1	"Capsules glabrous"	2
1	"Capsules with hairs"	50
2	"Dorsal faces of seeds smooth, without ornamentation or surface irregularities; seeds tetragonous, trigonal, biconvex or suborbicular in transverse section"	3
2	"Dorsal faces of seeds sculptured or variously ornamented sometimes only obscurely so or if smooth then seed tetraquetrous in transverse section"	8
3	"Involucral glands, sessile, pressed flat against the outer surface of the involucre; gland appendages absent; involucral lobes oblong to obovate, deeply laciniate distally, > 1 mm long"	"Euphorbia clementii"
3	"Involucral glands stipitate, spreading; gland appendages usually present sometimes inconspicuous; involucral lobes triangular to subulate, mostly < 1 mm long"	4
4	"Seeds biconvex in transverse section"	"Euphorbia biconvexa"
4	"Seeds trigonous or suborbicular or tetragonous in transverse section"	5
5	"Capsules > 3 mm long; stipules > 2 mm long"	"Euphorbia litticola"
5	"Capsules < 3 mm long; stipules < 2 mm long"	6
6	"Leaf blades < 5 mm wide; styles entire or scarcely divided distally"	"Euphorbia psilosperma"
6	"Leaf blades > 5 mm wide or if less then styles bifid for one third or more of their length"	7
7	"Seeds suborbicular in transverse section; plants most commonly growing on clay soils"	"Euphorbia coghlanii"
7	"Seeds trigonous in transverse section; plants most commonly growing on sandy soils"	"Euphorbia trigonosperma"
8	"Dorsal and ventral surfaces of seeds with 4–6 transverse grooves or foveate to reticulate-foveate"	9
8	"Dorsal and ventral surfaces of seeds smooth, or faintly or distinctly transversely or irregularly ridged"	10
9	"Dorsal and ventral surfaces of seeds with 4–6 transverse grooves"	"Euphorbia armstrongiana var. distans"
9	"Dorsal and ventral surfaces of seeds foveate to reticulate-foveate"	"Euphorbia wheeleri"
10	"Seeds > 1.9 mm long, > 1.5 mm wide"	"Euphorbia kimberleyensis"
10	"Seeds < 1.9 mm long or if > 1.9 mm then < 1.5 mm wide"	11
11	"Cyathia in lax to congested leafy terminal dichasia or monochasia or in congested axillary bracteose dichasia"	12
11	"Cyathia solitary at the nodes, sometimes clustered on short leafy lateral branches"	15
12	"Capsules minutely papillose; gland appendages absent or if present < 0.1 mm long"	"Euphorbia vicina"
12	"Capsules smooth; gland appendages present, > 0.1 mm long"	13
13	"Stipules broad-triangular, 0.3–0.6 mm long, with margins lacerate, teeth gland-tipped"	"Euphorbia hyssopifolia"
13	"Stipules deeply bipartite, lobes subulate to narrow-triangular, 0.6–2 mm long, with margins entire or laciniate, sometimes with teeth gland-tipped"	14
14	"Cyathia in terminal lax dichasial or monochasial cymes, usually above subtending leaves"	"Euphorbia mitchelliana"
14	"Cyathia in congested dichasial cymes, mostly axillary on short lateral branchlets, usually shorter than subtending leaf"	"Euphorbia bifida"
15	"Stems hairy, sometimes only proximally"	16
15	"Stems glabrous"	19
16	"Involucral glands cupuliform, deeply sunken in centre with distinct rim"	17
16	"Involucral glands patelliform, either ± planar or concave with tangential trough but not deeply sunken in centre with distinct rim"	18
17	"Capsules distinctly wider than long, 1.5–1.8 × 2–2.7, deeply 3-lobulate"	"Euphorbia schultzii"
17	"Capsules only slightly wider than long, 1.4–2.1 × 1.5–2, shallowly 3-lobulate"	"Euphorbia hassallii"
18	"Gland appendages conspicuous, > 0.3 mm long; staminate flowers per cyathia mostly 10 or more; stems sparsely to densely hairy with appressed to spreading hairs  <0.5 mm long"	"Euphorbia maconochieana"
18	"Gland appendages inconspicuous and < 0.3 mm long or absent; staminate flowers per cyathia < 10; stems sparsely hairy with spreading hairs > 0.5 mm long"	"Euphorbia inappendiculata"
19	"Seeds faces ± smooth"	20
19	"Seeds faces sculptured or variously ornamented sometimes only obscurely so"	22
20	"Capsules widest below the middle; seeds <1 mm long"	"Euphorbia cinerea"
