Eucalyptus tenera

Sand mallee

Eucalyptus | Symphyomyrtus | Bisectae | Glandulosae | Erectae | Abundae

Eucalyptus tenera L.A.S.Johnson & K.D.Hill, Telopea 4: 586 (1992).

T: Western Australia, Bencubbin, 16 Mar 1984, M.I.H.Brooker 8493; holo: NSW: iso: AD, CANB, MEL, PERTH.

Mallee to 5 m tall. Forming a lignotuber.
Bark smooth throughout, pale brown-grey, tan and satiny pale grey.
Branchlets have oil glands in the pith.
Juvenile growth (coppice or field seedlings to 50 cm): stems rounded in cross-section; juvenile leaves always petiolate, alternate, linear to oblong-elliptic to narrowly lanceolate, 3–9 cm long, 0.7–2.5 cm wide, green, glossy.
Adult leaves held more or less erect, alternate, petioles 0.5–1.8 cm long, narrowly lanceolate to elliptical, 4–9 cm long, 0.7–2.5 cm wide, base tapering to petiole, margin entire, apex pointed, concolorous, glossy, green, 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, 1.8–3 cm long, ?(7 or 9) to11-flowered; buds pedicellate (pedicels 0.5–0.9 cm long). Mature buds elongated and widest below the join, 2.8–4 cm long, 0.5–0.6 cm wide, scar present (outer operculum shed early), operculum slender and 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.
Fruit down-turned, pedicellate (pedicels 0.2–0.7 cm long), cupular to stoutly barrel-shaped, 0.7–1 cm long, 0.6–1.1 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 to 5 nodes then alternate ovate to lanceolate, 7–11.5 cm long, 2–3 cm wide, dull, greyish green becoming green at upper nodes.

Flowering has been recorded in November.

A mallee endemic to Western Australia, occurring in the central wheatbelt and western part of the southern wheatbelt, from Coorow south to Nyabing and east to Chiddarcooping and Lake King, on sandy sites. The stems are smooth-barked and the adult leaves glossy, green.

Eucalyptus tenera 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. tenera is closely related to a group of mallees and mallets (series Erectae subseries Abundae, 14 species) recognised by the glazed leaf surface, leaves with a great density of oil glands that obscures the venation, peduncles long and flattened, inflorescences spreading to pendulous 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 E. goniocarpa, E. platypus, E. utilis, E. mimica, E. steedmanii, and E. alipes. E. suggrandis, whilst weakly or non-ridged, has much smaller buds with +/- warty opercula. E. spathulata and E. orthostemon also have non-ridged buds that are small, as well as very narrowly linear leaves.

The five species of 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 two mallee species, the non-waxy E. tenera and the white waxy E. tephroclada, have very similar slender buds and fruit that are generally smaller than in E. eremophila and E. incerata. The only difference between E. tenera and E. tephroclada, which is more restricted to the Hyden-Southern Cross area, is the presence of white wax on the branchlets and inflorescences of the latter.

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.

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 like E. tenera.

Whilst the five species that now make up the E. eremophila group are all included in this edition of EUCLID it is not always possible to assign individual plants to one or other of the names with certainty.

Eucalyptus tenera: Latin tener, delicate, referring to the smaller buds and fruit than those of the related E. eremophila.