent) bracts to 10 mm long. Sepals ovate, 8–10 mm long, abaxially densely silvery appressed-pubescent with hairs to 0.3 mm long and with white, pilose hairs to 2 mm long restricted to the margin in the lower half, adaxially moderately to densely finely appressed-pubescent throughout; midribs not prominent; outer sepals acute to broadly and shortly acuminate; inner sepals similar to the outer in size, shape, apex and indumentum but broader; buds acute to very shortly rostrate. Petals yellow, obovate, 12–18 mm long, emarginate. Stamens 50–65, distributed evenly around the gynoecium, free; filaments 2–2.5 mm long, closely appressed to the gynoecium; anthers oblong to rectangular, 0.6–1.5 mm long, dehiscing by short, introrse, longitudinal slits near the apex. Staminodes and reduced stamens sometimes present. Carpels 3 or 4; ovaries globular, densely pubescent; styles excentrically spreading-erect from near the carpel apex, 2.5–3 mm long. Ovules 2 per carpel. Seeds not seen.

Diagnostic features. Text here

Phenology. Text here

Distribution & habitat. Text here

Conservation status. Text here

Etymology. From the Latin cado (to fall), in reference to the sprawling habit.

Notes. While Hibbertia cadens is clearly distinct from H. hortiorum in the field, herbarium specimens of these two species may be difficult to discriminate without adequate label information. Hibbertia hortiorum is mat-forming, with many prostrate stems (which produce some adventitious roots at the nodes) forming a tangled mass. By contrast, stems of H. cadens are fewer in number and are clearly erect at first, though they often sprawl and become somewhat decumbent with age. The leaves of H. cadems are slightly larger on average than H. hortiorum (mostly 20–30 mm long cf. mostly 15–25 mm long), but the ranges overlap. The hairs on the backs of the sepals of H. cadens are slightly longer, denser and more white than most specimens of H. hortiorum (from the Monadnocks Conservation Park); however, plants of H. hortiorum from the North Bannister-Wandering Road also have longer hairs on the sepal backs, particularly towards the base.