Keys to the genera of Annonaceae

Abstract

Identification keys are provided for all genera currently recognized in Annonaceae. Separate keys are presented for the Neotropics (34 genera), Africa-Madagascar (40 genera) and Asia-Australasia (42 genera). These keys are based on a combination of vegetative and fertile characters.

identification, synonymy, taxonomy

INTRODUCTION

Annonaceae are a pantropical family of trees, shrubs and lianas. They play an important ecological role in terms of species diversity, especially in tropical rainforest ecosystems. To date, there are 109 validly described and recognized genera and c. 2440 species (Chatrou et al., 2012; Erkens, Mennega & Westra, 2012). Several family-wide keys to the genera have been published in the past (Engler & Diels, 1901; Hutchinson, 1923; Fries, 1959), with the most recent one by Keßler (1993) published almost 20 years ago. Since then, significant taxonomic changes at the generic level have been made, most of them based on molecular phylogenetic studies at the species and generic levels, with the justification to conserve strictly monophyletic genera (see Table 1 for a complete list). Several different types of changes can be identified, including description of genera new to science (Verdcourt, 1996; Couvreur et al., 2009), elevation to the rank of genus of previously described species from different genera (Chatrou, 1998; Mols et al., 2008), reinstatement of generic names formally sunken into other genera (Surveswaran et al., 2010) and generic names reduced to synonymy with other genera (van Heusden, 1994b; Kenfack et al., 2003; Erkens et al., 2007; Rainer, 2007; Zhou, Su & Saunders, 2009; Zhou et al., 2010). Two new generic names were also described and subsequently synonymized: Craibella R. M. K.Saunders, Y. C. F.Su & Chalermglin (Saunders, Su & Chalermglin, 2004), now synonymized with Pseuduvaria Miq. (Su, Smith & Saunders, 2008), and Cleistopetalum Okada (Okada, 1996), which was synonymized into Polyalthia Blume (Turner, 2010). However, Polyalthia, one of the largest genera in Annonaceae, has been shown to be polyphyletic (Mols et al., 2004; Xue et al., 2011) with the species previously described under Cleistopetalum belonging to a clade (Xue et al., 2011) associated with the conserved name Enicosanthum Becc. (Saunders & Xue, 2011). Finally, some genera still have an uncertain status. Oncodostigma Diels was listed as synonym of Meiogyne Miq. by van Heusden (1994b), but the types species (O. leptoneura Diels) was considered as a ‘dubious name’ (the holotype appeared to be a mixed collection), making the transfer of the name Oncodostigma incomplete. Here, we shall consider Oncodostigma as a ‘confused name’ and will not include it into the key. This issue will require future investigation. Furthermore, the genus Friesodielsia Steenis has been shown to be polyphyletic (Richardson et al., 2004; Chatrou et al., 2012): two clades are recognized, an Asian one sister to Desmos Lour. and Dasymaschalon Dalla Torre & Harms and an African one closely related to the African genus Monanthotaxis Baill. The status of both clades of Friesodielsia is not officially recognized yet, and we shall treat the concerned species under the same name. Finally, the taxonomy of Melodorum Lour., Sphaerocoryne Scheff. ex Ridl. and Mitrella Miq. is ambiguous and these genera are in great need of a revision. Following the traditional circumscription of these taxa, we include the liana groups Sphaerocoryne p.p./Melodorum p.p and the arborescent group of Melodorum p.p./Sphaerocoryne p.p. in the key.

Table 1.

Changes in generic status and new genera within Annonaceae since the publication of the last family-wide key of Annonaceae by Keßler (1993). A-AUS, Asia and Australia. NA, not applicable

