Eucalyptus | Symphyomyrtus | Bisectae | Glandulosae | Erectae | Abundae
Eucalyptus occidentalis var. eremophila Diels in L.Diels & E.Pritzel, Bot. Jahrb. Syst. 35: 442 (1904). T: near Coolgardie, L.Diels 5237; lecto: NSW.
Bark smooth throughout, pale brown-grey and satiny pale grey.
Branchlets with oil glands in the pith.
Juvenile growth (coppice or field seedlings to 50 cm): stems rounded in cross-section; juvenile leaves always petiolate, alternate, oblong-elliptic to lanceolate, 3–9 cm long, 0.8–2.5 cm wide, green, glossy.
Adult leaves often held erect, alternate, petioles 0.5–1.8 cm long; blade narrowly lanceolate to elliptical, (4.5)5–11 cm long, 0.5–2.5 cm wide, base tapering to petiole, margin entire, apex pointed, concolorous, green and glossy, the surface appearing "glazed", side-veins acute or obscure, reticulation invisible, intramarginal vein present or obscure, oil glands numerous, round.
Inflorescence axillary unbranched, pendulous, peduncles flattened, 1.5–4 cm long, buds 7, 9 or 11 per umbel, pedicels 0.4–1.1 cm long. Mature buds elongated, 2.2–3(3.8) cm long, 0.5–0.7 cm wide (asymmetrically fusiform), scar present (outer operculum shed early), operculum horn-shaped, stamens erect, anthers oblong, versatile, dorsifixed, dehiscing by longitudinal slits, style long and straight, stigma rounded or slightly dilated, locules 4, the placentae each with 4 vertical rows of ovules. Flowers lemon-yellow (rarely pale pink).
Fruit down-turned, pedicellate (pedicels 0.5–1.2 cm long), cupular to stoutly barrel-shaped, 0.8–1.4 cm long, (0.6)0.7–1.2 cm wide, disc descending, obscured by persistent staminophore, valves 4, tips at rim level.
Seeds brown to grey-brown, 0.7–2 mm long, ovoid to flattened-ovoid, dorsal surface clearly and shallowly reticulate, hilum ventral.
Cultivated seedlings (measured at node 10): cotyledons Y-shaped (bisected); stems rounded in cross-section; leaves always shortly petiolate, opposite for 2 or 5 nodes then alternate, ovate to lanceolate, 3–11.5 cm long, 1.5–3 cm wide, dull, greyish green becoming green at upper nodes.
Flowering has been recorded in August, September, October, November and December.
A mallet species (i.e. lacking a lignotuber), endemic to Western Australia, occurring from the east of the southern wheatbelt towards Salmon Gums and beyond into more arid areas as far as Coolgardie, Zanthus, Balladonia, Mt Ragged. The small trees are smooth-barked and have glossy, green adult leaves and elongated buds.
Eucalyptus eremophila belongs in Eucalyptus subgenus Symphyomyrtus section Bisectae subsection Glandulosae because the buds have an operculum scar, cotyledons are bisected and branchlets have oil glands in the pith. Within this large subsection (ca 80 species) E. eremophila is closely related to a group of mallees and mallets (series Erectae subseries Abundae) recognised by the glazed leaf surface, leaves with a great density of oil glands that obscures the venation, peduncles long and flattened, inflorescences spreading and buds with a long operculum and erect stamens.
The 14 species in subseries Abundae are loosely grouped as follows. There are five species here considered to form the E. eremophila group—E. depauperata, E. eremophila, E. incerata, E. tenera and E. tephroclada. All have non-ridged buds and fruit, which separates them from the following species, E. goniocarpa, E. platypus, E. utilis, E. mimica, E. steedmanii and E. alipes. E. suggrandis , whilst generally non-ridged, has much smaller buds than the five species of the E. eremophila group, and has warty opercula. E. spathulata and E. orthostemon also have non-ridged small buds very narrowly linear leaves.
The five species in the E. eremophila group are segregated by size of buds and fruit, and presence and absence of white wax on stems, leaves, buds and fruit. The non-glaucous mallet E. eremophila and the heavily waxy mallee E. incerata have the largest buds and fruit and occur generally to the east of the southern wheatbelt with E. eremophila being the only species in the group to extend into desert areas.
Two mallee species, the non-glaucous E. tenera and the slightly waxy E. tephroclada, have very similar slender buds and fruit that are generally smaller than in typical E. eremophila. The only difference between E. tenera, which is widespread in the southern and central wheatbelt, and E. tephroclada, more restricted to the Hyden-Southern Cross area, is the presence of white wax in the latter.
The fifth species, E. depauperata, is a slender non-glaucous whipstick mallee "distinguished within the E. eremophila group by the small leaves, buds and fruits" (Hill & Johnson, 1991), which, even at its type locality south-east of Lake King, grows with plants that look more like E. tenera.
Whilst the five species that now make up the E. eremophila group are included in this edition of EUCLID it is not always possible to assign individual plants to one or other of the names with certainty.