Eucalyptus coronata

Crowned mallee

Eucalyptus | Eucalyptus | Longistylus | Frutices | Preissianae | Glandulares

Eucalyptus coronata C.A.Gardner, J. Proc. Roy. Soc. W. Australia 19: 86 (1933); non Maiden (1902), nom. inval.

Eucalyptus mitrata C.A.Gardner, J. Proc. Roy. Soc. W. Australia 22: 127 (1936). T: Middle Mt Barren, W.A., Sept. 1926, C.A.Gardner 1914; syn: PERTH; near East Mt Barren, W.A., Dec. 1931, H.Steedman s.n.; syn: PERTH; Whoogarup Range, W.A., 28 Nov. 1931, C.A.Gardner 2971; isosyn: K.

Mallee to 3 m tall. Forming a lignotuber.
Bark wholly smooth, pale grey and pale brown.
Branchlets lacking oil glands in the pith.
Juvenile growth (coppice or wild seedling to 50 cm tall) not seen.
Adult leaves alternate, petioles 1.2–2.8 cm long; blade lanceolate to falcate, 7–13 cm long, 1.3–2.5 cm wide, base tapering to petiole or sometimes oblique, margin entire, apex pointed, side-veins at an acute or wider angle to midrib, reticulation dense, intramarginal vein remote from margin, oil glands few, intersectional.
Inflorescence axillary unbranched, peduncles broadly flattened, 1–1.7 cm long, buds 3 per umbel, sessile or pedicellate (pedicels 0–0.2 cm long). Mature buds ± diamond-shape with numerous pronounced ribs, 2.7–3 cm long, 2.2–2.3 cm wide, scar absent, the single operculum beaked, stamens mostly arranged obliquely, a few inner stamens inflexed, anthers oblong, versatile, dorsifixed, dehiscing by longitudinal slits (non-confluent), style not quite as long as floral cavity, straight, stigma rounded, locules 4 or 5, the placentae each with 2 vertical rows of ovules. Flowers white.
Fruit sessile or on pedicels to 0.4 cm long, broadly obconical and prominently ribbed, 1.7–2.5 cm long, 3.2–5.3 cm wide (including ribs), disc lobed over the 4 or 5 valves.
Seeds blackish, 3–6 mm long, pyramidal to cuboid, dorsal surface smooth or irregularly wrinkled, hilum terminal.

Cultivated seedlings (measured at ca node 10): cotyledons large, reniform; stems rounded to square in cross-section, scabrid throughout; leaves opposite and sessile for at least 10 nodes, broadly ovate, 5–9.5 cm long, 3–5 cm wide, bases amplexicaul becoming rounded higher up stem, margins irregular ("crinkled") and scabrid, apex blunt, discolorous, dull to slightly glossy, mid-green.

Flowering time not recorded.

A small mallee endemic to Western Australia. It is found only in heathland on coastal hills from Middle Mount Barren to East Mount Barren, Fitzgerald River National Park. The bark is smooth and the adult leaves green and slightly glossy, the buds in groups of three.

Eucalyptus coronata belongs in Eucalyptus subgenus Eucalyptus series Preissianae, a small group characterised by smooth bark, buds in threes, buds with a single operculum (hence no operculum scar), cuboid anthers that shed pollen by two separate slits, ovules arranged in two rows on the placenta, fruit that are large with the disc lobed over the valves, seed pyramidal to cuboid and seedlings with sessile, opposite leaves for at least 10 nodes. 

Series Preissianae has 4 species viz. E. aquilina, E. preissiana, E. coronata and E. megacarpa. One of the species, E. preissiana, has yellow flowers and brown seeds while the other three species have white flowers and black seeds. E coronata is distinguished amongst them by the strongly ribbed buds and fruit 3.2–5.3 cm wide (including ribs).

Eucalyptus coronata is listed as "Vulnerable" under the Australian Government Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). Further information may be found at this web address:
http://www.environment.gov.au/cgi-bin/sprat/public/sprat.pl

Eucalyptus coronata: Latin coronatus, crowned, referring to the sculptured opercula.