	Genus	Accepted name	Region	Reference
New genera
	Cleistopetalum	Enicosanthum	A-AUS	(Okada, 1996)
	Craibella	Pseuduvaria	A-AUS	(Saunders et al., 2004)
	Klarobelia Chatrou	NA	Neotropics	(Chatrou, 1998)
	Maasia Mols, Kessler & Rogstad	NA	A-AUS	(Mols et al., 2008)
	Mosannona Chatrou	NA	Neotropics	(Chatrou, 1998)
	Mwasumbia Couvreur & D. M.Johnson	NA	Africa	(Couvreur et al., 2009)
	Pseudomalmea Chatrou	NA	Neotropics	(Chatrou, 1998)
	Sanrafaelia Verdc.	NA	Africa	(Verdcourt, 1996)
Reinstated generic names
	Drepananthus Maingay ex Hook.f.	NA	A-AUS	(Surveswaran et al., 2010)
	Fenerivia Diels*	NA	Madagascar	(Saunders, Su & Xue, 2011)
Genera reduced to synonymy
	Ancana F.Muell.	Meiogyne	A-AUS	(van Heusden, 1994b)
	Anomianthus Zoll.	Uvaria	A-AUS	(Zhou et al., 2009)
	Atopostema Boutique	Monanthotaxis Baill.	Africa	(Verdcourt, 1971)
	Balonga Le Thomas	Uvaria	Africa	(Zhou et al., 2010)
	Chieniodendron Tsiang & P. T.Li	Meiogyne	A-AUS	(van Heusden, 1994b)
	Cleistopetalum†	Enicosanthum	A-AUS	(Turner, 2010)
	Craibella	Pseuduvaria	A-AUS	(Su, Chaowasku & Saunders, 2010)
	Cyathostemma Griff.	Uvaria	A-AUS	(Zhou et al., 2009)
	Dasoclema J. Sinclair	Uvaria	A-AUS	(Zhou et al., 2010)
	Deeringothamnus Small	Asimina Adans.	USA	Abott et al. in prep
	Dennettia Baker f.	Uvariopsis Engl. & Diels	Africa	(Kenfack et al., 2003)
	Ellipeia Hook.f. & Thomson	Uvaria	A-AUS	(Zhou et al., 2009)
	Ellipeiopsis R. E.Fr.	Uvaria	A-AUS	(Zhou et al., 2009)
	Enantia Oliv.‡	Annickia Setten & Maas	Africa	(van Setten & Maas, 1990)
	Fitzalania F. Muell.	Meiogyne	A-AUS	(Chaowasku, Zijlstra & Chatrou, 2011)§
	Guamia Merr.	Meiogyne	A-AUS	(van Heusden, 1994b)
	Guatteriella R. E.Fr.	Guatteria Ruiz. & Pav.	Neotropics	(Erkens et al., 2007)
	Guatteriopsis R. E.Fr.	Guatteria	Neotropics	(Erkens et al., 2007)
	Heteropetalum Benth.	Guatteria	Neotropics	(Erkens et al., 2007)
	Mezzettiopsis Ridl.	Orophea Blume	A-AUS	(Keßler, 1988)
	Oreomitra Diels	Pseuduvaria	A-AUS	(Su et al., 2010)
	Pachypodanthium Engl. & Diels	Duguettia	Africa	(Chatrou, 1998)
	Papualthia Diels	Haplostichanthus F.Muell.	A-AUS	(van Heusden, 1994a)
	Petalolophus K.Schum.	Pseuduvaria	A-AUS	(Su et al., 2005)
	Polyaulax Backer	Meiogyne	A-AUS	(van Heusden, 1994b)
	Raimondia Staff.	Annona	Neotropics	(Rainer, 2001)
	Rauwenhoffia Scheff.	Uvaria	A-AUS	(Zhou et al., 2009)
	Richella A. Gray	Goniothalamus Hook.f. & Thomson	A-AUS	(Nakkuntod et al., 2009)
	Rollinia A.St.-Hil.	Annona	Neotropics	(Rainer, 2007)

*

This name was officially reduced to synonymy with Polyalthia, but was nevertheless included in the Keßler (1993) key.

†

See Introduction.

‡

Although the new name Annickia was given in 1990, it was not adopted in the Keßler (1993) key.

§

This is a nomenclatural proposal and still has to be validated.

In total, eight new generic names have been published since 1993, and 31 have been synonymized (Table 1). These changes clearly warrant new keys to the genera of the family. For a complete list of accepted genera, number of species per genus and a family-level classification see Chatrou et al. (2012) and for an annotated list of all generic names ever published in Annonaceae see Erkens et al. (2012).

