Sticherus, Presl, 1836

Gonzales, Jasivia & Kessler, Michael, 2011, A synopsis of the Neotropical species of Sticherus (Gleicheniaceae), with descriptions of nine new species, Phytotaxa 31, pp. 1-54 : 11-14

Key to the Neotropical species of Sticherus and some of the interspecific hybrids

1. Blades once-pinnate ........................................................................................................................................ S. simplex

– Blades two-pinnate or more divided ............................................................................................................................ 2

2. Segments rounded, oval, or triangular, to 1 cm long ................................................................................................... 3

– Segments linear or oval, over 1 cm long .................................................................................................................. 17

3. Segments rounded, to 0.5 cm long ............................................................................................................................... 4

– Segments rounded or triangular, 0.5–1 cm long .......................................................................................................... 5

4. Abaxial segment surfaces sparsely scaly or glabrous and papillate; bud scales ciliate ............................. S. gnidioides

– Abaxial segment surfaces densely scaly, with dark orange, arachnoid scales; bud scales entire ............. S. maritimus

5. Segments glabrous on both sides ................................................................................................................................ 6

– Abaxial segment surfaces or midveins scaly ................................................................................................................ 7

6. All branches bearing segments; bud scales ciliate, with dark bases.............................................................. S. gracilis

– Only ultimate branches bearing segments; bud scales entire, with dark margins ................................... S. hypoleucus

7. Abaxial segment surfaces glabrous or sparsely scaly; midvein scales linear to filamentous ..................................... 8

– Abaxial segment surfaces densely scaly with arachnoid scales; midvein scales lanceolate or triangular to ovate .. 12

8. Aphlebiae present; bud scales to 1 mm long .............................................................................................................. 9

– Aphlebiae absent or rudimentary; bud scales over 1 mm long .................................................................................. 10

9. Rhizome lacking squamophores; bud scales bicolorous, pale orange with dark brown bases ................... S. pruinosus

– Rhizomes bearing squamophores; bud scales concolorous, orange ........................................................... S. revolutus

10. Segments triangular; midvein scales Y-shaped ...................................................................................... S. strictissimus

– Segments ovate; midvein scales lanceolate to linear ................................................................................................. 11

11. Rhizomes lacking squamophores; bud scales bicolorous, pale orange with dark brown bases .............. S. boliviensis

– Rhizomes bearing squamophores; bud scales concolorous, dull orange ..................................................... S. nervatus

12. Last branches bearing internal segments longer than broad; bud scales ovate, uniformely translucent, ciliate......... 13

– Last branches with semicircular to winglike internal segments broader than long; bud scales lanceolate, bicolorous, ciliate and/or setulose ................................................................................................................................................. 14

13. Veinlets abaxially slender, moderately raised; midvein scales lanceolate ........................................ S. brevitomentosus

– Veinlets abaxially thick, raised; midvein scales ovate to triangular ................................................................ S. ovatus

14. Abaxial segment surfaces densely scaly; veinlets thick, raised ................................................................................. 15

– Abaxial segment surfaces sparsely scaly; veinlets thin, not raised ............................................................................ 16

15. Midvein scales 0.2–0.4 × 0.1–0.2 mm, triangular to round; segments abaxially with translucent or light orange scales ................................................................................................................................................................ S. aurantiacus

– Midvein scales 0.4–2.0 × 0.05–0.20 mm, narrowly rectangular to linear; segments abaxially with reddish brown to cinnamon scales ......................................................................................................................................... S. tepuiensis

16. Aphlebiae usually absent; broad midvein scales 0.2–0.4 × 0.1 mm (linear scales are also present); bud scales bicolorous, dark-speckled ....................................................................................................................................... S. fulvus

– Aphlebiae present; broad midvein scales 0.3–0.6 × 0.3–0.4 mm (linear scales are also present); bud scales bicolorous, apically dark .............................................................................................................................................. S. fuscus

17. Bud scales entire ....................................................................................................................................................... 18

– Bud scales ciliate and/or setulose .............................................................................................................................. 22

18. Segments triangular, broadly adnate; bud scales lanceolate, with dark margins .................................... S. hypoleucus

