Eucalyptus articulata Brooker & Hopper, Nuytsia 9: 14 (1993).
T: 22 km E of Mulga Rock, Great Victoria Desert, 30°09'S,
25 June 1987, M.I.H.Brooker 9686 & S.D.Hopper; holo: PERTH;
iso: AD, CANB, MEL, NSW.
Mallee to 3 m tall. Forming a lignotuber.
Bark smooth throughout, coppery or bronze.
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,
opposite for few nodes then alternate, broadly lanceolate, 6-12 cm
long, 1-1.5 cm wide, dull, blue-green (non-glaucous).
Adult leaves alternate, petioles 0.8-1.8 cm long;
blade lanceolate, 6-12 cm long, 1-1.5 cm
wide, base tapering to petiole, margin entire, apex acute, concolorous,
glossy, dark green, side veins acute, reticulation sparse to moderate,
intramarginal vein remote from margin, oil glands numerous, island,
Inflorescences axillary unbranched, or at times apparently
terminal due to loss of apical vegetative bud, peduncles flattened,
0.5-1.5 cm long; buds 7, stoutly pedicellate, obovoid to pyriform,
scar present, operculum rounded and sometimes apiculate or bluntly
conical, stamens inflexed with their filaments geniculate, anthers
cuboid, versatile, sub-basifixed, dehiscing by longitudinal slits,
style long and straight, the base tapering and articulate in a pit
in the ovary roof, stigma blunt to rounded, locules 3 or 4, the placentae
each with 4 vertical rows of ovules; flowers white.
Fruit pedicellate, obconical or at times almost cylindrical,
0.4-0.6 cm wide, disc descending vertically, valves 3 or 4, enclosed
to near rim level.
Seed brown, 0.7-1.5 mm long, ovoid to flattened-ovoid or cuboid
but scarcely angular, dorsal surface shallowly reticulate, hilum ventral.
Cultivated seedling (measured at ca node 10): cotyledons Y-shaped
(bisected); stems rounded in cross-section; leaves always petiolate,
opposite for 3 to 6 nodes, lanceolate, 5-10 cm long, 1.2-3 cm wide,
green, slightly glossy.
Eucalyptus articulata (Latin, articulatus, articulate
or jointed, referring to the style base).
A low straggly mallee endemic to Western Australia, known only from
near Mulga Rock, north-east of Kalgoorlie, where it occurs on red
sand dunes with arkose rubble. The bark is smooth, bright coppery
in season, and the adult leaves are very glossy green with sparse
venation and conspicuous oil glands.
Eucalyptus articulata belongs to Eucalyptus subgenus
Symphyomyrtus section Bisectae subsection Glandulosae
because the cotyledons are bisected, buds have an operculum scar
and the branchlets have oil glands in the pith. Within this subsection
E. articulata belongs to a small subgroup of four species,
series Loxophlebae, further characterized by having buds with
fully inflexed stamens with the filaments geniculate or strongly elbowed
and a style that tapers basally, sparsely reticulate glossy green
adult leaves and small obconical fruit. The four species are E.
loxophleba (with 4 subspecies), E. blaxellii , E. articulata
and from north-east of Meekatharra (beyond the scope of this edition
of EUCLID) E. semota.
Eucalyptus articulata is unlikely to be confused with any other
species within its natural range. Its geographically closest relative
is the smooth-barked E. loxophleba subsp. lissophloia
which is distinguished from E. articulata by having glaucous
branchlets and glaucous, more or less deltoid, juvenile leaves. E.
articulata has blue-green (non-glaucous) lanceolate juvenile leaves
and non-glaucous branchlets. The style base of E. articulata is
articulate where it is inserted in a pit in the ovary roof, a character
absent from E. loxophleba , but present also in E. semota
and E. blaxellii.