MATERIAL AND METHODS

We provide identification keys following three major geographical regions: the Neotropics and the USA, Africa (including Madagascar) and Asia/Australasia (including India, Sri Lanka and the Pacific Islands). This approach was taken because most genera are endemic to these major regions. Only seven genera are shared between two regions: Anaxagorea A.St.-Hil. (Neotropics/Asia), Annona L. (Neotropics/Africa), Artabotrys R.Br. (Palaeotropics), Duguetia A.St.-Hil. (Neotropics/Africa), Friesodielsia and Sphaerocoryne (Palaeotropics, but see above), Uvaria (Palaeotropics); and one between them all: Xylopia L. (pantropical). This provides a faster and easier way to identification than a single comprehensive key. For each genus, we also provide an approximate indication of distribution, which can also help with identification. We tried to use vegetative characters as much as possible, but most of these are coupled with fertile ones (flowers and/or fruits). Only macromorphological characters have been retained in the key (e.g. visible with or without a hand lens) in order to make the key useful to a wide range of users. However, in the South-East Asian key an extra pollen character is indicated in parentheses in addition to fertile ones to help identification as these are easily visible using a hand lens (polyads vs. monads).

Key to neotropical genera of annonaceae (Paul J. M. Maas)

1. Leaves spirally arranged; flowers tetra-(to hexa-)merous; indument of stellate hairs; Amazon region and French Guiana in the north and Pacific coast of Colombia in the west Tetrameranthus

2. Leaves arranged in two rows (distichous); flowers trimerous (rarely dimerous); indument of various types (simple, stellate or scale-like hairs) 2

3. Indument of stellate or scale-like hairs (easily visible with a hand lens); fruit syncarpous; carpels strongly coherent, but only partly connate, lower carpels sterile and often forming a basal collar; from Costa Rica in the north to Bolivia and Paraguay in the south, and Africa Duguetia

4. Indument of simple hairs or lacking (hairs sometimes stellate in Annona, microscopic stellate to furcate hairs occur in Anaxagorea); fruit either apocarpous or syncarpous, but not as above 3

5. Inflorescences axillary (sometimes leaf-opposed in Anaxagorea brevipes) or sometimes arising from trunk (cauliflorous); fruit apocarpous 4

6. Inflorescences leaf-opposed, supra-axillary, or terminal, rarely arising from trunk; fruit apocarpous or syncarpous 22

7. Upper side of leaves with impressed to flat midrib 5

8. Upper side of leaves with raised midrib 14

9. Petals often thick and fleshy (2–10 mm thick) and covered with microscopic, brownish hairs; monocarps club-shaped, explosively dehiscent, two-seeded; throughout Neotropics, except for West Indies, three species in Asia Anaxagorea

10. Petals generally much thinner and covered with much larger hairs or glabrous; monocarps never club-shaped, generally globose to ellipsoid, indehiscent, or non-explosively dehiscent, one- to several-seeded 6

11. Pedicels with a suprabasal articulation (a few mm above base of pedicel); throughout Neotropics Guatteria

12. Pedicels with a basal articulation 7

13. Sepals two; petals four; carpels one (or two); Mexico Tridimeris

14. Sepals three; petals six; carpels generally numerous 8

15. Monocarps dehiscent; seeds distinctly arillate; young twigs mostly lenticellate; leaves generally small and narrow; throughout Neotropics, Africa and Asia Xylopia

16. Monocarps indehiscent; aril absent or indistinct; young twigs not lenticellate; leaves mostly much larger and broader 9

17. Monocarps several-seeded 10

18. Monocarps one-seeded 11

19. Petals white, maroon, rarely yellow, large, 10–80 × 10–50 mm, distinctly veined; inner petals much shorter than outer ones; monocarps one to 12; south-east USA to southern Canada Asimina

20. Petals mostly white, 7–23 × 1–3 mm, with indistinct venation; petals subequal or inner petals longer than outer ones; monocarps one or two; tropical South America, but mainly Amazonian Diclinanona

21. Upper side of leaves with distinctly impressed venation; monocarps long–stipitate (stipes 5–35 mm long); petals 8–12 mm long; tropical South America, but mainly in north-east Brazil Ephedranthus

22. Upper side of leaves with flat, not or slightly impressed venation; monocarps short– to long–stipitate; petals 4–70 mm long 12

23. Pedicels bearing three to six tiny bracts; stipes of monocarps < 8 mm long; petals 4–8 mm long; flowers bisexual, rarely androdioecious (Oxandra venezuelana), stipes < 10 mm long; throughout Neotropics Oxandra

24. Pedicels provided with one or two bracts; stipes of monocarps > 10 mm long, generally much more; petals 7–70 mm long; flowers both staminate and bisexual (staminate and bisexual flowers present) 13

