TAXONOMIC KEY TO INFRAGENERIC TAXA AND SPECIES OF NEUROLAENA

1. Ratio of paleae-disc corolla length greater than 1 ......................................................................................... N. sect. Neurolaena ... 2

- Ratio of paleae-disc corolla length equal to or less than 1 ............................................................................ N. sect. Brevipaleae ... 8

2. Involucre cylindrical, paleae 4.9–6.5 mm long ............................................................................................... N. ser. Neurolaena ... 3

- Involucre campanulate, paleae 7–10 mm long.......................................................................................... N. ser. Macrocephalae ... 6

3. Cypselae glandular-punctate............................................................................................................................................... N. balsana

- Cypselae eglandular............................................................................................................................................................................4

4. Involucre 7.5–10 mm long ............................................................................................................................................. N. intermedia

- Involucre 2.75–7 mm long .................................................................................................................................................................5

5. Abaxial leaf surface eglandular, leaf blade entire; phyllaries glabrous; pappus bristles 50–60........................................... N. lamina

- Abaxial leaf surface glandular-punctate, leaf blade bilobed; phyllaries pilose; pappus bristles 30–40................................ N. lobata

6. Abaxial leaf surface eglandular .......................................................................................................................................... N. schippii

- Abaxial leaf surface glandular-punctate .............................................................................................................................................7

7. Paleae 7–8 mm long; disc floret tube 1.8–2 mm long......................................................................................................... N. wendtii

- Paleae 8.5–9.5 mm long; disc floret tube 2.4–3 mm long........................................................................................ N. macrocephala

8. Heads discoid; paleae 5.5–7.4 mm long................................................................................................................. N. ser. Eradiatae 9

- Heads radiate; paleae 3.3–5.45 mm long............................................................................................................... N. ser. Radiatae 11

9. Shrubs 1–1.5 m tall; involucre 9–9.5 × 14–14.5 mm .............................................................................................. N. jannaweissana

- Shrubs 2–8 m tall; involucre 5–8 × 4.6–8 mm .................................................................................................................................10

10. Cypselae glabrous............................................................................................................................................................ N. venturana

- Cypselae pilose............................................................................................................................................................ N. macrophylla

11. Venation camptodromous; disc florets per capitulum 25–30, corollas white.................................................................. N. curtipalea

- Venation penninervous; disc florets per capitulum 40–50, corollas yellow or yellow to purplish .................................................12.

12. Petioles 10.3–14.2 mm long; cypselae 1.9–2 mm long, pappus 60–70 bristles ............................................................ N. cobanensis

- Petioles 3.5–8 mm long; cypselae 1.3–1.5 mm long, pappus 30–50 bristles ..................................................................................13.

13. Leaves 2.6–18 cm wide, leaf blade lobed; involucre 7-seriate; pappus 40–50 bristles................................................... N. oaxacana

- Leaves 1.5–2 cm wide, leaf blade entire; involucre 4–5-seriate; pappus ca. 30 bristles.................................................. N. serboana