1	"Flowers 5-merous (subg. Pentacalothamnus)"	2
1	"Flowers 4-merous (subg. Calothamnus)"	22
2	"Hypanthium at anthesis not immersed in rachis"	3
2	"Hypanthium at anthesis immersed in rachis"	21
3	"Leaves flat, at least 2 mm wide"	4
3	"Leaves terete, if flattened then less than 2 mm wide"	5
4	"Hypanthium glabrous except villous band at base; stems glabrous"	"Calothamnus glaber"
4	"Hypanthium villous; stems hirsute"	"Calothamnus blepharospermus"
5	"Leaves less than 3 cm long"	6
5	"All or at least some leaves more than 3 cm long"	11
6	"Fruit more than 10 mm long"	7
6	"Fruit 10 mm long or less"	8
7	"Fruit 10–12 mm long, commonly corky; seed papillose on angles; leaves abruptly narrowed to apex (Tamala Stn to Northampton)"	"Calothamnus oldfieldii"
7	"Fruit 13–17 mm long, smooth; seed not papillose (East Mt Barren)"	"Calothamnus macrocarpus"
8	"Hypanthium appressed-pubescent"	9
8	"Hypanthium villous"	10
9	"Leaves 0.5–0.8 mm wide, pilose towards base, otherwise glabrous; petals 4–6 mm long; fruit 4–5 mm long; seeds 0.7–0.8 mm long (Marchagee to Corrigin and Pingelly)"	"Calothamnus brevifolius"
9	"Leaves 0.8–1 mm wide, hirsute when young, glabrescent; petals 6.5–7 mm long; fruit 5–6 mm long; seeds 1.5–2 mm long (Watheroo to Perth)"	"Calothamnus accedens"
10	"Stems hirsute; fruit 4–6 mm long; all sepals falling after anthesis (Arrowsmith to Mundijong)"	"Calothamnus hirsutus"
10	"Stems glabrous, or pubescent around leaf bases; fruit 8–10 mm long; 1 or 2 sepals persistent (C. Riche to Mt Ragged)"	"Calothamnus villosus"
11	"Hypanthium villous"	"Calothamnus chrysanthereus"
11	"Hypanthium hirsute, silky, pubescent, tomentose or glabrous"	12
12	"Staminal bundles 35–38 mm long; fruit 12–14 mm long"	"Calothamnus cupularis"
12	"Staminal bundles 20–30 mm long; fruit usually less than 12 mm long (to 13 mm in C. gilesii)"	13
13	"Hypanthium glabrous or hairy at base only"	14
13	"Hypanthium hairy throughout"	17
14	"Leaves prominently pustulate (Bruce Rock to Diemals)"	"Calothamnus superbus"
14	"Leaves not pustulate"	15
15	"Two sepals persistent in fruit, enlarged; seed not papillose"	"Calothamnus gilesii"
15	"Sepals all falling after anthesis, not evident or only as small bumps, or all persistent and ± equal; seed papillose"	16
16	"Hypanthium 4–5 mm long; petals glabrous; fruit cylindrical, warted; leaves commonly 4–6 cm long (Shark Bay to Yuna)"	"Calothamnus formosus"
16	"Hypanthium 2.5–3 mm long; petals pubescent; fruit depressed-globose, with large irregular bumps or smooth; leaves 7–10 cm long (Newman to Paynes Find & Leonora, Carnarvon Ra.)"	"Calothamnus aridus"
17	"Mature leaves hairy, greyish (Exmouth to L. Macleod, Kennedy Ra.)"	"Calothamnus borealis"
17	"Mature leaves glabrous, green"	18
18	"Hypanthium 2.5–3.5 mm long (Newman to Paynes Find & Leonora, Carnarvon Ra.)"	"Calothamnus aridus"
18	"Hypanthium 4–6 mm long"	19
19	"Leaves spreading but upcurved; fruit 5–6 mm long (NE of Eneabba, Arrino)"	"Calothamnus arcuatus"
19	"Leaves erect; fruit 7–13 mm long"	20
20	"Fruit depressed-globose, usually with corky bark, the sepals falling (Eurardy Stn to Yuna)"	"Calothamnus phellosus"
20	"Fruit barrel-shaped, smooth, with 2 sepals enlarged, woody (Yuna to Hyden & Fraser Ra., Great Victoria Desert)"	"Calothamnus gilesii"
21	"Stem slender (except bud swellings), not corky; seed angles papillose"	"Calothamnus gracilis"
21	"Stem thickened, corky; seed angles smooth"	"Calothamnus gibbosus"