– Segments linear to triangular, basally hastulate, shortly petiolate or adnate; bud scales ovate, translucent ............. 19

19. Petioles over 3 mm thick; all branches segmented; proximal branches with auriculate segments; distal branches with adnate segments ...................................................................................................................................... S. intermedius

– Petioles to 2 mm thick ............................................................................................................................................... 20

20. 1 st branches segmented, the segments adnate; branches diverging at angles to 130°, slightly flexuose; rhizomes rugose ..................................................................................................................................................... S. orthocladus – 1 st branches not segmented, the segments semiadnate to auriculate; branches diverging at angles over 130°, slightly to strongly flexuose; rhizomes smooth ..................................................................................................................... 21

21. Branches slightly flexuose; segment bases shortly petiolate, auriculate; segments 0.4–2.5 cm long ...... S. hastulatus

– Branches strongly flexuose; segment bases semiadnate, basiscopically auriculate; segments 2–3 cm long ................. ................................................................................................................................................................... S. retroflexus

22. Abaxial segment surfaces densely scaly throughout .................................................................................................. 23

– Abaxial segment surfaces glabrous or sparsely scaly or scaly only on midveins....................................................... 29

23. Bud scales translucent with dark parts; plants usually slender .................................................................................. 13

– Bud scales translucent, lacking dark parts; plants usually robust .............................................................................. 24

24. All scales dark orange to cinnamon; abaxial segment surfaces densely scaly; midvein scales lanceolate or stellate ... ................................................................................................................................................................................... 25

– All scales whitish to pale orange; abaxial segment surfaces sparsely to densely scaly; midvein scales rectangular to linear. ......................................................................................................................................................................... 27

25. Pinnae more than 3-forked; all branches pectinate, linear; segments oblong, to 2 cm long ............................. S. rufus

– Pinnae to 3-forked; only last branch fully pectinate, lanceolate; segments linear,> 2.5 cm long ............................. 26

26. Segments linear, to 2 mm wide; midvein scales stellate; aphlebiae narrow, trifid; fiddleheads matted with appressed scales ...................................................................................................................................................... S. chocoensis

– Segments oblong, over 3 mm wide; midvein scales lanceolate; aphlebiae pinnatifid to trifid; fiddleheads densely scaly with erect, spreading scales ............................................................................................................ S. tomentosus

27. Segments linear; bud scales narrowly lanceolate, with lattice-like cell structure, sometimes basally semi-rigid but not dark in color ....................................................................................................................................... S. ferrugineus

– Segments oblong; bud scales lanceolate, translucent, basally or on margins darker ................................................ 28

28. Pinnae to 3-forked; only last branch fully pectinate, linear; segments to 2 cm long; segments within a pinna of roughly equal size; bud scales basally darker, margins with abundant, delicate cilia; northern Andes ......................... .............................................................................................................................................................. S. arachnoideus

– Pinnae more than 3-forked; segments unequal in length, 1–3 cm long; proximal branches internally pectinate; last branch lanceolate, usually narrower than the proximal ones; bud scales translucent with dark margins bearing short, delicate cilia; Greater Antilles ................................................................................................................... S. antillensis

29. All scales ovate, entire or short-ciliate, translucent; aphlebiae lacking ..................................................................... 30

– All scales lanceolate, ciliate or setulose, translucent to bicolorous; aphlebiae present or lacking ............................ 31

30. 1 st branches arching, usually longer than the 2 nd; segments oblong, 1.5–3.0 cm × 2.0– 3.5 mm; rhizome scales lanceolate, rigid ........................................................................................................................................................ S. nudus

– 1 st branches straight, similar in length to the 2 nd; segments linear, obtuse, 1.5–2.0 cm × 2.0– 2.5 mm; rhizome scales ovate, translucent ...................................................................................................................................... S. pteridellus

31. Segments remote at least on the proximal branches; scales abaxially on branches bicolorous with dark bases, apices, or centers .................................................................................................................................................................... 32

– Segments approximate on all branches; segments linear to oblong; scales abaxially on branches translucent or centrally darkened ........................................................................................................................................................... 39

32. Branches more than 3-forked; midvein scales filamentous, translucent, whitish ............................. S. moyobambensis

