| 1 (1) | Mature leaves reduced to phyllodes or not developed at all | Goto 2 |
| (2) | Leaves all bipinnate | 38 |
| 2 (1) | Phyllodes either absent (occasional twigs.rarely with a few articulate phyllodes), or continuous with the branches | 3 |
| (2) | Phyllodes present and articulate on the branches | 4 |
| 3 (1) | Phyllodes normally absent, if present then articulate on branch; flowers 3-8 per head | A. spinescens |
| (2) | Phyllodes present, continuous with branch; flowers c. 30 per head | A. continua |
| 4 (1) | Phyllodes innocuous. | 5 |
| (2) | Phyllodes pungent-pointed. | 28 |
| 5 (1) | Phyllodes to 2 cm long. | 6 |
| (2) | Phyllodes 2-12 cm long. | 16 |
| 6 (1) | Branchlets spinescent. | 7 |
| (2) | Branchlets not spinescent. | 8 |
| 7 (1) | Branchlets hairy; phyllodes n .arrow-cuneate, humped at the summit | A. acanthoclada |
| (2) | Branchlets glabrous; phyllodes broadly lanceolate, never humped | A. erinacea |
| 8 (1) | Stipules prominent and spiny | A. paradoxa |
| (2) | Stipules when present minute and not spiny. | 9 |
| 9 (1) | Shrubs prominently resinous; phyllodes viscid. | 10 |
| (2) | Shrubs not or sometimes very slightly resinous; phyllodes not viscid, 5-20 mm long. | 11 |
| 10 (1) | Phyllodes fiat, obliquely obovate, 2-5 mm long | A. rhetinocarpa |
| (2) | Phyllodes terete-compressed, 1-2 cm long | A. helmsiana |
| 11 (1) | Phyllodes ovate-oblanceolate to obovate-orbicular. | 12 |
| (2) | Phyllodes linear or oblong. | 14 |
| 12 (1) | Phyllodes grey-green, heads 20-30 flowered. | 13 |
| (2) | Phyllodes mid-green; heads 10-15-flowered; peduncles often longer than phyllodes; legumes spirally coiled | A. acinacea |
| 13 (1) | Peduncles mostly longer than phyllodes, heads 8-10 mm diam | A. spilleriana |
| (2) | Peduncles mostly shorter than phyllodes, heads about 5 mm diam | A. brachybotrya |
| 14 (1) | Branchlets pubescent, almost terete; phyllodes with the vein ~ close to the lower margin | A. lineata |
| (2) | Branchlets glabrous, angular. | 15 |
| 15 (1) | Phyllodes erect, imbricate; apex almost truncate except for an oblique mucro | A. imbricata |
| (2) | Phyllodes spreading-erect, not imbricate, apex obtuse | A. triquetra |
| 16 (1) | Branchlets acutely angular, often compressed and winged. | 17 |
| (2) | Branchlets angular or striate, becoming almost terete, never flattened or winged. | 19 |
| 17 (1) | Phyllodes with obviously reticulate lateral veins; peduncles stout, solitary; heads c. 40-flowered; seeds transversely placed in the legume. | 18 |
| (2) | Phyllodes without reticulate lateral veins; peduncles slender, 2-4 (rarely 1) per axil; heads 12-20-flowered; seeds longitudinally placed in the legume | A. triquetra |
| 18 (1) | Phyllodes often glaucous, broadly ovate, 10-35 mm broad, up to twice as long as broad | A. anceps var. anceps |
| (2) | Phyllodes never glaucous, linear-oblong, oblanceolate, 5-13 mm broad, 5-12 times longer than broad | A. anceps var. angustifolia |
| 19 (1) | Branchlets and phyllodes pubescent or becoming glabrous when mature. | 20 |
| (2) | Branchlets and phyllodes glabrous (young phyllodes minutely pubescent in A. microcarpa). | 22 |
| 20 (1) | Phyllodes always hairy, golden pubescent when young, silky-silvery with more or less appressed hairs when mature, flower-heads mostly shorter than phyllode, longer if common peduncle well developed | A. argyrophylla |
| (2) | Phyllodes silky grey hairy when young, becoming glabrous with age. | 21 |
| 21 (1) | Peduncle mostly shorter than phyllode, heads about 5 mm diam | A. brachybotrya |
| (2) | Peduncles mostly longer than leaf, heads 8-10 mm diam | A. spilleriana |
| 22 (1) | Phyllodes terete or if flattened then not exceeding 5 mm broad; apex always uncinate. | 23 |
| (2) | Phyllodes distinctly flattened, 5-15 mm broad; apex sometimes mucronate, never distinctly uncinate. | 25 |