20	"Capsules widest at the middle or if widest below middle then seeds >1 mm long"	21
21	"Capsules distinctly longer than wide"	"Euphorbia ferdinandi var. ferdinandi"
21	"Capsules more or less as long as wide"	"Euphorbia multifaria"
22	"Capsules >1.2 times wide as long, transversely broad-elliptic in lateral view, deeply 3-lobulate; involucral glands cupuliform; gland appendages entire"	"Euphorbia schultzii"
22	"Capsules <1.2 times wide as long, or if >1.2 times as long as wide then either capsules broad-ovate to depressed ovate in lateral view and shallowly 3-lobulate or involucral glands patelliform or gland appendages toothed or deeply irregularly lobed"	23
23	"Seeds <1 mm long"	24
23	"Seeds >1 mm long"	26
24	"Styles entire"	"Euphorbia cinerea"
24	"Styles bifid for 1/3–1/2 of their length"	25
25	"Dorsal faces of seed concave, with prominent irregular rounded ridges; gland appendages entire, crenulate or shallowly irregularly lobed"	"Euphorbia philochalix"
25	"Dorsal faces of seed planar, with faint rounded, irregularly ridges; gland appendages toothed or deeply lobed"	"Euphorbia sharkoensis"
26	"Involucral glands patelliform, flat or concave with tangential trough, rim of gland not thickened"	27
26	"Involucral glands cupuliform, deeply sunken in the centre, usually with thickened rim"	35
27	"Stipules on at least one side of stem triangular to broadly triangular, with toothed margins but not deeply bipartite"	"Euphorbia dallachyana"
27	"Stipules deeply bipartite, with lobes subulate to triangular"	28
28	"Gland appendages <0.2 mm long or absent"	29
28	"Gland appendages >0.2 mm long"	34
29	"Capsules >2 mm long; stems ascending to erect, rarely prostrate; staminate flowers per cyathium 10–30; styles 0.5–0.9 mm long"	"Euphorbia myrtoides"
29	"Capsules <2 mm long; stems prostrate rarely erect; staminate flowers per cyathium 5–15; styles 0.2–0.6 mm long"	30
30	"Styles entire, 0.2–0.3 mm long"	"Euphorbia multifaria"
30	"Styles bifid for 1/3–1/2 their length, 0.3–0.6 mm long"	31
31	"Leaves minutely papillose (visible at 40× mag.)"	"Euphorbia inappendiculata"
31	"Leaves ± smooth"	32
32	"Stipules >1 mm long; involucral glands up to 0.1 mm long"	"Euphorbia inappendiculata"
32	"Stipules <1 mm long; involucral glands >0.1 mm long"	33
33	"Dorsal faces of seeds undulate or obscurely ridged; seeds 1–1.5 mm long, growing in sandy soils on rocky limestone foreshores and coastal sand dunes north-western Western Australia"	"Euphorbia sharkoensis"
33	"Dorsal faces of seeds distinctly ridged; seeds 1.5–1.7 mm long; growing on inland sand dunes in the Great Victoria Desert"	"Euphorbia victoriensis"
34	"Staminate flowers <10 per cyathia or if 10 then capsules <2 mm long; seeds <1.5 mm long"	"Euphorbia sharkoensis"
34	"Staminate flowers >10 per cyathia or if 10 then capsules >2 mm long; seeds >1.5 mm long"	"Euphorbia myrtoides"
35	"Stipules on at least one side of stem broadly triangular, not deeply bipartite; hypogynous disc mostly laciniate; stems prostrate, rarely erect or ascending"	"Euphorbia dallachyana"
35	"Stipules subulate to triangular, deeply bipartite; hypogynous disc mostly entire; stems ascending to erect or prostrate"	36
36	"Gland appendages >0.1 mm long"	37
36	"Gland appendages <0.1 mm long or absent"	42
37	"Capsules broadest towards the base"	38
37	"Capsules broadest towards the equator"	40
38	"Dorsal faces of seeds with medial irregular longitudinal ridge"	"Euphorbia porcata"
38	"Dorsal faces of seeds irregularly ridged but without medial longitudinal ridge"	39
39	"Dorsal faces of seed with low faint irregular ridges; plants usually robust herbaceous perennials to 30 cm tall; stems erect rarely prostrate; gland appendages 0.2–0.4 mm long"	"Euphorbia albrechtii"
39	"Dorsal faces of seeds with prominent irregular ridges; plants slender herbaceous perennials to 15 cm tall; stems prostrate rarely ascending; gland appendages 0.1–0.3 mm long"	"Euphorbia philochalix"