– Branches less than 3(-4)-forked; midvein scales lanceolate ....................................................................................... 33

33. Aphlebiae lacking; bud scales entirely dark ...................................................................................... S. melanoblastus

– Aphlebiae present, bud scales bicolorous or entirely dark ....................................................................................... 34

34. Bud scales with dark apices........................................................................................................................................ 35

– Bud scales with dark bases or centers or entirely dark ............................................................................................. 37

35. All branches remotely pinnatisect, midvein scales stellate; sori not nested within arachnoid scales ........... S. remotus

– Only 1 st branches remotely pinnatisect; midvein scales linear and/or triangular; sori nested within arachnoid scales. .................................................................................................................................................................................... 36

36. 1 st branches longer than 2 nd; branches lacking wings between segments; abaxial segment surfaces densely scaly; Bolivia. .............................................................................................................................................................. S. jacha

– 1 st branches shorter than 2 nd; branches with wings between the segments; abaxial segment surfaces sparsely scaly; southeastern Brazil and Bolivia........................................................................................................ S. nigropaleaceus

37. Bud scales lanceolate-subulate, with dark centers; midvein scales stellate .............................................. S. interjectus

– Bud scales lanceolate, with dark bases; midvein scales loosely stellate ................................................................... 38

38. Segments to 3.5 cm long; branches with wings between segments .................................................... S. × subremotus

– Segments> 3.0 cm long; branches lacking wings between segments .............................................. S. ×pseudobifidus

39. Ultimate branches with numerous reduced winglike internal proximal segments ................................................... 15

– Ultimate branches with internal segments lacking or gradually reduced .................................................................. 40

40. Aphlebiae lacking; last branches lacking proximal internal segments, branch outlines lanceolate, basally equally or unequally truncate ...................................................................................................................................................... 41

– Aphlebiae trifid to simple; last branches with proximal internal segments gradually reduced, branch outlines lanceolate or linear .............................................................................................................................................................. 43

41. Veinlets abaxially slightly raised; bud scales lanceolate, with numerous delicate cilia ................................ S. bifidus

– Veinlets strongly raised; bud scales rounded, entire or irregularly cilate .................................................................. 42

42. Bud scales bicolorous with dark centers and translucent margins, lanceolate, basally cordate; midvein scales imbricate, short-lanceolate to linear, translucent; rhizome scales lanceolate, dark ................................. S. brevitomentosus

– Bud scales concolorous, with lattice-like cell structure, translucent, rounded, glandular; midvein scales not imbricate, rounded; rhizome scales ovate, translucent ............................................................................................. S. ovatus

43. Bud scales completely dark or bicolorous with dark apices or scattered dark patches, margins setose and/or ciliate .. ................................................................................................................................................................................... 44

– Bud scales concolorous and translucent, or bicolorous with dark bases, margins with delicate or short, thick cilia .... ................................................................................................................................................................................... 47

44. Abaxial branch scales completely dark or bicolorous with translucent bases and dark apices; abaxial segment surfaces with dark orange scales; segments oblong, to 2 cm long........................................................................ S. fuscus

– Abaxial branch scales translucent or occasionally with dark apices; abaxial segment surface with whitish to pale orange scales; segments linear, to 3 cm long ............................................................................................................. 45

45. Aphlebiae slightly pinnatifid; Bolivia and Brazil...................................................................................... S. decurrens

– Aphlebiae narrow, trifid; Caribbean and northern South America ........................................................................... 46

46. 1 st branches to 4 cm long; opposite pairs of branches roughly equal in length; all branches pinnatifid ....... S. cubensis

– 1 st branches over 5 cm long; opposite pairs of branches strongly unequal in length; proximal branches remotely pectinate and distally pinnatifid ............................................................................................................. S. × pseudobifidus

47. Midvein scales Y-shaped to linear or stellate ............................................................................................................. 48

– Midvein scales lanceolate to linear-lanceolate or filamentous .................................................................................. 51

48. All scales dark brown; midvein scales anchor-shaped with a long apical cilium and two lateral cilia.......................... .............................................................................................................................................................. S. longipinnatus

– All scales bicolorous, dark brown and translucent; midvein scales stellate or Y-shaped ......................................... 49

