Key to the genera of the Vernonieae

1.

Achenes strongly compressed with 2 horn-like apical projections

Trichospira

 

Achenes cylindrical with a pappus of awns, capillary hairs or a cartilaginous coronona

2

2. (1)

Inflorescence glomerulose with congested capitula, synflorescence on an elongated scape

3

 

Inflorescence cymose with separate (although sometimes congested) capitula, not scapose, or sessile and axillary

4

3. (2)

Florets 3(2-5) per capitulum; leaves tomentose or glabrate; corollas tube about twice as long as corolla lobes

Chresta

 

Florets (4-) 6-12 per capitulum; leaves glabrate, membranous; corolla tube between 2-4.5 times as long as corolla lobes

Pycnocephalum

4. (2)

Corolla with prominent stipitate-glands; capitula terminal on branches; involucre surrounded by foliaceous bracts

Centratherum

 

Corollas lacking stipitate-glands; capitula usually few to many in axillary or terminal inflorescences, if scapose then pedicel ebracteate; involucre not surrounded by foliaceous bracts

5

5. (4)

At least inner phyllaries deciduous

6

 

All phyllaries persistent

7

6. (5)

Usually all phyllaries deciduous (at least in herbarium material); capitula usually in dense axillary or terminal clusters; leaves sometimes opposite; shrubs (sometimes scandent) or trees; pubescence often stellate or lepidote; corolla lobes sometimes strongly coiled

Piptocarpha

 

Only inner phyllaries usually deciduous; capitula in terminal inflorescences; leaves alternate or opposite

Critoniopsis

7. (4)

Florets 2-4 per capitulum; corollas often zygomorphic; involucre usually with 4 pairs of phyllaries

Elephantopus

 

Florets more than 5 per capitulum; corollas actinomorphic; involucre few- to many- seriate

8

8. (7)

Pappus a cartilaginous corona; corollas 3-4-lobed; phyllaries 2-seriate

Struchium

 

Pappus of hair-like or capillary setae; corollas 5-lobed; phyllaries 3-6-seriate

9

9. (8)

Aquatic herbs; capitula axillary, usually solitary

10

 

Terrestrial herbs, shrubs or small trees; capitula numerous, of scorpioid cymes or terminal and solitary

11

10. (9)

Capitula small, 1 (-3) per axil; phyllary margins concolorous; achenes 5-ribbed; style with basal node; leaves not clasping stem; delicate herbs

Xiphochaeta

 

Capitula large, solitary and axillary; phyllary margins whitish; achenes 10-ribbed; style lacking basal node; leaf bases amplexicaul; robust herbs

Pacourina

11. (9)

Pappus of strap-shaped awns

Strophopappus

 

Pappus of capillary setae

12

12. (11)

Corollas with long hairs on inside of throat

Quechualia

 

Corollas lacking long hairs on inside of throat

Vernonia