22	"Hypanthium at anthesis not immersed in rachis"	23
22	"Hypanthium at anthesis immersed in rachis"	34
23	"Staminal claws equal or almost so"	24
23	"Staminal claws markedly unequal"	33
24	"Leaves flat"	"Calothamnus quadrifidus"
24	"Leaves terete"	25
25	"Hypanthium glabrous"	26
25	"Hypanthium variously hairy"	27
26	"Fruit 15–22 mm long"	"Calothamnus graniticus"
26	"Fruit 6–14 mm long"	"Calothamnus quadrifidus"
27	"Fruit 4–5 mm long; leaves ± glaucous (south-eastern granite rocks)"	"Calothamnus tuberosus"
27	"Fruit more than 7 mm long; leaves not glaucous"	28
28	"Hypanthium villous"	29
28	"Hypanthium puberulous or tomentose"	30
29	"Stems hirsute; leaves recurved to spreading; staminal bundles 23–32 mm long; smaller sepals, if persistent, incurved; fruit 8–12 mm long (C. Riche to Cheyne Beach)"	"Calothamnus robustus"
29	"Stems pubescent, glabrescent; leaves erect; staminal bundles 30–37 mm long; smaller sepals curved outwards in fruit; fruit 14–17 mm long (Darling Scarp, Boyagin Rock, near Wongan Hills)"	"Calothamnus rupestris"
30	"Leaves pungent"	"Calothamnus pinifolius"
30	"Leaves obtuse or, if acute, then not pungent"	31
31	"Hypanthium 3–4 mm long"	"Calothamnus quadrifidus"
31	"Hypanthium 5–7 mm long"	32
32	"Leaves 2.5–4.5 cm long; stamens deep pink (S of Ravensthorpe)"	"Calothamnus roseus"
32	"Leaves 1.2–2.2 cm long; stamens red (Fitzgerald R. Natl Park)"	"Calothamnus validus"
33	"Upper pair of staminal claws united for all or most of their length; free filaments glabrous; stamens bright red"	"Calothamnus sanguineus"
33	"Upper pair of staminal claws free from each other; free filaments woolly; stamens dull dark red outside, creamish inside"	"Calothamnus torulosus"
34	"Upper pair of staminal claws much broader than lower pair, with 25–30 stamens per bundle (north of Perth)"	35
34	"Staminal claws ± equal in width, with 1–7 stamens per bundle (south of Perth)"	36
35	"Leaves flat; anthers hairy"	"Calothamnus pachystachyus"
35	"Leaves terete; anthers glabrous"	"Calothamnus longissimus"
36	"Leaves flat (often narrowly so in C. microcarpus)"	37
36	"Leaves terete"	38
37	"Fruit 2–2.5 mm long; leaves 2–3 mm wide, gently tapering to apex, green"	"Calothamnus microcarpus"
37	"Fruit 3–5 mm long; leaves 2–11mm wide, abruptly curved in to apex, bluish"	"Calothamnus planifolius"
38	"Leaves 1–5 cm long"	"Calothamnus lehmannii"
38	"All or most leaves more than 5 cm long"	39
39	"Staminal bundles 5–6 mm long; prostrate or decumbent shrub"	"Calothamnus schaueri"
39	"Staminal bundles more than 10 mm long; erect shrub except C. preissii"	40
40	"Prostrate or sprawling shrub; leaves commonly sinuous; lower staminal bundles with 1 or 2 stamens (York to Boyup Brook & Cranbrook)"	"Calothamnus preissii"
40	"Erect shrub; leaves ± straight to gently incurved; lower staminal bundles with 3–7 stamens"	41
41	"Leaves scabrid (Mt Roe, Mt Lindesay)"	"Calothamnus scabridus"
41	"Leaves not scabrid"	42
42	"Leaves 10–30 cm long (Perth to Augusta & Albany)"	"Calothamnus lateralis"
42	"All or most leaves less than 10 cm long"	43
43	"Hypanthium more than half free (ignore burst stem epidermis) (Stirling Ra.)"	"Calothamnus affinis"
43	"Hypanthium fully or mostly immersed"	44
44	"Leaves 3–6 cm long; staminal bundles 18–22 mm long; pistil 13–18 mm long (Woodanilling to Cranbrook & Stirling Ra.)"	"Calothamnus huegelii"
44	"Leaves 6–11 cm long; staminal bundles 25–28 mm long; pistil 20–25 mm long (Stirling Ra.)"	"Calothamnus montanus"