Botanical name

Acacia spondylophylla (erect variant) [phrase name: Acacia sp. Meentheena (S. van Leeuwen 4529)]

Description

Erect shrubs 2 m tall, with a very faint curry odour when dry. Old stems marked with annular scars (formed by the short, persistent stipule bases) where phyllodes have fallen. Branchlets with short, straight, spreading hairs. Stipules triangular, 0.5-1 mm long, wide-spreading, brown. Phyllodes arranged in whorls (6-8 (-10) phyllodes per whorl) separated by internodes that are normally shorter than the phyllodes, (4-) 5-7 mm long, 0.4-0.7 mm wide, wide-spreading, straight to shallowly incurved but often slightly recurved at the tips, flattened and finely longitudinally wrinkled when dry, invested with short, spreading hairs, bright green; sometimes obscurely 1-nerved below but nerves generally not evident although marked with fine longitudinal wrinkles that might be misinterpreted as nerves; abruptly narrowed at apex into a distinct, short, subulate, non-spiny point. Inflorescences simple; peduncles (20-) 25-30 mm long, sparsely pilose with short, soft, spreading white hairs; heads large, globular, golden (judging from dry material), 35-45-flowered. Flowers 5-merous; calyx dissected to about ½ its length, the lobes obloid to slightly spathulate; petals nerveless (not striate as in A. adoxa), glabrous or besprinkled with a few short spreading hairs. Pods and seeds unknown.

Characteristic features

Erect shrubs, with a very faint curry odour when dry. Branchlets and phyllodes invested with short, spreading hairs. Phyllodes arranged in whorls (mostly 6-8 per whorl), mostly 5-7 mm long, wide-spreading, bright green. Heads globular, large, on long peduncles (mostly 25-30 mm); petals not striate, glabrous or almost so.

Distribution and ecology

Known from only a single gathering from the Pilbara region in northwest Western Australia, in Meentheena Station Conservation Reserve, east of Marble Bar. Grows on steep scree slopes and cliff faces (eastern aspect) in skeletal red gritty soil; in low woodland of Eucalyptus leucophloia and scattered Terminalia canescens, with mixed Acacia scrub and a spinifex (Triodia sp.) ground cover.

Flowering and fruiting period

Flowering commencing in late May (and probably would extend through June and possibly into July). Pods and seeds unknown.

Affinities

This entity is most probably just a localized variant of A. spondylophylla characterized by having a more erect and slightly taller growth form. It is further distinguished from A. spondylophylla in having slightly shorter phyllodes which are more abruptly constricted at the apex into a slightly shorter mucro, and which are slightly less numerous within the whorls. Judging from dry herbarium material A. spondylophylla (erect variant) may be slightly less resinous than typical A. spondylophylla , however, this needs checking in the field. There is no typical A. spondylophylla (or A. adoxa) at the site where the erect variant occurs (S. van Leeuwen, pers. comm.).

Conservation status

There is insufficient information at present concerning this entity to justify including it on the Department of Environment and Conservation's Declared Rare and Priority Flora List.

Origin of name

The phrase name Acacia sp. Meentheena (S. van Leeuwen 4529) identifies this taxon at the W.A. Herbarium.