Eucalyptus tholiformis

Eucalyptus | Symphyomyrtus | Adnataria | Apicales | Siderophloiae | Subglaucae

Eucalyptus tholiformis A.R.Bean & Brooker, Austrobaileya 4 (2) 188 (1994).

T: Queensland: Salvator Rossa National Park, on ridge east of the Sentinel, 18 May 1986, A.R.Bean 444; holo: BRI; iso: BRI, CANB, MEL.

Tree to 15 m tall. Forming a lignotuber.
Ironbark to the small branches, dark grey to black, sometimes larger branches 10 cm diameter or smaller with smooth white bark.
Juvenile growth (coppice or field seedlings to 50 cm): stem square or rounded in cross-section; juvenile leaves petiolate, alternate, ovate, 4–7 cm long, 2.2–4 cm wide, base rounded or tapering to petiole, dull, blue-grey.
Adult leaves alternate, petiole 1.2–2 (2.4) cm long; blade narrowly lanceolate to lanceolate, 7.5–14 cm long, 1.2–3 cm wide, base tapering to petiole, concolorous, dull, green to blue-green, side-veins normally at an angle less than 45° to midrib, occasionally at a larger angle, very densely reticulate, intramarginal vein parallel to and just within margin, oil glands sparse intersectional or absent.
Inflorescence terminal compound or axillary single umbels below this, peduncles 0.5–1.5 cm long, buds 7 per umbel, sessile or on pedicels to 0.5 cm long. Mature buds obovoid to ovoid or ± cylindrical, 0.5–0.8 cm long, 0.2–0.5 cm wide, scar usually present (outer operculum sheds very early in bud development), operculum bluntly conical to rounded, stamens irregularly flexed, all fertile, anthers cuboid, adnate, slits or pores separate, style long, stigma blunt or pin-head shaped, locules 4, the placentae each with 4 vertical ovule rows. Flowers white.
Fruit sessile or on pedicels to 0.6 cm long, cup-shaped to funnel-shaped, 0.5–0.7 cm long, 0.4–0.7 cm wide, disc raised-convex to oblique to annular or level, valves 4, exserted.
Seeds brown, 1–2 mm long, flattened-ovoid, dorsal surface shallowly reticulate, hilum ventral.

Cultivated seedlings (measured at ca node 10): cotyledons oblong to reniform; stems square in cross-section; leaves always petiolate, opposite for 4–6 nodes then alternate, broadly lanceolate, 7.5–11 cm long, 3–7 cm wide, base tapering, margin entire, apex pointed, slightly discolorous, dull, grey-green.

Flowering has been recorded in May, June, August, September and October.

An ironbark tree restricted to an area centred around the Salvator Rosa National Park in central Queensland from west of Alpha to east of Tambo to just south-west of Springsure.

Eucalyptus tholiformis is closely related to E. ophitica, E. taurina and E. beaniana. All four species have more or less oblong to fusiform buds with a blunt conical to rounded operculum. They are separated by the shape and size of their juvenile leaves. E. tholiformis has ovate juveniles 2.2–4 cm wide, E. ophitica has broad lanceolate juveniles 3–7 cm wide, E. taurina has lanceolate juveniles 1.4–3 cm wide and E. beaniana has linear juveniles 0.4–0.6 cm wide.

Eucalyptus tholiformis is also regarded as being closely related to E. fibrosa [See Bean & Brooker, Austrobaileya 4 (2) 188 (1994)]. E. fibrosa differs by having a long, acute operculum and larger juvenile leaves.

Within its area of occurrence E. tholiformis may be confused with E. crebra and E. decorticans. It differs from E. crebra by having much broader adult and juvenile leaves, more elongated buds with a round operculum, and fruit with slightly exserted valves. E. decorticans differs by having diamond-shaped buds with an acute operculum.

All other ironbark species in the area of occurrence belong to the group of ironbarks where the buds have regularly flexed stamens and have an outer whorl of staminodes (infertile stamens), so that if in bud they can be easily distinguished.

MORE ABOUT IRONBARKS

Eucalyptus tholiformis: Latin tholiformis, dome-shaped, referring to the domed disc of the fruit.