Eucalyptus lehmannii (Schauer) Benth., Fl. Austral. 3: 233 (1867).

Symphyomyrtus lehmannii Schauer in J.G.C.Lehmann, Pl. Preiss. 1: 127 (1844). T: Cape Riche, W.A., 19 Nov. 1840, L.Preiss 227; lecto: LD n.v., fide D.J.Carr & S.G.M.Carr, Austral. J. Bot. 28: 531 (1980); isolecto: G, MEL.

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Description

Mallee to 3 m tall, stems slender. Forming a lignotuber.
Bark smooth throughout, whitish grey to grey-brown and orange-brown shedding in strips.
Branchlets lacking oil glands in the pith.
Juvenile growth (coppice or field seedlings to 50 cm)
: stems triangular in cross-section near the growing tips but soon becoming rounded, warty to scabrid on fresh young growth but soon smooth; juvenile leaves always petiolate, alternate, oblong to elliptical or lanceolate, 58 cm long, 13 cm wide, lower leaves dull blue-green, upper leaves glossy, green, not scabrid.
Adult leaves alternate, petioles 0.11.5 cm long; blade elliptical to oblong or obovate, (3.7)4.59.5 cm long, 0.72.8 cm wide, base tapering to petiole, margin entire, apex pointed or rounded, concolorous, glossy, light to mid-green, side-veins at an acute or wider angle to midrib, reticulation usually sparse to moderate, intramarginal vein conspicuous and remote from margin such that it sometimes appears to have 3 main veins, oil glands obscure or scattered, intersectional.
Inflorescences axillary unbranched, peduncles flattened, down-curved by time of flowering, 411 cm long; buds?1119 or more per umbel which is syncarpous (all or most of the buds in the umbel joined by their bases or hypanthiums, the upper part of each bud remaining free). Buds syncarpous (all of the buds in a cluster are completely joined by the hypanthium only, the upper part of each bud remains free, at maturity the combined length of the fused part plus operculum is ca 3.3-6.5 cm, whilst width of individual buds measured at the base of the operculum is 0.51 cm); scar present but may be difficult to see at bud maturity as outer operculum is lost early, operculum often curved, 5 to 8 times as long as the fused part of the bud, stamens completely erect, anthers narrowly oblong, versatile, dorsifixed, dehiscing by longitudinal slits, style long and straight, stigma blunt, locules 3, the placentae each with 4 vertical rows of ovules. Flowers green-yellow.
Fruit on down-turned peduncles, syncarpous, the individual capsules in the woody mass .91.5 cm in wide, length not measurable, dehiscing by elliptical holes formed as the 3 valves split along the sutures but remain connected apically, disc covers the surface of the valves.
Seed black, 23 mm long, ovoid to more or less angularly so, dorsal surface shallowly reticulate, hilum ventral/terminal.

Cultivated seedling (measured at node 10): cotyledons Y-shaped (bisected); stems triangular but soon becoming rounded in cross-section, scabrid; leaves always petiolate, opposite for 26 nodes then alternate, ovate-lanceolate to elliptical or oblong, 37 cm long, 0.83.3 cm wide, dull grey-green to green, lamina scabrid up to about node 6 then becoming smooth.

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Notes

A small mallee endemic to Western Australia, widespread in southern coastal and subcoastal areas from east of Albany towards Israelite Bay, including the Stirling Range. The stems are smooth, the adult leaves glossy green and variable in shape from narrow-lanceolate to short elliptical-oblong, often mucronate. The large pendulous bud and fruit clusters are conspicuous in the crown.

Eucalyptus lehmannii belongs in Eucalyptus subgenus Symphyomyrtus section Bisectae subsection Hadrotes because the cotyledons are coarsely bisected, buds have an operculum scar, a long (inner) operculum and erect stamens, fruit are large, thick-rimmed and held rigidly. Of the ten species in subsection Hadrotes eight lack oil glands in the pith of the branchlets and have scabrid seedlings. Together these eight species form series Lehmannianae, a group further characterized by having fruit with exserted valves that remain fused at their tips after seed shed, a feature shared with the more distantly related E. cornuta.

Of the eight species in series Lehmannianae four, E. lehmannii, E. conferruminata, E. mcquoidii and E. arborella, have the buds (and fruit) in each axillary cluster fused basally whilst the other four species, E. newbeyi, E. burdettiana, E. talyuberlup, and E. megacornuta, have buds and fruit free.

E. lehmannii is distinguished from its three close relatives by its mallee habit. It is closest to E. arborella, which differs in being a mallet and in having broader seedling leaves. Both these species have broadly flattened down-turned peduncles, bud clusters of similar size (up to 21 buds per cluster) and opercula that are very long and slender. E. mcquoidii differs in being a non-lignotuberous shrub (marlock) or stunted mallet with terete down-turned peduncles, many more buds per cluster (to ca 50) but with similar graceful slender opercula. E. conferruminata is also a marlock or mallet but has flattened down-turned peduncles, also with up to 21 buds per cluster but stout relatively short opercula (< 5 times as long as wide).

The mallee Eucalyptus bennetiae D.J.Carr & S.G.M.Carr is a well-known, naturally occurring hybrid  found in the Mount Desmond area near Ravensthorpe and also a little further to the south-east of there. Studies by Byrne & Walker (unpubl. report, 2003) showed the parents to be Eucalyptus sporadica and E. lehmanii, as had been suspected. The progeny (seedlings) are known to show morphological segregation reflecting their hybrid origin.

Eucalyptus bennettiae 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.deh.gov.au/cgi-bin/sprat/public/sprat.pl

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Flowering Time

Flowering has been recorded in January, February, May, October and November.

Eucalyptus lehmannii is a decorative ornamental mallee in its own right, not to be confused with E. conferruminata which for many years was sold and planted under the name E. lehmannii.

In Victoria Carr et al. (1992) regard this species as an environmental weed with the potential to pose a risk to heath and associated woodlands, and lowland grassland, noting that it is currently rare or localized in small populations.

Origin of Name

Eucalyptus lehmannii: after Johan Georg Christian Lehmann (17921860). Johan Lehmann was Professor of Botany and Director of the Botanic Gardens in Hamburg, Germany. He was an author of many botanical books.

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