40	"Leaf blades >3 times as long as wide; seeds 0.8–1.3 mm long, distinctly or obscurely irregularly ridged; styles scarcely bifid to divided c. 1/3 of their length; involucral glands 0.3–0.5 mm wide"	"Euphorbia hassallii"
40	"Leaf blades <3 times as long as wide or if up to 3.3 times as long as wide then either seeds >1.3 mm long and obscurely irregularly ridged, or styles entire, or involucral glands <0.2 mm wide"	41
41	"Dorsal faces of seeds irregularly ridged"	"Euphorbia inappendiculata"
41	"Dorsal faces of seeds with a medial longitudinal ridge"	"Euphorbia porcata"
42	"Dorsal surface of seeds with 6–9 transverse ridges; exotesta of uneven thickness, always thicker on ridges"	"Euphorbia fitzroyensis"
42	"Dorsal faces of seeds with irregular ridges, or tuberculate or if transversely ridged then with 3–6 ridges on dorsal faces of seed; exotesta ± of even thickness over seed surface"	43
43	"Styles entire or scarcely notched at the apex, 0.2–0.3 mm long; dorsal surface of seeds distinctly transversely or irregularly ridged; capsules broadest towards the middle"	44
43	"Styles bifid for 1/3–2/3 of their length or if entire or scarcely notched at the apex then either dorsal faces of seeds obscurely undulate or capsules broadest towards the base; styles 0.2–0.6 mm"	46
44	"Leaves <6 mm long; stems not longitudinally ribbed; dorsal face of seeds irregularly ridged; exotesta of uneven thickness over seed surface (thicker on ridges)"	"Euphorbia multifaria"
44	"Leaves >6 mm long or if <6 mm long then stems longitudinally ribbed, dorsal faces of seeds with 3–6 transverse ridges and exotesta of ± even thickness over surface"	45
45	"Leaves rounded at apex; dorsal faces of seeds with 3–6 transverse ridges"	"Euphorbia drummondii"
45	"Leaves acute to obtuse at apex, or if rounded then dorsal faces of seeds with irregular ridges"	"Euphorbia hassallii"
46	"Stipules subulate, 1–1.7 mm long; involucral glands poorly formed up to 0.1 mm long and 0.1–0.2 mm wide"	"Euphorbia inappendiculata"
46	"Stipules narrow-triangular to triangular or if subulate then <1.1 mm long; involucral glands well formed, 0.1–0.2 mm long by 0.1–0.7 mm wide"	47
47	"Largest leaves >8 mm long, mostly >3 times as long as wide"	"Euphorbia hassallii"
47	"Largest leaves <8 mm long, <3 times as long as wide"	48
48	"Dorsal faces of seeds with an irregularly medial longitudinal ridge"	"Euphorbia porcata"
48	"Dorsal faces of seeds undulate, faintly irregularly ridged or with irregular wart-like protuberances"	49
49	"Dorsal faces of seeds with irregular wart-like protuberances"	"Euphorbia verrucitesta"
49	"Dorsal faces of seeds undulate or only faintly irregularly ridged"	"Euphorbia multifaria"
50	"Indumentum on stems consisting of two hairs types; white short more or less appressed crispate hairs to 0.5 mm long and yellow spreading segmented hairs to 1.5 mm long; cyathia in dense capitate, terminal or axillary cymose clusters"	"Euphorbia hirta"
50	"Indumentum on stems consisting of one hair type or absent; cyathia solitary, clustered on congested lateral branchlets, or in lax to congested leafy terminal and axillary dichasial cymes"	51
51	"Capsules with hairs unevenly distributed over surface either restricted to keels or towards the base of the capsule"	52
51	"Capsules with hairs evenly distributed over surface"	57
52	"Seeds >1.9 mm long"	"Euphorbia kimberleyensis"
52	"Seeds <1.9 mm long"	53
53	"Capsules with hairs mostly towards the base; hairs more than 0.8 mm long"	"Euphorbia vaccaria"
53	"Capsules with hairs restricted to keels; hairs mostly less than 0.8 mm long"	54
54	"Capsules <1.5 mm across; involucral gland appendages <0.2 mm long; staminate flowers per cyathium <10; stems prostrate or weakly ascending, glabrous on lower surface"	"Euphorbia prostrata"
54	"Capsules >1.5 mm across or if less then involucral gland appendages >0.2 mm long, staminate flowers per cyathium >10 and stems erect or if prostrate or ascending then evenly hairy"	55
