Eucalyptus prominula

Bucketty stringybark

Eucalyptus | Eucalyptus | Capillulus | Pachyphloius

Eucalyptus prominula L.A.S.Johnson & K.D.Hill, Telopea 4: 248 (1991).

T: New South Wales: Central Coast, 1 mile [1.6 km] N of Bucketty on Old North Road, 12 May 1960, L.A.S.Johnson s.n.; holo: NSW.

Tree to 20 m tall. Forming a lignotuber.
Bark rough to small branches, stringy, grey and grey-brown.
Branchlets not glaucous; lacking oil glands in the pith.
Juvenile growth (coppice or field seedlings to 50 cm): stems round in cross-section, densely stellate hairy throughout; juvenile leaves sessile to shortly petiolate (petioles 0.1–0.3 cm), opposite for few nodes soon becoming alternate, ovate to broadly so, 3–7.5 cm long, 2–4 cm wide (ratio length: width 1.5–2), bases appear stem-clasping if petiole very short but more commonly rounded or sometimes nearly truncate, margin entire, apex pointed, discolorous, darker green on upper side, setose only on petiole, margin and main veins underneath. At 50 cm tall new growth tips conspicuously stellate hairy.
Adult leaves alternate, petiole 1.3–2.5 cm long; blade broadly lanceolate to lanceolate or falcate, 7–15 cm long, 1.4–3.2 cm wide, base tapering or oblique, concolorous, glossy green to greyish green, side-veins acute, sparsely reticulate, intramarginal vein parallel to margin, oil glands irregular, island.
Inflorescence axillary unbranched, peduncles 1.5–2 cm long, thick and angular, buds 9 to ?15 per umbel, pedicellate (pedicels angular 0.2–0.4 cm long). Mature buds buds fusiform or more or less ovate, 0.7–0.9 cm long, 0.3–0.4 cm wide, longitudinally angled, yellowish, smooth, scar absent, operculum elongated conical (longer than hypanthium), stamens irregularly flexed, anthers reniform to cordate, versatile, dorsifixed, dehiscing by confluent slits, style long, stigma blunt or tapered, locules 4, the placentae each with 2 vertical ovule rows. Flowers white.
Fruit pedicellate (pedicels 0.2–0.4 cm long), flattened-hemispherical, 0.6–0.7 cm long, 0.7–1 cm wide, disc level to raised-convex, valves 4, near rim level with tips only protruding.
Seeds dark brown to blackish, 1.5–2.5 mm long, pyramidal or obliquely pyramidal, dorsal surface smooth, hilum terminal.

Cultivated seedlings (measured at ca node 10): cotyledons reniform; not grown.

Flowering time not recorded.

A stringybark tree endemic to New South Wales where found from north of Wisemans Ferry to Bucketty and Broke, and west as far as Putty and the Culoul Range; on poor shallow soils on sandstone or shale slopes and ridges. It has rough bark throughout and a green to grey-green crown of large thickish leaves. The angular buds and the fruit are always pedicellate; juvenile growth is stellate hairy with consistently shortly petiolate short broad ovate leaves with mostly rounded leaf-bases.

Eucalyptus prominula has been confused with other stringybark species, particularly E. agglomerata and E. capitellata, both of which differ in having sessile buds and clusters of crowded laterally deformed fruit. E. agglomerata occurs in taller forests on slightly moister sites while E. capitellata occurs closer to the coast on dry sandstone sites. Two other stringybark species, E. sparsifolia and E. expressa, grow within the geographic range of E. prominula. E. sparsifolia grows with E. prominula in some areas but has very narrow green crown leaves and small buds and fruit. E. expressa occurs on sheltered sites and is easily distinguished by its taller habit, small fusiform buds, smaller fruit with very prominently exserted valves, thinner textured crown leaves with marginal lenticels and prominently petiolate ovate juvenile leaves.

The stringybark Eucalyptus bensonii occurs in the south-west of Wollemi National Park, to the west of the distribution of E. prominula and differs in its stunted habit, sessile buds with more rounded-conic operculum and sessile crowded fruit.

In earlier editions of EUCLID Eucalyptus prominula was included as an outlier of the Northern Tableland species E. youmanii but that was an error although the two species seem closely related. E. youmanii has sessile or pedicellate angular diamond-shaped buds consistently in clusters of 7 on more flattened peduncles; the narrower buds of E. prominula are always pedicellate, have a longer operculum, and are borne in clusters of 9 to ?15. E. youmanii has slightly larger more globose fruit with a conspicuously broad raised disc. The juvenile leaves on field coppice of E. youmanii have longer petioles and the leaf blade tends to taper basally, unlike those of E. prominula which are very rounded basally.

MORE ABOUT STRINGYBARKS

Eucalyptus prominula: from the Latin prominulus, meaning projecting only slightly, a reference to the valve-tips being scarcely exserted.