Cassinia, Brown, 1818

Schmidt-Lebuhn, Alexander N., Puttock, Christopher F., Davis, Robert W. & Wege, Juliet, 2018, Two new species of Ozothamnus (Asteraceae: Gnaphalieae) from Australia, Phytotaxa 336 (2), pp. 190-196 : 195

Key to the species of the Cassinia group in Western Australia and the Northern Territory

1. Capitulescence a pyramidal panicle, clearly longer than wide ......................................................................................................... 2

- Capitulescence a corymbose panicle, either ± flat-topped or at most approximately as long as wide ............................................. 4

2. Leaves 9–50 mm long; capitula pure white ............................................................................................................... Cassinia laevis

- Leaves 2.5–15.0 mm long, capitula yellowish-white, straw- to copper-coloured or reddish ........................................................... 3

3. Capitula reddish or (especially when older) straw- to copper-coloured; flowers reddish ............... Cassinia sifton Orchard (2017)

- Capitula yellowish-white; flowers cream to yellowish-white ........................................................ Cassinia arcuata Brown (1818)

4. Leaf bases decurrent on stem as distinctive green ridges ................................................................................................................. 5

- Leaves not or barely decurrent, young stems without distinctive green ridges ................................................................................ 8

5. Free part of leaf 0.5–1.5 mm long, broadly ovate to circular ................................................................. Ozothamnus lepidophyllus

- Free part of leaf (1–) 2–20 mm long, lanceolate, linear or oblanceolate ........................................................................................... 6

6. Free part of leaf erect to nearly appressed onto stem, lanceolate; leaf apex ± acute or with indistinct ± straight mucro; flowers 8–14 per capitulum ................................................................................................................................................ Ozothamnus blackallii

- Free part of leaf spreading to slightly reflexed, linear to oblanceolate; leaf apex often with reflexed mucro; flowers 6–9 per capitulum .......................................................................................................................................................................................... 7

7. Free part of leaf 5–20 mm long, linear ...................................................................................................... Ozothamnus vespertinus

- Free part of leaf 2.5–5.0 mm long, oblanceolate ...................................................................................... Ozothamnus occidentalis

8. Leaves 1.5–3.2 mm long, lanceolate, erect-appressed onto stem, base auriculate .............................................................................. .............................................................................................................. Ozothamnus cassiope (S. Moore (1899)) Anderberg (1991)

- Leaves 5–50 mm long, linear, spreading or, if somewhat erect, at least not appressed onto stem, sessile or base slightly narrowing .......................................................................................................................................................................................... 9

9. Capitula 4.5–7.0 mm long; largest involucral bracts 4.0– 5.5 mm long; flowers 9–24 per capitulum ............. Ozothamnus kempei

- Capitula 2.5–4.0 mm long; largest involucral bracts 2.0– 3.5 mm long; flowers 4–13 per capitulum ........................................... 10

10. Leaves ca. 5–21 × 0.4–0.7 mm; involucral bracts generally obovate; flowers 8–13 per capitulum .............. Ozothamnus filifolius

- Leaves ca. 9–50 × 0.5–1.5 mm; involucral bracts generally ovate; flowers 4–8 per capitulum ............................... Cassinia laevis