55	"Capsules distinctly wider than long, 2–3 mm across, deeply 3-lobulate"	"Euphorbia schultzii"
55	"Capsules ± as long as wide, 1.5–2.3 mm across, shallowly 3-lobulate"	56
56	"Leaf blades 7–70 mm long, glabrous or with a few scattered hairs, with margins entire or finely serrulate; seeds tetragonous or trigonous in transverse section; seed surfaces with 3–7 prominent narrow rounded transverse ridges"	"Euphorbia mitchelliana"
56	"Leaf blades 3–7 mm long, sparsely to densely hairy, with margins often coarsely serrate; seeds tetraquetrous in transverse section; seed surfaces with low faint to distinct irregular ridges"	"Euphorbia centralis"
57	"Seeds >1.9 mm long"	"Euphorbia schizolepis"
57	"Seeds <1.9 mm long"	58
58	"Styles entire or scarcely notched"	59
58	"Styles bifid for at least 1/3 of their length"	60
59	"Involucral glands patelliform, either ± planar or shallowly concave; gland appendages deeply laciniate with narrow attenuate teeth, >0.4 mm long"	"Euphorbia centralis"
59	"Involucral glands cupuliform, deeply sunken in centre with distinct thickened rim; gland appendages entire or shallowly irregularly lobed or bluntly toothed, up to 0.6 mm long"	"Euphorbia schultzii"
60	"Pedicel of mature capsules <1 mm long; capsules not completely exserted from involucre at maturity causing the involucre to split"	"Euphorbia thymifolia"
60	"Pedicel of mature capsules >1 mm long; capsules completely exserted from involucre at maturity"	61
61	"Cyathia solitary at nodes or in congested short lateral leafy branches (leaves on lateral branches usually smaller in size than main branches but not reduced to bracts)"	62
61	"Cyathia in lax terminal dichasia or monochasia or in congested axillary bracteose dichasia"	67
62	"Hairs on capsules appressed; seeds <1 mm long; annual herbs to 10 cm high with prostrate or weakly ascending stems; leaf blades green often with elongate purple spot centrally; stipules 1–2.3 mm long; hairs on stem up to 0.8 mm long"	"Euphorbia maculata"
62	"Hairs on capsules spreading or if appressed then either seeds >1 mm long or herbaceous perennials with ascending to erect stems or leaf blades yellowish green or stipules <1 mm long or hairs on stems to 0.2 mm long"	63
63	"Capsules depressed ovate or transversely elliptic in lateral view, distinctly wider than long, acutely keeled; leaf blades ovate, oblong or obovate, >1.5 times longer than wide"	"Euphorbia schultzii"
63	"Capsules broad-ovate to very broad-ovate or broad-elliptic in lateral view, as long as wide or if depressed ovate then only slightly wider than long, obtusely keeled and leaf blades elliptic to broad elliptic and <1.5 times longer than wide"	64
64	"Gland appendages deeply laciniate with narrow attenuate teeth"	"Euphorbia centralis"
64	"Gland appendages entire, bluntly lobed or acutely toothed"	65
65	"Gland appendages white rarely pale pink, entire; stems prostrate; capsules conspicuously papillose and only sparsely hairy with hairs up to 0.1 mm long; leaf blades strongly asymmetric at base"	"Euphorbia maconochieana"
65	"Gland appendages red, yellow or if white or pink then irregularly lobed or toothed; stems prostrate, ascending to erect; capsules smooth or if papillose then only minutely so and sparsely to densely hairy with hairs 0.1–0.5 mm long; leaf blades weakly to strongly asymmetric at base"	66
66	"Cyathia mostly unisexual; hairs on stems <0.2 mm long; involucral glands ± flat, 0.3–0.5 mm long by 0.4–0.8 mm wide"	"Euphorbia careyi"
66	"Cyathia bisexual; hairs on stems >0.2 mm long or if equal to or shorter then involucral glands concave or with shallow central pit, <0.3 mm long and <0.4 mm wide"	"Euphorbia australis"
67	"Capsules minutely papillose; gland appendages absent or if present then <0.1 mm long"	"Euphorbia vicina"
67	"Capsules smooth; gland appendages present, >0.1 mm long"	68
68	"Cyathia in axillary or terminal congested dichasial cymes"	"Euphorbia bifida"
68	"Cyathia in terminal lax dichasial or monochasial cymes"	"Euphorbia mitchelliana"