Key to the genera of the Eupatorieae

1.

Phyllaries distant and bases not articulated; receptacles epaleaceous unsclerified, and changing shape with maturity (subtribe Adenostemmatinae)

2

 

Phyllaries distant to imbricate and bases sclerified or articulated; receptacle sclerified between areolae or paleaceous

3

2. (1)

Pappus absent

Gymnocoronis

 

Pappus of 3 or 5 elongate knobs

Adenostemma

3. (1)

Capitula with 4 subequal phyllaries and 4 florets, usually with a fifth unequal subinvolucral bract (subtending the involucre or pedicel); style arms never with clavate apices; pappus always present (subtribe Mikaniinae)

Mikania

 

Capitula without 4 subequal phyllaries and 4 florets or with clavate style arms apices or with a defective pappus

4

4. (3)

Phyllaries all deciduous leaving a naked receptacle, remaining appressed until lost, not spreading with age (subtribe Praxelinae)

5

 

At least some basal phyllaries persistent, phyllaries usually spreading with age

6

5. (4)

Receptacle conical

Praxelis

 

Receptacle flat to slightly convex

Chromolaena

6. (4)

Corolla lobes (usually) smooth on inner surface

7

 

Corolla lobes papillose on inner surface

18

7. (6)

Pappus of awns, scales, crowns, or absent, never of wingless setae; pappus awns bristle-like in some 5-flowered species; plants rarely with densely spirally inserted leaves (subtribe Ageratinae)

8

 

Pappus of capillary setae, sometimes short, rarely absent in some plants with densely spirally inserted leaves; capitula rarely with less than 6 florets

9

8. (7)

Florets and phyllaries 5

Stevia

 

Florets and phyllaries not equal in number, > 20

Ageratum

9. (7)

Style base usually with a distinct glabrous node; phyllaries usually distant and subequal (subtribe Oxylobinae)

10

 

Style base lacking basal node; phyllaries distant or subimbricate, usually gradate

11

10. (9)

Pappus setae easily deciduous

Ageratina

 

Pappus setae persistent

Kaunia

11. (9)

Receptacles convex to conical; style arms linear or with broadened apices; anther collars usually conspicuous and expanded; cells of inner surface of corolla lobes short and essentially isodiametric (subtribe Gyptidinae)

12

 

Receptacles usually flat; style arms filiform; anther collars scarcely discernible and cylindrical; cells of inner surface of corolla lobes elongate with upper ends projecting as papillae (subtribe Fleischmaniinae)

Fleischmannia

12. (11)

Pappus of plumose or markedly barbellate setae or absent and corollas densely pubescent, pubescence obscuring lobes

Trichogonia

 

Pappus barbellate, rarely simple, if absent then corollas lacking dense pubescence, or pubescence not obscuring lobes

13

13. (12)

Achenes with stipitate or long-attenuate bases

14

 

Achenes of uniform diameter or only slightly narrowed towards base

15

14. (13)

Capitula large, florets 30-100; receptacle conical or highly convex; achene ribs pale

Campuloclinium

 

Capitula small to medium, florets < 50; receptacle flat or slightly convex; achene ribs concolorous with body

Neocuatrecasia

15. (13)

Carpopodium procurrent on base of achene ribs

16

 

Carpopodium stopper-shaped

17

16. (15)

Achenes setuliferous; style base with swollen basal node, pubescent

Dasycondylus

 

Achenes glandular-punctate; style base lacking basal node, glabrous

Barrosoa

17. (15)

Pappus setae with blunt, sometimes inflated apices; phyllaries with distinct pubescent appendages

Urolepis

 

Pappus setae with acute apices; phyllaries lacking pubescent apical appendages

Bejaranoa

18. (6)

Style arms long-clavate, thickened in both width and thickness, few exceptions with 10-ribbed achenes, plumose pappus or those with peg-like setulae on achenes; upper corolla limb often constricted beneath corolla lobes (subtribe Alomiinae)

19

 

Style arms not thickened or thickened only at tips, if long-clavate then flattened; achenes never 10-ribbed, never with plumose pappus setae and never with peg-like eglandular achene setulae; corolla limb cylindrical or funnelform beneath corolla lobes

21

19. (18)

