Key to the species of Calea sect. Calea from Brasil

1. Capitula radiate..................................................................................................................................................................................2.

- Capitula discoid .................................................................................................................................................................................6.

2. Capitulum solitary or capitula arranged in pairs ...............................................................................................................................3.

- Capitula arranged in capitulescences with three or more capitula ....................................................................................................4.

3. Involucre 3-seriate, 7.5–10 mm long, receptacle epaleaceous; ray florets 5–7, disc florets ca. 15; pappus scales 0.8 mm long ........ .......................................................................................................................................................................................... C. caleoides

- Involucre 6-seriate, 12.2–12.7 mm long, receptacle holopaleaceous; ray florets 8–10, disc florets 30–40; pappus scales 1.1–4.3 mm long..................................................................................................................................................................................... C. repanda

4. Ray florets 11–12; pappus scales ca. 15 ........................................................................................................................ C. lucidivenia

- Ray florets 2–10; pappus scales 25–43 .............................................................................................................................................5.

5. Leaf margins pinnatifid; capitula sparsely arranged...................................................................................................... C. pinnatifida

- Leaf margins serrate; capitula densely arranged ................................................................................................................. C. serrata

6. Phyllaries foliaceous, longer than the involucre................................................................................................................................7.

- Phyllaries foliaceous, of the same length or shorter than the involucre............................................................................................8.

7. Ray florets 12–25 .................................................................................................................................................................... C. lutea

- Ray florets 4–5 .................................................................................................................................................................. C. papposa

8. Receptacle epaleaceous ............................................................................................................................................... C. gentianoides

- Receptacle oligopaleaceous or holopaleaceous.................................................................................................................................9.

9. Involucre 4-seriate; pappus scales 1.9–2.3 mm long........................................................................................................ C. divergens

- Involucre 5–8-seriate; pappus scales 2.7–5.5 mm long...................................................................................................................10.

10. Involucre 5-seriate...........................................................................................................................................................................11.

- Involucre 7–8-seriate .......................................................................................................................................................................12.

11. Involucre 3.5–5.2 mm long; receptacle oligopaleaceous, paleae 2–4; disc florets 7–9; cypselae 2.7–3 mm long .............................. ................................................................................................................................................................................. C. diamantinensis

- Involucre 6.7–8.4 mm long; receptacle holopaleaceous, paleae 20–30; disc florets 20–30; cypselae 2–2.5 mm long ....................... ............................................................................................................................................................................................... C. oliveri

12. Leaf blade glabrous; pappus scales 15 ............................................................................................................................ C. abelioides

- Leaf blade pilose; pappus scales 16–25...........................................................................................................................................13.

13. Petiole 0.5–1.5 mm long, leaf surface abaxially pubescent ......................................................................................... C. solidaginea

- Petiole 3–7 mm long, leaf surface abaxially tomentose............................................................................................... C. lantanoides