| 23 (1) | Apex always acute or acuminate. | 24 |
| (2) | Apex always blunt with two glands at summit, phyllodes often slightly upcurved | A. praemorsa |
| 24 (1) | Peduncle in axillary racemes commonly 1-4 mm long with 2-4 peduncles rarely greater, rarely solitary | A. calamifolia |
| (2) | Peduncles almost always solitary | A. nematophylla |
| 25 (1) | Branchlets and young phyllodes viscid; phyllodes punctate, apex acute, with up to 4 glands along the upper margin | A. dodonaeifolia |
| (2) | Branchlets and phyllodes not viscid, or phyllodes not punctate, apex obtuse, only 1 gland along the upper margin. | 26 |
| 26 (1) | Phyllodes 5-12 cm long, apex mostly obtuse, mid-vein prominent and many fine lateral veins, peduncles < 5 mm | A. stricta |
| (2) | Phyllodes to 5 cm long, apex acute or obtuse, mid-vein often obscure, peduncles > 5 mm. | 27 |
| 27 (1) | Phyllode apex obtuse, phyllodes straight or with slight upward cur~e, young tips + glabrous | A. microcarpa |
| (2) | Phyllode apex acute, phyllodes slightly recurved, young tips densely pubescent (later glabrous) | A. halliana |
| 28 (1) | Stipules prominent and spiny. | 29 |
| (2) | Stipules when present small and not spiny. | 30 |
| 29 (1) | Phyllodes flat, glabrous, rhomboid-orbicular, 1-2 cm long | A. strongylophylla |
| (2) | Phyllodes terete, minutely pubescent, 3-6 cm long | A. pickardii |
| 30 (1) | Phyllodes humped on the upper margin. | 31 |
| (2) | Phyllodes not humped on the upper margin. | 32 |
| 31 (1) | 1 prominent vein parallel to and near the lower margin; heads whitish-yellow, 20-30-flowered; legumes straight or curved | A. gunnii |
| (2) | 1 prominent oblique vein with 2-4 rather obscure veins arising from near the base; heads golden-yellow, 8-15-flowered; legumes spirally coiled | A. pravifolia |
| 32 (1) | Phyllodes flat, obliquely ovate-orbicular or obovate, 5-15 mm broad, up to twice as long as broad | A. merrallii |
| (2) | Phyllodes flat or angular, linear-subulate or linear-lanceolate or narrow-elliptic, 1-5 mm broad, more than twice as long as broad. | 33 |
| 33 (1) | Branchlets resinous; phyllodes viscid (at least when young), 1-2.5 cm long. | 34 |
| (2) | Branchlets not resinous; phyllodes not viscid, 2-6 cm long. | 35 |
| 34 (1) | Heads c. 20-flowered, creamy-yellow; phyllodes spreading horizontally, broadest at or near the base, viscid | A. rupicola |
| (2) | Heads 50-60-flowered, mid-yellow; phyllodes erect or spreading, broadest near the centre, slightly viscid | A. maitlandii |
| 35 (1) | Phyllodes pubescent | A. carnei |
| (2) | Phyllodes glabrous (at least with age). | 36 |
| 36 (1) | Phyllodes usually clustered in groups 2-5, heads c. 50flowered | A. tetragonophylla |
| (2) | Phyllodes scattered, not clustered, heads less than c. 20 flowered. | 37 |
| 37 (1) | Heads creamy yellow; phyllodes at right angles to branch, apex tapered | A. genistifolia |
| (2) | Heads golden yellow; phyllodes ascending, apex abruptly pungent | A. mutabilis |
| 38 (1) | Inflorescences simple, solitary or 2-3 together | 39 |
| (2) | Inflorescence racemose or paniculate | 40 |
| 39 (1) | Stipules prominent, spiny; pinnules 10-21 pairs | A. farnesiana |
| (2) | Stipules minute, not spiny, pinnules 2-7 pairs | A. mitchellii |
| 40 (1) | Branches prominently angled with wing-like ridges | A. decurrens |
| (2) | Branches angled or striate but not winged | 41 |
| 41 (1) | Leaves with 2-6 pairs of pinnae | A. baileyana |
| (2) | Leaves with 10-26 pairs of pinnae | 42 |
| 42 (1) | Leaf rhachis with a gland at the junction of each pinna pair and with additional glands between the pinna pairs | A. mearnsii |
| (2) | Leaf rhachis with a gland at the junction of each pinna pair, without additional glands between | A. dealbata |