49. Veinlets slender, not raised; midvein scales stellate, proximally with some dark cilia, distally translucent ................. .................................................................................................................................................................. S. compactus

– Veinlets thick or slender, moderately to strongly raised; midvein scales Y-shaped, translucent ............................... 50

50. Plants robust, more than 2-forked; veinlets thick, strongly raised ............................................................... S. brittonii

– Plants slender, to 2-forked; veinlets slender, moderately raised ............................................................ S. strictissimus

51. Midvein scales filamentous; branches more than 3-forked ...................................................................................... 52

– Midvein glabrous or with lanceolate to linear scales; branches to 3-forked, rarely more divided............................. 54

52. Midvein scales dark orange to cinnamon; proximal branches slender, unequal in length, spreading at ca. 90°, with ca. 2 segments per cm ............................................................................................................................. S. squamosus

– Midvein scales whitish to pale orange; proximal branches thick or slender, usually equal in length, spreading at angles to 45°, with ca. 2–3 segments per cm ............................................................................................................ 53

53. Proximal branches thick, very short; segments 0.5–2.0 cm long, ca. 3 segments per cm ...................... S. lanuginosus

– Proximal branches usually slender; segments more than 3 cm long, ca. 2 segments per cm ......................... S. velatus

54. Plants usually robust; segments more than 3 cm long; bud scales thick-textured...................................................... 55

– Plants usually slender or medium-sized; segments to 3 cm long; bud scales thin-textured ..................................... 58

55. Only proximal branches abaxially scaly; bud scales whitish ................................................................... S. pallescens

– All branches abaxially scaly; bud scales whitish or bicolorous with dark brown parts ............................................. 56

56. Veinlets glabrous; sori not nested in arachnoid scales; bud scales whitish ..................................................... S. albus

– Veinlets glabrous to densely scaly; sori nested in arachnoid scales; bud scales usually bicolorous ......................... 57

57. 1 st branches longer than 2 nd; veinlets glabrous to sparsely scaly; bud scales basally dark brown with occluded cells. ............................................................................................................................................................. S. blepharolepis

– 1 st branches shorter than 2 nd; veinlets densely scaly; bud scales basally dark brown with translucent cells ................. ........................................................................................................................................................................ S. lanosus

58. Bud scales translucent with dark margins ................................................................................................................. 59

– Bud scales entirely translucent or with dark bases or centers ................................................................................... 60

59. Veinlets with simple, whitish hair-like scales; abaxial segment surfaces densely papillose; West Indies .................... ..................................................................................................................................................................... S. farinosus

– Veinlets with contorted to linear, orange, hair-like scales; abaxial segments surfaces smooth; Central and South America ................................................................................................................................................... S. rubiginosus

60. Midveins sparsely scaly to glabrous; bud scales translucent, orange ....................................................................... 61

– Midveins densely scaly; bud scales translucent or bicolorous, orange to orange with dark parts ............................ 62

61. Proximal branches not pectinate; aphlebiae broad; only last two distal branches pectinate; rhizomes bearing squamophores; Central Andes .................................................................................................................................. S. lechleri

– Proximal branches internally pectinate; aphlebiae narrow; all branches pectinate; rhizomes lacking squamophores; West Indies ............................................................................................................................................ S. jamaicensis

62. Segments ovate, revolute, to 1 cm long; scales concolorous, orange ......................................................................... 9

– Segments triangular to linear, usually over 1 cm long; scales bicolorous .................................................................. 63

63. 1 st branches slightly remotely pectinate; segment margins glabrous; veinlets glabrous .............................. S. × leonis

– 1 st branch pinnatisect; segment margins ciliate or glabrous; veinlets sparsely scaly ................................................ 64

64. Segment margins ciliate; midvein and veinlet scales whitish ...................................................................... S. furcatus

– Segment margins glabrous; midvein and veinlet scales orange ................................................................................ 65

65. Bud scales bicolorous, translucent and whitish with dark brown bases; proximal branches slightly arched, not pectinate; South America ................................................................................................................................ S. peruvianus

– Bud scales gradually bicolorous, brilliant orange with darker bases; proximal branches straight, pinnatifid to pinnatisect; Central America .................................................................................................................... S. underwoodianus