Key to the genera of the Heliantheae
1. |
Capitula unisexual with male and female florets in separate capitula on same plant |
2 |
Capitula all bisexual, all alike, both male and female florets in each capitulum or disc florets hermaphrodite |
3 |
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2. (1) |
Female capitula with 1 floret, smooth to rugose or verrucose outside, with one apical beak |
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2. |
Female capitula with 2 florets, covered outside with hooked spines with 2 apical beaks |
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3. (1) |
Achenes (at least central) with pappus of retrorsely barbed awns |
4 |
Achenes lacking retrorsely barbed awns, pappus segments often antrorsely scabrid or plumose or absent |
7 |
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4. (3) |
Ray achenes obovate, without awns; disc achenes elongate, mostly beaked and with awns |
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Ray and disc achenes mostly alike, all with similar pappus |
5 |
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5. (4) |
Lianas; pappus awns clustered in 2 groups on apical lobes of achenes |
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Plants mostly erect or decumbent; pappus awns not clustered |
6 |
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6. (5) |
Anther filaments pubescent; achenes rostate, usually quadrangular and furrowed |
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Anther filaments glabrous; achenes erostrate, not furrowed or irregularly furrowed |
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7. (3) |
Leaf lamina, sometimes phyllaries or even corollas with obvious included glandular dots |
8 |
Leaf lamina and other parts lacking included glandular dots, with glandular dots on surface, glandular-stipitate or eglandular |
11 |
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8. (7) |
Phyllaries connate into tube, sometimes splitting with age |
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Phyllaries free (rarely connate only at very base), separately attached to receptacle |
9 |
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9. (8) |
Phyllaries biseriate; capitula calyculate; pappus of squamellae markedly divided into coarsely barbellate flattened setae |
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Phyllaries uniseriate; capitula ecalyculate; pappus of hair-like setae or of aristate squamellae |
10 |
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10. (9) |
Capitula radiate; phyllaries articulated at base; leaf bases distinctly ciliate, sessile, bases only slightly narrowed |
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Capitula discoid; phyllaries not articulate at base; leaves lacking basal cilia, distinctly petiolate or sessile |
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11. (7) |
Capitula axillary, solitary, sessile; paleae tightly conduplicate about achenes; plants aquatic or of marshy areas |
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Capitula terminal, or if axillary or solitary distinctly pedicellate; paleae, when present, not tightly conduplicate about achenes; plants of various habitats, rarely of marshy areas |
12 |
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12. (11) |
Disc florets functionally male, often with undivided style arms; disc achenes undeveloped |
13 |
Disc florets hermaphrodite with functional style arms; disc achenes fertile |
18 |
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13. (12) |
Ray achenes completely enclosed in spiny phyllaries |
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Ray achenes not enclosed in spiny phyllaries |
14 |
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14. (13) |
Ray achenes with marginally attached paleae |
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Ray achenes without marginally attached paleae |
15 |
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15. (14) |
Female floret corollas tubular, with minute limb or small lobules |
16 |
Female floret corollas with enlarged limb |
17 |
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16. (15) |
Inflorescences usually of numerous loosely aggregated capitula; phyllaries and paleae without obvious longitudinal resin ducts; achenes without furrows or ribs; plants shrubs or small trees |
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Inflorescences usually of many capitula in dense terminal glomerules; phyllaries and paleae with obvious resin ducts; achenes with obvious furrows or ribs; plants perennial herbs or subshrubs to shrubs |
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17. (15) |
Phyllaries distinctly biseriate, outer series spreading and foliaceous, inner enclosing ray achenes with large glandular-stipitate glands on outer surface; petioles broad and partly or completely winged |
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Outer phyllaries not large and foliaceous, inner phyllaries subtending ray achenes without stipitate-glands on outer surface; petioles slender and wingless |
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18. (12) |
Florets in capitula or capitula-like structures individually surrounded by radially symmetrical bracts, sometimes considered compound heads of many single-flowered capitula |
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Florets in heads or head-like structures not surrounded with radially symmetrical bracts; capitula with 2 or more florets |
19 |
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19. (18) |
Ray florets absent or sterile, not female |
20 |
Ray florets fertile, female |
38 |
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20. (19) |
Plants resinous |