25. Pedicels with bract above articulation; petals 8–21 mm long, spreading and leaving floral centre uncovered; raphe of seeds raised, straight; western South America and adjacent Panama Pseudomalmea

26. Pedicels without bract above articulation; petals 10–30 mm long, concave, covering floral centre; raphe of seeds impressed, straight, slightly sinuous or spiral; tropical South America up to Cost Rica in the north Klarobelia

27. Petals often fleshy (2–10 mm thick), covered with microscopic, brownish hairs; innermost stamens staminodal; monocarps club-shaped, explosively dehiscent, two-seeded; throughout Neotropics, except for West Indies Anaxagorea

28. Petals generally much thinner, covered with much larger hairs or glabrous; all stamens fertile or outermost stamens staminodal (Fusaea); monocarps globose to ellipsoid, indehiscent or non-explosively dehiscent, one- to several-seeded 15

29. Leaves with distinct marginal vein, almost touching margin (except in P. spiritus-sancti); petals 4–15 mm long; tropical South America Pseudoxandra

30. Leaves without marginal vein (except in Oxandra p.p., but then much further removed from margin); petals 4–35 mm long 16

31. Lower side of leaves glaucous; monocarps transversely ellipsoid, one-seeded; petals 25–35 mm long; western part of South America Ruizodendron

32. Lower side of leaves not glaucous; monocarps ellipsoid to globose, one- to several-seeded; petals 4–20 mm long 17

33. Monocarps one or two, sessile, two- to four-seeded; petals 4.0–8.5 mm long, provided with a small, incurved, tail-like, apical appendage; tropical South America Onychopetalum

34. Monocarps generally more numerous (up to 30), mostly distinctly stipitate, often one-seeded; petals 2.5–20.0 mm long, without apical appendage 18

35. Leaves asymmetrical; petals 2.5–4.5 mm long; monocarps one-seeded (except in B. pleiosperma), shortly stipitate; tropical South America Bocageopsis

36. Leaves symmetrical; petals mostly > 5 mm long; monocarps one- to several-seeded, mostly distinctly stipitate 19

37. Upper side of leaves with distinctly grooved midrib; from Costa Rica in the north to Bolivia in the south, eastwards up to the Guianas, and south of the Amazon River Cremastosperma

38. Upper side of leaves with non-grooved midrib 20

39. Leaves with distinctly raised veins on both sides; petals 10–15 mm long; seeds 25–30 mm long; Amazonian south-west Venezuela and adjacent Brazil Pseudephedranthus

40. Leaves with veins on upper side (except for raised midrib) not or indistinctly raised; petals 4–10 mm long; seeds 8–20 mm long 21

41. Inflorescences often one-flowered and shortly pedicellate, flower stalk densely beset with 3–6 bracts; apical prolongation of connective tongue-shaped; monocarps one-seeded; throughout Neotropics Oxandra

42. Inflorescences often branched, if one-flowered, flower stalk not densely beset with bracts; apical prolongation of connective discoid; monocarps one- to several-seeded; seeds striate to pitted; from Mexico (Oaxaca) in the north to Bolivia, north Paraguay, and southern Brazil in the south Unonopsis

43. Bracts absent 23

44. Bracts present 29

45. Flowers pendent on long (40–60 mm) pedicels; inner petals boat-shaped; throughout Neotropics, except for West Indies Cymbopetalum

46. Flowers non-pendent and pedicels much shorter; inner petals not boat-shaped 24

47. Leaves asymmetrical; monocarps 20–90 × 30–40 mm, thick-walled (wall 2.5–4.0 mm thick); from Costa Rica in the north through western South America to Bolivia, and south-east Brazil Porcelia

48. Leaves symmetrical; monocarps smaller, thin-walled 25

49. Petals basally connate 26

50. Petals free 27

51. Petals basally connate into 2–4 mm long tube; monocarps dehiscent, falciform, yellow or orange; aril fleshy, two-lobed; tropical South America Cardiopetalum

52. Petals free; monocarps indehiscent, fusiform to linear, green; aril fibrous; western South America Froesiodendron

53. Leaves often triplinerved at base; monocarps three to nine; flower buds globose; stamens c. 40; tropical South America, absent from central Amazon basin Trigynaea

54. Leaves not triplinerved at base; monocarps one to three; flower buds globose or conical; stamens < 20; east and south-east Brazil 28

