1	"Corolla with lower median lobe longer than the upper median lobe-pair; corolla white, pale-blue, mauve, purple, sometimes with a tinge of pink; calyx with lower lobe folded inwards over the mericarps, upper lobe significantly longer than the lower lobe [section Prostanthera]."	2
1	"Corolla with lower median lobe more or less equal to upper median lobe-pair; corolla red, orange, yellow, or dark (metallic) blue-green, rarely mauve; calyx with lower lobe remaining more or less directed outwards and forward or recurved, not enclosing the mericarps, lobes more or less equal in length [section Klanderia]"	10
2	"Branches with spines present"	3
2	"Branches not spiny"	4
3	"Calyx lobes very unequal; shrub glabrous except for a few hairs at the distal nodes; branching more or less patent and distant"	"Prostanthera nudula"
3	"Calyx lobes more or less equal in length; shrub usually hairy; branching more or less erect and relatively crowded"	"Prostanthera spinosa"
4	"Leaves terete"	"Prostanthera baxteri var. sericea"
4	"Leaves more or less flat or incurved, not terete"	5
5	"Upper calyx lobe more or less equal to lower calyx lobe; leaves 1.5–2.5 mm long"	"Prostanthera eurybioides"
5	"Upper calyx lobe much longer than the lower calyx lobe; leaves at least 4 mm long, rarely as short as 2.8 mm"	6
6	"Pedicels, bracteoles and calyces glabrous or sparsely hairy; corolla white with purple striations"	"Prostanthera striatiflora"
6	"Pedicels, bracteoles and calyces moderately to densely hairy; corolla mauve pale-violet, blue to white, purple striations may be present"	7
7	"Calyx not enlarged in fruit; leaves sparsely to densely hairy sometimes sparsely hairy adaxially, often glabrous abaxially"	"Prostanthera behriana"
7	"Calyx enlarged in fruit; leaves sparsely to densely hairy on both surfaces"	8
8	"Hairs appressed to patent, antrorse to retrorse, hence indumentum appearing scruffy"	"Prostanthera wilkieana"
8	"Hairs appressed, antrorse, hence indumentum appearing more or less smooth"	9
9	"Bracteoles 3.8–8.1 mm long, 0.4–1.1 mm wide; branches, leaves and calyces silky"	"Prostanthera sp. A"
9	"Bracteoles 0.7–3.6 mm long, 0.1–0.4 mm wide; branches silky, leaves and calyces usually not appearing silky"	"Prostanthera sp. B"
10	"Hairs irregularly branched, more or less densely covering branches, leaves, pedicels and calyx (simple hairs may also be present)."	"Prostanthera chlorantha"
10	"Hairs simple, sometimes with a few branched hairs on the calyx (KI populations of Prostanthera serpyllifolia subsp. microphylla), never on branches or leaves"	11
11	"Hairs of branches, leaves and calyces stiff, straight, appressed and antrorse"	"Prostanthera calycina"
11	"Hairs of branches, leaves and calyces more or less soft, recurved to reflexed, never appressed, frequently curled"	12
12	"Leaves ovate to narrowly ovate, sometimes suborbicular"	"Prostanthera serpyllifolia"
12	"Leaves more or less terete to linear-obovate"	13
13	"Anther appendage 1–2.5 mm long; calyx 7–12 mm long"	"Prostanthera florifera"
13	"Anther appendage to 0.3 (rarely to 0.5) mm long; calyx 5–7 mm long"	"Prostanthera aspalathoides"