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Plants not resinous |
21 |
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21. (20) |
Achenes prismatic or broadly quadrangular |
22 |
Achenes flattened, compressed or obcompressed |
26 |
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22. (21) |
Leaves alternate; pappus of relatively long capillary setae |
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Leaves opposite (rarely leaves alternate or whorled); pappus absent, or of short, medium or long squamellae, or of short capillary setae |
23 |
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23. (22) |
Annual or short-lived perennial herbs; mature achenes roughened; anthers free |
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Perennial herbs, subshrubs or shrubs, sometimes scandent; mature achenes smooth; anthers connate |
24 |
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24. (23) |
Pappus of short, medium or long scales; disc corollas with reddish resin ducts |
Calea p.p. |
Pappus absent or of short deciduous setae; disc corollas with colourless resin ducts |
25 |
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25. (24) |
Corollas white; achenes not fleshy; pappus setae deciduous of few short setae |
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Corollas yellow; achenes with fleshy surface; epappose |
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26. (21) |
All achenes obcompressed, flattened on inner and outer surfaces; paleae flat |
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Disc achenes laterally compressed; paleae conduplicate about achenes or paleae absent |
27 |
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27. (26) |
Capitula lacking ray florets |
28 |
Capitula radiate |
31 |
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28. (27) |
Capitula with 3-5 disc florets; receptacle small, epaleaceous, not conical; achenes with internal pale striations |
29 |
Capitula with 14-240 disc florets; receptacle large, obviously paleaceous, conical; achenes lacking pale striations in phytomelanin layer |
30 |
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29. (28) |
Achenes with prominent basal elaiosome, body wingless and short-setuliferous throughout; pappus a fringe of short scales |
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Achene lacking elaiosome, body wings lacerate to crenellate, setuliferous only towards apex; pappus of 2 short, thick hispid awns |
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30. (28) |
Shrubs or vines; inflorescence thyrsoid with corymbose branches |
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Perennial herbs; inflorescences or solitary long-pedicellate capitula |
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31. (27) |
Achenes winged |
32 |
Achenes usually terete or angled but lacking wings |
33 |
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32. (31) |
Involucre with distinct outer series of foliaceous bracts; body of achene not constricted into neck; style arms strongly coiled |
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Involucre lacking outer foliaceous bracts; body of achene constricted above into neck; style arms recurved |
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33. (31) |
Inner phyllaries broadly rounded; leaves opposite; achenes lacking pale striations in phytomelanin layer; sick style arms with two separate stigmatic lines |
34 |
Inner phyllaries narrow, acute; leaves often alternate; achenes with pale striations in phytomelanin layer; disk style arms with one continuous stigmatic surface on inside or each |
35 |
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34. (33) |
Achenes with narrow bases, lacking elaiosome; Pappus a short laciniate crown, lacking neck at apex of achene |
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Achenes with broad bases, with small or large elaiosome; pappus of squamellae fused into short crown above a short neck with 1-3 awns (rarely awns absent) |
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35. (33) |
Pedicel inflated and fistulose beneath involucre |
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Pedicel not inflated or fistulose beneath involucre |
36 |
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36. (35) |
Style arms of disk florets with long slender apical appendages |
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Style arms lacking apical appendage or with only short appendages |
37 |
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37. (36) |
Pappus awns easily deciduous |
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Pappus awns persistent or achenes epappose |
38 |
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38. (37) |
Basal secondary veins of leaf strongly divergent from basal leaf margins; style arms apices with projecting appendage; ray florets 6-11 |
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Basal secondary veins subparallel with and close to basal margins of lamina; style arm apices with out appendage, with or without projecting cell tips; ray florets 14-32 |
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39. (19) |
Capitula with 1 or 2 rays asymmetrically arranged |
40 |
Capitula with 3 or more radially arranged rays |
41 |
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40. (39) |
Capitula with few to many florets enclosed in radially symmetrical involucre; both radiate and discoid capitula present in inflorescence, and if radiate with only 1 or 2 ray florets; achenes 10-ribbed, somewhat flattened |
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Capitula obcompressed, with 2 or 5 florets enclosed in zygomorphic involucre of 1 or 2 greatly enlarged round phyllaries; all capitula radiate; achenes triquetrous |
