Eucalyptus rosacea

Eucalyptus | Symphyomyrtus | Bisectae | Destitutae | Curviptera | Synandrae

Eucalyptus rosacea L.A.S.Johnson & K.D.Hill, Telopea 4: 623–4 (1992).

T: Western Australia: 12.0 km S of Queen Victoria Spring on Cundeelee road, 30 Nov. 1986, K.D.Hill 2686 & L.A.S.Johnson; holo: NSW; iso: CANB, MEL, PERTH.

Mallee to 4 m tall. Forming a lignotuber.
Bark smooth throughout, dark and light grey over pinkish grey or yellow-grey and white.
Branchlets not glaucous; lacking oil glands in the pith.
Juvenile growth (coppice or field seedlings to 50 cm): stems rounded in cross-section; juvenile leaves sessile to shortly petiolate, alternate, linear, 3.5–8 cm long, 0.2–0.4 cm wide, dull, grey-green.
Adult leaves more or less erect, alternate, petioles 0.4–1 cm long; blade linear to narrowly oblong, (4.5)6–12 cm long, 0.5–1 cm wide, base tapering to petiole, margin entire, apex pointed, concolorous, dull, grey-green to bluish green, side-veins greater than 45° to midrib, reticulation dense, intramarginal vein close to margin, oil glands intersectional.
Inflorescence axillary unbranched, pendulous, peduncles 1–3 cm long, buds (3)7, pedicellate, pedicels 0.7–1 cm long. Mature buds ovoid (1.1–1.7 cm long, 0.6–0.7 cm wide), scar present, operculum slenderly beaked (0.9–1.5 cm long), stamens connate into a tube for about half their length, a few outer filaments erect, remainder inflexed to varying degrees, anthers oblong, versatile, dorsifixed, dehiscing by longitudinal slits, style long and straight, stigma blunt to tapered, locules 4 or 5, the placentae each with 4 vertical rows of ovules. Flowers pink, sometimes cream or red.
Fruit pedicellate, pedicels 0.8–1.1 cm long, shallowly hemispherical-obconical to almost saucer-shaped, 0.3–0.5 cm long, 0.6–1.2 cm wide, disc raised obliquely or convex, valves 4 or 5, rim level to exserted.
Seeds brown, 1–2 mm long, angularly ovoid, scarcely ridged ventrally, dorsal surface shallowly reticulate, hilum ventral to more or less terminal.

Cultivated seedlings (measured at node 10): cotyledons bisected; stems rounded in cross-section; leaves sessile to subsessile, opposite for 6 to 8 nodes then alternate, linear, 3.5–10 cm long, 0.2–0.6 cm wide, dull, green.

Flowering has been recorded in December.

A mallee endemic to Western Australia, found east of Laverton and Queen Victoria Springs towards Neale Junction in the Great Victoria Desert. The stems are smooth, the adult leaves linear, dull, grey-green and the buds pendulous and with the finely pointed operculum much longer than the very short bud base.

Eucalyptus rosacea belongs in Eucalyptus subgenus Symphyomyrtus section Bisectae subsection Destitutae because buds have two opercula, cotyledons are Y-shaped and branchlets lack oil glands in the pith. Within this subsection E. rosacea is in series Curviptera, and is one of about 30 closely related species and subspecies which are further characterised by having large buds in umbels of one, three or seven, staminal filaments erect or oblique (rarely inflexed) in bud, and large fruit usually with an ascending disc and exserted valves.

Within series Curviptera this species has only two close relatives, E. beardiana and E. synandra. All three species have an unusual feature that occurs nowhere else in the genus Eucalyptus—the stamens are united basally into a short tube. E. rosacea has non-powdery bark and linear leaves shorter than in E. synandra, cream to pink or red flowers, and fruit with a moderately ascending disk. E. beardiana is found only south of Shark Bay to Wannoo, has non-powdery bark, yellow flowers and fruit with an almost flat disk. E. synandra, which is of rare occurrence in the eastern part of the northern wheatbelt from Morowa south-east to Karroun Hill, differs from E. rosacea by the powdery white bark, sprawling habit, much longer leaves, the fruit with a strongly ascending disc and white to pink flowers.

Eucalyptus rosacea is difficult to tell from E. leptopoda except when in flower, being similar in habit, leaf and fruit features. The creamy white stamens of E. leptopoda are never united basally into a tube. E. synandra has longer leaves (to 17 cm) and a more open crown.

Eucalyptus rosacea: Latin rosaceus, pink, referring to the colour of the flowers.