55. Flower buds conical; petals linear, recurved to patent; calyx cup-shaped, without distinct lobes; flowers solitary or in many-flowered inflorescences; inflorescences often flagellate and produced from main stem; east and south-east Brazil. Hornschuchia

56. Flower buds globose; petals ovate to elliptic, erect; calyx distinctly three-lobed; flowers solitary; east and south-east Brazil Bocagea

57. Upper side of leaves with raised midrib 30

58. Upper side of leaves with impressed to flat midrib 31

59. Fruit apocarpous, monocarps distinctly stipitate; seeds pitted; sepals < 5 mm long; inner base of inner petals with food bodies; from Mexico in the north to Bolivia in the south Mosannona

60. Fruit syncarpous, carpels strongly coherent; seeds smooth; sepals > 9 mm long; petals without food bodies; Amazonian Brazil (Upper Rio Negro) Duckeanthus

61. Flowers winged; fruit syncarpous (rarely apocarpous); throughout Neotropics and Africa Annona

62. Flowers not winged; fruit apocarpous or syncarpous 32

63. Outermost stamens staminodal; fruit syncarpous with almost woody basal collar; tropical South America Fusaea

64. All stamens fertile; fruit apocarpous or syncarpous, without basal collar 33

65. Fruit syncarpous, each carpel one-seeded; petals often thick and fleshy; throughout Neotropics Annona

66. Fruit apocarpous, each monocarp one- to several-seeded; petals thin 34

67. Pedicels often with one leafy bract; Mexico and Central America and adjacent northern Colombia Desmopsis

68. Pedicels without leafy bracts 35

69. Monocarps one-seeded; petals yellow to cream, margins ciliate; from Panama in the north to Peru in the south, also one species in south-east Brazil (Bahia) Malmea

70. Monocarps one- to several-seeded; petals red, purple, brown, or rarely cream, margins not ciliate 36

71. Petals distinctly veined, length/width ratio 2–5; flowers often with a foetid scent; monocarps 13–100 mm long; seeds with lamellate rumination; Mexico and Central America Sapranthus

72. Petals not distinctly veined, length/width ratio 5–20; flowers without a foetid scent; monocarps 10–30 mm long; seeds with spiniform rumination; Mexico, Central America to Pacific coast of Colombia Stenanona

Key to african and malagasy genera of annonaceae (Thomas L. P. Couvreur & David M. Johnson)

1. Indument of stellate or scale-like hairs (easily visible with a hand lens) 2

2. Indument of simple hairs or lacking 7

3. Lower surface of leaf completely covered with silver scale-like hairs; West and Central Africa Meiocarpidium

4. Indument of lower leaf surface sparser, not completely covering surface; hairs more stellate than scale-like 3

5. Outer petal whorl absent; monocarps stipitate, stipe articulated at apex; West and central Africa, one species in East Africa Annickia

6. Outer petal whorl present; monocarps sessile, or if stipitate then stipe not articulated at apex 4

7. Trees; fruit syncarpous; West and Central Africa and Neotropics Duguetia

8. Scandent shrubs or lianas; fruit of one to many free monocarps 5

9. Carpel one; East Africa Dielsiothamnus

10. Carpels more than one 6

11. Inner petals smaller than outer ones; monocarps moniliform, with seeds in a single row; East Africa Friesodielsia (F. obovata)

12. Inner and outer petals subequal; monocarps oblong, with seeds in two rows; throughout tropical Africa, including Madagascar and Asia Uvaria

13. Lianas; inflorescence peduncle formed into a woody hook; throughout tropical Africa including Madagascar and Asia Artabotrys

14. Trees, shrubs or lianas; inflorescence peduncle not formed into a woody hook 8

15. Upper side of leaves with a raised midrib 9

16. Upper side of leaves with an impressed to flat midrib 11

17. Petals free; flower and fruit apocarpous, inner petals with brush-like structure on inner side; East Africa Ophrypetalum

18. Petals fused at base; flowers and fruit syncarpous 10

19. Corolla lobes equal in length, margins generally straight; throughout tropical Africa including Madagascar Isolona

20. Outer petals longer than inner, margins generally undulated or crisped; throughout tropical Africa Monodora

21. Calyx reduced and vestigial, present as basal flange (sometimes three-lobed); Madagascar Fenerivia

22. Calyx not reduced, clearly visible 12

23. Sepals free but enclosing petals until anthesis, sometimes reduplicate; monocarps multi-seeded 13

24. Sepals free but exceeded in length by petals well before anthesis, or sepals connate; monocarps one- or multi-seeded 16