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41. (39) |
Receptacles epaleaceous |
42 |
Receptacles paleaceous, paleae broad or filiform |
44 |
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42. (41) |
Achenes epappose |
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Achenes pappose |
43 |
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43. (42) |
Phyllary margins membranaceous; involucre obovate or obtrullate in outline; pedicel not enlarged beneath involucre; style arms acute |
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Phyllary margins herbaceous; involucre campanulate or hemispherical; pedicel enlarged beneath involucre; style arms truncate |
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44. (41) |
Achenes of ray florets with marginal wing with many deep narrow lobes |
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Achenes of ray florets without many-lobed wings, usually wingless |
45 |
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45. (44) |
Ray florets with large, persistent corollas on achenes (i.e. abscission zone absent) |
46 |
Ray florets with small corollas or deciduous |
48 |
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46. (45) |
Phyllaries gradate; disc florets functionally male |
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Phyllaries subequal in length; disc florets hermaphrodite |
47 |
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47. (46) |
Ray achenes with pappus of few teeth or a minute rim; capitula distinctly pedicellate, pedicels inflated beneath involucre; ray corollas with tube |
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Ray achenes with pappus of 3 stout spine-like awns and one broader awn; capitula sessile; ray corollas without tube |
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48. (45) |
Disk achenes laterally compressed, sometimes with marginal wings |
49 |
Disk achenes terete or prismatic, often quadrangular |
55 |
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49. (48) |
Achenes constricted beneath pappus or with short neck or beak |
50 |
Achenes not constricted beneath pappus, or slightly narrower beneath pappus |
51 |
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50. (49) |
Plants mainly prostrate; capitula solitary on erect pedicels; achenes without distinct carpopodium or elaiosomes at base, beak and pappus obscured at maturity by corky collar, body conspicuously tuberculate |
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Plants mostly erect or shrubby; capitula rarely solitary; achenes with distinct carpopodium and elaiosomes at base; beak and pappus not obscured at maturity by corky collar, body smooth or only slightly tuberculate |
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51. (49) |
Receptacle markedly conical or ±columnar |
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Receptacle flat or convex to only slightly conical |
52 |
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52. (51) |
Scrambling shrubs or vines; branches short, squarrose |
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Erect herbs or subshrubs; branches not squarrose |
53 |
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53. (52) |
Achenes dimorphic (ray achenes somewhat clavate and unwinged, disc achenes compressed and prominently winged); pappus absent; style arms with penicillate appendages as long as or much longer than stgmatic area |
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Achenes monomorphic; pappus of 2 apical awns; style arm appendages shorter than stigmatic area |
54 |
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54. (53) |
Corollas mostly deep purple or yellowish-purple, sometimes pink; achenes wingless; leaves more or less rosulate and basal; rootstock xylopodiaceous or tuberous |
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Corollas yellow white or orange; achenes broadly winged; leaves often cauline; rootstock fibrous or with distinct taproot |
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55. (48) |
Achenes epappose |
56 |
Achenes with pappus setae or awns or scales |
59 |
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56. (55) |
Outer phyllaries spreading and with many stipitate glands |
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Outer phyllaries not spreading and eglandular |
57 |
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57. (56) |
Capitula sessile at anthesis but elongating after; small turf plants of high elevations |
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Pedicels not elongating after anthesis |
58 |
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58. (57) |
Paleae filiform; phyllaries not equal in number to ray florets and not conduplicate about ray achenes; receptacle slightly convex; achenes tuberculate |
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Paleae broad; phyllaries equal in number to ray florets and partially conduplicate about ray achenes; receptacle conical; achenes smooth |
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59. (55) |
Pappus of many long barbellate or plumose setae |
60 |
Pappus of awns or scales |
61 |
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60. (59) |
Pappus of barbellate capillary setae, somewhat deciduous; inflorescence a very many-headed corymbose-panicle |
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Pappus of plumose setae, persistent; inflorescence scapiform or a few-headed cymose-panicle |
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61. (59) |
Ray corollas yellow; ray achenes and disk achenes with similar pappus |
Calea p.p. |
Ray corollas whitish or purplish; ray achenes with reduced pappus or pappus absent |