Style base with distinctly enlarged basal node; corollas glabrous outside

20

 

Style base lacking enlarged basal node; corollas glandular-punctate outside

Helogyne

20. (19)

Achenes 8-10-ribbed; annual herb

Brickellia diffusa

 

Achenes 5-ribbed; erect or spreading to arching subshrubs or shrubs

Austrobrickellia

21. (18)

Style base glabrous and basal node absent; inner phyllaries usually deciduous

22

 

Style base with basal node or pubescent or both

33

22. (21)

Capitula always with 5 florets; style arm apices papillose; pappus setae sometimes with bulbous-tipped apical cells; plants of eastern South America (subtribe Disynaphiinae)

23

 

Capitula with 1-300 florets, rarely consistently 5-flowered; style arms usually smooth at least at apices; pappus setae never with bulbous-tipped apical cells; plants throughout tropical and subtropical America

25

23. (22)

Leaves pinnately or bipinnately lobed; style arm appendages with long narrow papillae

Acanthostyles

 

Leaves simple; style arms appendages short-papillose

24

24. (23)

Inflorescences densely paniculate

Raulinoreitzia

 

Inflorescences densely corymbose

Campovassouria

25. (22)

Receptacles glabrous; anther collar usually less than 5 times as long as wide (subtribe Critoniinae)

26

 

Receptacles usually pubescent; anther collar usually more than 5 times as long as wide (subtribe Hebecliniinae)

Hebeclinium

26. (25)

Leaves distinctly alternate

Bishovia

 

Leaves mostly opposite or subopposite

27

27. (26)

Phyllaries distant or weakly subimbricate in up to 3 rather irregular series

28

 

phyllaries subimbricate or imbricate in 4 or more gradate series, inner phyllaries sometimes easily deciduous

30

28. (27)

Apical anther appendages absent, often appearing as two minute lobes; phyllaries distant

Ophryosporus

 

Apical anther appendages distinct, 1/3 as long as wide or longer; phyllaries weakly subimbircate

29

29. (28)

Capitula in dense spherical clusters

Sphaereupatorium

 

Capitula not in dense spherical clusters

Koanophyllon

30. (27)

Apical anther appendages shorter than wide, truncate to bilobed; style arms often with abruptly enlarged apices

Koanophyllon

 

Apical anther appendages about as long as wide or longer, usually with rounded apices, rarely retuse; style arms with abruptly enlarged apices in some Critonia

31

31. (30)

Leaves with translucent or lens-like secretory pockets when viewed against light, lacking glandular-punctae; coarse vines and shrubs

Critonia

 

Leaves lacking secretory pockets, often with glandular-punctae

32

32. (31)

Pappus setae with markedly dilated spinose apices; capitula with 50-70 florets

Amboroa

 

Pappus setae without dilated or spinose apices; capitula with 10-12 florets

Lorentzianthus

33. (21)

Style base lacking basal node, pubescent; capitula with less than 20 florets; receptacles epaleaceous; apical cells of pappus setae usually rounded (subtribe Eupatoriinae)

34

 

Style base inflated above nectary, glabrous or pubescent; capitula usually with more than 20 florets, sometimes receptacle paleaceous; apical cells of pappus setae acute (subtribe Ayapaninae)

36

34. (33)

Achene body setuliferous

35

 

Achene body only with glands

Austroeupatorium

35. (34)

Inflorescences pyramidal or thyrsoid

Stomatanthes

 

Inflorescences corymbose

Hatschbachiella

36. (33)

Corollas with conspicuously constricted basal tube

Condylidium

 

Corollas funnelform or narrow and tubular

37

37. (36)

Scandent shrubs; inflorescences with distinct cymose branching

Heterocondylus

 

Herbs or subshrubs; inflorescences corymbose or paniculate and often only with dense cymose terminal branching

38

38. (37)

Anther cylinder included well within corolla tube; florets 5-40 per capitulum; style base with pubescent node

Ayapana

 

Anther cylinder visible in corolla throat

39

39. (38)

Corolla tube funnelform; corollas pink to violet; florets 25-150 per capitulum; style base with glabrous or pubescent node

Ayapanopsis

 

Corolla tube very narrow and tubular; corollas white; florets 150-300 per capitulum; style base with glabrous node

Polyanthina