25. Petals connate at base, crumpled in bud; throughout tropical Africa Hexalobus

26. Petals free to base, not crumpled in bud 14

27. Receptacle convex but not columnar; West and Central Africa Uvariastrum

28. Receptacle columnar 15

29. Small trees; anther connective reduced to a tuft of hairs; West and Central Africa Mischogyne

30. Scandent shrubs or lianas; anther connective flattened above anthers; Central and East Africa Toussaintia

31. Sepals completely connate 17

32. Sepals free, at least at the apex 18

33. Trees; calyx forming a flat disk at base of flower; petals six in a single whorl; West Africa Monocyclanthus

34. Lianas; calyx entirely enclosing flower in bud, tearing as flower enlarges; petals six in two whorls; Central Africa Letestudoxa

35. Flowers with two sepals; throughout tropical Africa Uvariopsis

36. Flowers with three sepals 19

37. Lianas with leaf-opposed or terminal inflorescences 20

38. Trees, or, if lianas, inflorescence axillary 26

39. Inner petals shorter than outer ones, vaulted and connivent over stamens and carpels 21

40. Inner and outer petals subequal, erect or spreading 23

41. Anthers septate; monocarps sessile; Cameroon Boutiquea

42. Anthers not septate; monocarps stipitate 22

43. Leaves glaucous beneath; inner petals with short claw; throughout tropical Africa Friesodielsia

44. Leaves sometimes pale beneath, but not glaucous; inner petals lacking claw; east Africa and Asia Sphaerocoryne

45. Monocarps sessile, forming a syncarpous fruit; Central Africa, Gabon Pseudartabotrys

46. Monocarps stipitate 24

47. Stamens usually < 15; monocarps often many-seeded and moniliform 25

48. Stamens numerous; monocarps one-(or two-)seeded; Democratic Republic of the Congo Afroguatteria

49. Petals connivent (or rarely imbricate) in bud; stamens obconical; throughout tropical Africa including Madagascar Monanthotaxis

50. Petals completely separate in bud; stamens linear; Democratic Republic of the Congo Gilbertiella

51. Flowers with three petals 27

52. Flowers with six petals 28

53. Petals opposite sepals, wood bright yellow, monocarps one-seeded; West and central Africa, one species in East Africa Annickia

54. Petals alternate with sepals, wood not bright yellow, monocarps multi-seeded; Central Africa Uvariopsis (U. tripetala)

55. Petals connate at base 29

56. Petals free 30

57. Young branches glabrous; flowers small (< 1 cm), carpels and monocarps solitary; Tanzania, Usambara Mountains Sanrafaelia

58. Young branches hairy; flowers large (> 2 cm), carpels and monocarps 5–20; East Africa Asteranthe

59. Monocarps stipitate, stipe articulated at apex 31

60. Monocarps sessile, or, if stipitate, stipe not articulated at apex 34

61. Inner petals shorter than outer ones 32

62. Inner and outer petals subequal 33

63. Anthers septate; monocarps one-seeded, with stipe longer than seed-containing portion; seeds smooth; West and Central Africa Neostenanthera

64. Anthers not septate; monocarps two-seeded, with stipe equal in length to or shorter than seed-containing portion; seeds tuberculate; West and Central Africa Cleistopholis

65. Petals linear, acute; introduced in Africa, South-East Asia Cananga

66. Petals ovate, obtuse; East Africa Lettowianthus

67. Inner petals much longer than outer ones; West and Central Africa Piptostigma

68. Inner petals shorter than or equal in length to outer petals 35

69. Fruits syncarpous 36

70. Fruits apocarpous 37

71. Flowers bisexual, borne in leaf-opposed and terminal inflorescences on leafy branches; throughout tropical Africa including Madagascar and Neotropics, introduced in Asia Annona

72. Flowers both staminate and bisexual, borne in long pendant leaf-opposed or axillary inflorescences on old branches or stems; West and Central Africa, one doubtful species in East Africa Anonidium

