Euclid - Online edition

Eucalyptus mimica subsp. mimica

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Eucalyptus | Symphyomyrtus | Bisectae | Glandulosae | Erectae | Abundae

Eucalyptus mimica Brooker & Hopper subsp. mimica Nuytsia 14: 344 (2002).

T: 11.3 km along Old Ravensthorpe Road from Newdegate – Lake King Road, W.A., 24 Nov. 1987, M.I.H.Brooker 9811; holo: PERTH; iso: AD, CANB, MEL, NSW.
Mallet to 5 m tall. Lignotuber absent.
Bark smooth throughout, shiny pale grey-green over coppery brown.
Branchlets have oil glands in the pith.
Juvenile growth (coppice or field seedlings to 50 cm): not seen.
Adult leaves held erect, alternate, petioles 0–0.6 cm long; blade narrowly elliptical to linear, 3.5–8.5 cm long, 0.4–0.9 cm wide, base tapering to petiole, margin entire or distantly indented, apex finely pointed, concolorous, glossy, green, surface appearing "glazed", usually only the midrib visible, all other venation obscured by numerous oil glands.
Inflorescence axillary unbranched, peduncles 0.7–2 cm long, buds 3. Mature buds more or less obovoid to fusiform (1.2–1.9 cm long, 0.4–0.6 cm wide), pedicellate (pedicels 0.5–0.8 cm long), outer operculum formed but splits early in development into 4 green calyx lobes terminating the 4 angles of the hypanthium (lobes probably remain until flowering but ultimately are deciduous), inner operculum warty, conical to beaked, slightly narrower than the hypanthium at the join, stamens erect, anthers oblong, versatile, dorsifixed, dehiscing by longitudinal slits, style long and straight, stigma blunt to slightly dilated, locules 3 or 4, the placentae each with 4 or 6 vertical rows of ovules. Flowers not seen.
Fruit pedicellate (pedicels 0.5–0.8 cm long), obconical with 3 or 4 angles and curved faces in between, 0.7–1.2 cm long, 0.7–1 cm wide, disc descending, hidden by persistent staminophore, valves 3 or 4, held at rim level or slightly exserted.
Seeds dark brown, 0.7–1.5 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 subsessile to shortly petiolate, opposite for ca 4 or 5 nodes then alternate, linear, 5.5–8 cm long, 0.4–0.8 cm wide, dull, green for ca 8 nodes then glossy. Lamina, midrib and margin are sparsely warty and may feel slightly rough when fresh.
Flowering Time

Flowering time unknown.

Eucalyptus mimica is a mallet species endemic to Western Australia, found only in the area immediately south of Newdegate in the southern wheatbelt. It is smooth-barked with a crown of linear to narrowly elliptical, green, glossy leaves with little visible venation and numerous oil glands.

Eucalyptus mimica is a somewhat atypical species in Eucalyptus subgenus Symphyomyrtus section Bisectae subsection Glandulosae because the outer operculum of the buds does not shed early leaving an operculum scar (see description above); however, the cotyledons are bisected, branchlets have oil glands in the pith and adult leaves have a glazed surface, all of which place it firmly in subsection Glandulosae. E. mimica belongs to a subgroup further characterised by having buds with erect stamens, series Erectae, and is distinguished from most other species in this group by the buds and fruit that are square in cross-section but not winged. E. mimica differs from its close relative E. steedmanii by having smaller, unwinged buds and fruit. 

The restricted occurrence, square buds and fruit which are always in clusters of three, and unusual outer operculum character mean that E. mimica is unlikely to be confused with any other species.

There are two subspecies:

E. mimica subsp. mimica
Distinguished by the outer operculum forming separate sepals that are ultimately deciduous, and the apparently saline habitat. Found south-east of Newdegate.

E. mimica subsp. continens 
The outer operculum does not form separate sepals but remains unshed on the bud until flowering. Occurs on low lying country immediately south of Newdegate.
Origin of Name
Eucalyptus mimica: from Latin mimicus, mimicking, referring to the similarity with E. steedmanii.
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