73. Inflorescences leaf-opposed, supra-axillary, or terminal 38

74. Inflorescences axillary, or plant cauliflorous 39

75. Flowers bisexual; petals ovate; anthers septate; monocarps fusiform, sessile; East Africa Mkilua

76. Androdioecious; petals linear; anthers non-septate; monocarps globose, stipitate; throughout tropical Africa Greenwayodendron

77. Anthers septate; monocarps dehiscent; throughout tropical Africa, Madagascar, Asia and the Neotropics Xylopia

78. Anthers non-septate; monocarps indehiscent 40

79. Inner petals smaller than outer ones, deeply concave; monocarps globose with up to 20 seeds in two rows; Central Africa Exellia

80. Inner and outer petals subequal, flat or concave; monocarps elongate, or if globose then containing only one or two seeds 41

81. Tertiary veins of leaves percurrent; androdioecious; monocarps elongate, seeds pitted; throughout tropical Africa Polyceratocarpus

82. Tertiary veins variously curved and anastomosing; flowers bisexual; monocarps elongate or globose; seeds pitted or smooth 42

83. Petals < 5 mm long 43

84. Petals ≥ 10 mm long 44

85. Flowers borne singly on leafless branches; monocarps stipitate, one-seeded; East Africa Cleistochlamys

86. Flowers multiple in cymose inflorescences; monocarps sessile, two-seeded; Madagascar Ambavia

87. Monocarps long-stipitate, one-seeded, red; East Africa, including Madagascar and Asia Polyalthia

88. Monocarps sessile, multi-seeded, green or brown 45

89. Carpels 4, ovules and seeds uniseriate; Tanzania, Kimboza Forest Reserve Mwasumbia

90. Carpels > 20, ovules and seeds biseriate; throughout tropical Africa Uvariodendron

Key to asian and australasian genera of annonaceae (Svenja Meinke & Paul J. A. Keßler)

1. Lianas 2

2. Trees or shrubs 10

3. Indument of stellate hairs (easily visible with a hand lens); throughout tropical Australasia and (for Uvaria) tropical Africa including Madagascar Uvaria

4. Indument of simple hairs or glabrous 3

5. Inflorescence peduncle formed into a woody hook; throughout tropical Australasia and tropical Africa including Madagascar Artabotrys

6. Inflorescence peduncle not formed into a woody hook 4

7. Inflorescences supra-axillary or leaf opposed 5

8. Inflorescences axillary 7

9. Flowers in multiflowered inflorescences; stamen connective tongue-shaped/acute; throughout tropical Asia Fissistigma

10. Flowers solitary or in one-flowered inflorescences; stamen connective discoid (uvarioid) 6

11. Petals coherent above sexual organs; throughout tropical Asia Friesodielsia

12. Petals not coherent above sexual organs; throughout tropical Australasia Desmos

13. Petals coherent above sexual organs 8

14. Petals not coherent above sexual organs 9

15. Petals clawed; stamen connective tongue-shaped/acute; New Guinea Schefferomitra

16. Petals not clawed; stamen connective discoid (uvarioid); tropical West Asia Sphaerocoryne p.p./Melodorum p.p.

17. Sepals persisting in fruit; carpels few (10–15); ovules three to five; monocarps globose, < 1 cm in diameter; tropical Australasia except India Mitrella

18. Sepals not persisting in fruit; carpels six; ovules six or more; monocarps cylindrical, > 2 cm in diameter; Thailand, Malesia Pyramidanthe

19. Flowers in multiflowered inflorescences 11

20. Flowers solitary or in one-flowered inflorescences 19

21. Petals coherent above sexual organs 12

22. Petals not coherent above sexual organs 16

23. Inner petals longer than outer ones 13

24. Inner petals shorter than or equal in length to outer ones 14

25. Stamen connective not prolonged (miliusoid); stamens few (three to 12); throughout tropical Asia Orophea

26. Stamen connective discoid (uvarioid); stamens many (> 30); throughout tropical Australasia Pseuduvaria

27. Petals clawed; ovule one; seed one; tropical Asia except India Neo-uvaria

28. Petals not clawed; ovules two to many; seeds two to many 15

29. Midrib on upper surface of leaf raised; carpel one; throughout tropical Asia Cyathocalyx

30. Midrib on upper surface of leaf flat/impressed; carpels few (two to 20); throughout tropical Asia Drepananthus

31. Flowers unisexual, with carpellate inflorescences at base of main trunk; West Malesia Stelechocarpus

32. Flowers bisexual 17

33. Stamens many (> 30); carpels many (> 20); throughout tropical Asia Maasia

34. Stamens few (< 20); carpel one 18

35. Trees up to 30 m tall; sepals and petals valvate; West Malesia Mezzettia

36. Treelets up to 5 m tall; sepals and petals imbricate; West Malesia Dendrokingstonia

37. Sepals imbricate 20

38. Sepals valvate 21

39. Inner petals shorter than outer ones; tropical Asia except New Guinea Sageraea

40. Inner and outer petals subequal in length; throughout tropical Asia except New Guinea Enicosanthum

41. Petals in one whorl 22

42. Petals in two whorls 23

43. Petals three; anthers not septate, with pollen in monads; monocarps without abscission zone between seed bearing part and stalk (without a stipe); throughout tropical Asia except New Guinea Dasymaschalon

44. Petals four to nine; anthers septate, pollen in polyads; monocarps with abscission zone between seed bearing part and stalk (with a stipe); South China to Sumatra and Borneo Disepalum

45. Anthers septate, with pollen in tetrads or polyads 24

46. Anthers not septate, with pollen in monads 28

47. Inner petals coherent above sexual organs 25

48. Inner petals not coherent above sexual organs 27

49. Inner petals spoon-shaped; throughout tropical Asia, Africa and Neotropics Xylopia

50. Inner petals clawed 26

51. Inflorescences leaf-opposed; throughout tropical Asia Mitrephora

52. Inflorescences axillary to slightly supra-axillary or plant cauliflorous; throughout tropical Australasia Goniothalamus

53. Fruits syncarpous; without abscission zone between seed bearing part and stalk (without a stipe); cultivated for its fruits; Neotropics and Africa, introduced throughout tropical Australasia Annona

54. Monocarps not connate, with abscission zone between seed bearing part and stalk (with a stipe); cultivated for its flowers; throughout tropical Australasia, introduced in Africa Cananga

55. Ovules three to many 29

56. Ovule(s) one or two 33

57. Petals coherent above sexual organs 30

58. Petals not coherent above sexual organs 31

59. Sepals free; throughout tropical Asia, except New Guinea Meiogyne

60. Sepals connate; South Thailand and West Malesia Platymitra

61. Petals saccate; stamen connectives not prolonged (miliusoid); throughout tropical Asia Alphonsea

62. Petals not saccate; stamen connectives discoid (uvarioid) 32

63. Inflorescences axillary; ovules three to five; tropical Australia Meiogyne (ex Fitzalania)

64. Inflorescences supra-axillary; ovules about 10; West Malesia except Philippines Monocarpia

65. Petals clawed 34

66. Petals not clawed. 35

67. Petals coherent above sexual organs; carpels few (< 20); throughout tropical Australasia Popowia

68. Petals not coherent above sexual organs; carpels many (> 20); West Malesia Trivalvaria

69. Petals connate 36

70. Petals free 37

71. Petals coherent above sexual organs; ovules two; Philippines, East Malesia, tropical Australia Haplostichanthus

72. Petals not coherent above sexual organs; ovule one; Borneo Woodiellantha

73. Inner petals longer than outer ones 38

74. Inner petals shorter than or equal in length to outer ones 40

75. Inflorescences axillary; ovules two; throughout tropical Australasia Miliusa

76. Inflorescences supra-axillary or leaf-opposed; ovule one 39

77. Petals coherent above sexual organs; tropical West Asia Marsypopetalum

78. Petals not coherent above sexual organs; throughout tropical Asia Phaeanthus

79. Stamens few (≤ nine); Sri Lanka Phoenicanthus

80. Stamens many (> 30) 41

81. Petals spoon-shaped; monocarps dehiscent; throughout tropical Asia, except New Guinea, and throughout Neotropics Anaxagorea

82. Petals not spoon-shaped; monocarps indehiscent 42

83. Petals coherent above sexual organs; Thailand, Indochina Melodorum p.p./Sphaerocoryne p.p.

84. Petals not coherent above sexual organs; throughout tropical Australasia Polyalthia

ACKNOWLEDGEMENTS

The authors would like to thank Thierry Derion, Lars Chatrou and four anonymous reviewers for their comments and improvements to the keys and text. Richard Saunders is thanked for significantly improving the present article and for sharing his insights about the status of the name Oncodostigma.