1. Ovules naked, borne on a floral axis without carpels, or on open carpels without a stigma. Perianth simple or none. Flowers unisexual. Stem
woody. [Subdivision GYMNOSPERMAE.]  2

Ovules encased in the ovary formed by stigma-bearing carpels and nearly always closed to the top, rarely (Resedaceae) open above. [Subdivision
ANGIOSPERMAE.]   5

2. Leaves pinnately compound or dissected, forming a crown at the top of the stem. Stem simple or scantily branched towards the top. Juice mucilaginous. Perianth none. Stamens with numerous pollen-sacs. Embryo with 2 more or less connate cotyledons. [Class CYCADALES.]  1. Cycadaceae.

Leaves undivided, scattered along the branches of the stem, rarely (Gnetaceae) leaves 2, arising from the top of an undivided turnip-shaped stem and sometimes splitting lengthwise. Stamens with 1-9 pollen-sacs.
Embryo with 2-15 free cotyledons  3

3. Perianth present. Juice not resinous. Leaves not needle-shaped. Shrubs.
[Class GNETALES.]  4. Gnetaceae.

Perianth absent. Juice resinous, rarely scarcely so, but then leaves needle-shaped.
Leaves needle- or scale-shaped. [Class CONIFERAE.]  4

4. Seeds overtopping the fleshy or rudimentary carpels and surrounded by a fleshy aril. Carpels with 1 ovule  2. Taxaceae.

Seeds concealed between the carpels, without an aril. Carpels usually with
2 or more ovules  3. Pinaceae.

5. (1.) Embryo with a single cotyledon, rarely undivided. Vascular bundles scattered in the stem. Leaves usually parallel-veined (net-veined in many Araceae Dioscoreaceae and Taccaceae and a few Hydrocharitaceae
Liliaceae and Orchidaceae), generally narrow entire and sessile with a dilated base. Flowers usually 3-merous. [Class MONOCOTYLEDONEAE.]  6

Embryo with 2 cotyledons, rarely with only one well-developed cotyledon or undivided. Vascular bundles of the stem nearly always disposed in
a cylinder. Leaves usually net-veined, rarely sessile with a dilated base and a narrow entire blade. Flowers usually 4- or 5-merous. [Class
DICOTYLEDONEAE.]  52

6. Perianth wanting or rudimentary, that is, reduced to small, hypogynous, free or partially-united scales, rarely (Potamogetonaceae) replaced by sepaloid appendages of the connective.  7

Perianth well developed, calyx- or corolla-like or consisting of calyx and corolla, rarely (Eriocaulaceae and Restionaceae) wanting in the female flowers.  15

7. Flowers in the axils of membranous or more or less dry bracts (glumes) in spikelets consisting of one or several flowers and one or several empty glumes and nearly always arranged in spikes, racemes, panicles, or heads.
Land-, marsh-, or freshwater-plants. Carpel solitary, with a single basal or laterally attached ovule  8

Flowers in spadices with a fleshy rachis and surrounded by one or several spathes, more rarely solitary or in glomerules, heads, or spikes; in the latter case (Potamogetonaceae) saltwater  9

8. Embryo enclosed in the lower part of the albumen. Seed and ovule attached at the base, free from the pericarp and the wall of the ovary. Style 1, with 1-3 stigmas. Anthers usually affixed at the base. Sheaths of the cauline and inner radical leaves closed all round, usually without a ligule. Stem usually triangular solid and without nodes.  17. Cyperaceae.

Embryo outside the albumen, at its base. Seed and ovule attached laterally, but often near the base, usually adnate to the pericarp or the wall of the ovary. Style 1, with 1-6 stigmas, or styles 2. Anthers usually affixed at the back. Sheaths of the leaves nearly always split on one side and ending in a ligule. Stem usually cylindrical and hollow between the nodes.  16. Gramineae.

9. Plants without differentiation into stem and leaves, consisting of small floating leaf- or granule-like shoots. Flowers 2-3 together in cavities of the shoots  20. Lemnaceae.

Plants differentiated into stem and leaves  10

10. Flowers solitary or in glomerules in the axils of the leaves. Carpel solitary. Naias, 9. Naiadaceae.

Flowers in spikes, spadices, or heads, rarely (Potamogetonaceae) solitary or in glomerules, but then several separate carpels  11

11. Male flowers in panicles, female in heads or spadices. Flowers dioecious.
Leaves narrow, usually serrate or prickly. Stem usually woody. Pandanus, 6. Pandanaceae.

Male or all flowers solitary or in spikes, heads, or cymes  12

12. Flowers in globose heads Sparganium, 7. Sparganiaceae.

Flowers solitary or in spikes, spadices, or cymes  13

13. Ovaries several, separate, rarely ovary solitary, and then marine plants, very rarely freshwater-plants with hermaphrodite flowers. If flowers in spadices or spikes, then hermaphrodite or polygamous with 1 or several one-ovuled ovaries  8. Potamogetonaceae.

Ovary solitary. Land-, marsh-, or freshwater-plants; the latter with unisexual flowers. Flowers in spadices, unisexual, rarely hermaphrodite, but then with a several-ovuled ovary.  14

14. Flowers monoecious; male inflorescence, at least when young, separated from the female by a deciduous spathe. Flowers usually surrounded by hairs. Ovule 1, pendulous. Seed-coat not fleshy. Typha, 5. Typhaceae.

Flowers hermaphrodite or unisexual; if monoecious, then male inflorescence in uninterrupted connexion with the female, or separated from it by an empty interval or by barren flowers, but not by a spathe. Seed-coat fleshy.  19. Araceae.

15. (6.) Ovary superior.  16

Ovary inferior or half-inferior.  37

16. Carpel solitary or carpels connate and forming a single entire or slightly lobed ovary.  17

Carpels several, separate or cohering only at the base.  33

17. Perianth calyx-like, sometimes slightly coloured, but firmly membranous or leathery, or differentiated by size or coalescence into an inner and an outer whorl of segments, all of which are sepaloid.  18

Perianth corolla-like or consisting of outer sepaloid and inner petaloid segments.  25

18. Leaves folded in the bud, subsequently splitting into pinnately or palmately disposed segments, rarely only 2-cleft. Stem woody, but sometimes very short. Flowers in spadices or panicles with spathes.  18. Palmae.

Leaves undivided, rarely divided, but then not folded and springing from a herbaceous stem.  19

19. Flowers in spadices with a spathe forming sometimes a continuation of the stem.  19. Araceae.

Flowers not in spadices.  20

20. Stamen 1. Ovule 1, erect. Stigmas several. Flowers solitary or in glomerules in the axils of the leaves. Naias, 9. Naiadaceae.

Stamens 2-6.  21

21. Anthers turned outwards. Ovary with 1 ascending ovule in each cell and with several sessile stigmas. Flowers hermaphrodite. Seeds exalbuminous. Triglochin, 11. Scheuchzeriaceae.

Anthers turned inwards. Seeds albuminous.  22

22. Anthers 1-celled. Flowers unisexual, in spikelets usually arranged in spikes or panicles. Perianth dry. Stamens 2-3. Ovary with 1 pendulous ovule in each cell.  22. Restionaceae.

Anthers 2-celled. If flowers unisexual and in spikelets, then perianth not dry.  23

23. Flowers monoecious, in heads surrounded by an involucre. Ovary with
1 pendulous ovule in each cell.  25. Eriocaulaceae.

Flowers hermaphrodite, polygamous, or dioecious.  24

24. Style 1 with 3 long and thin stigmas. Perianth dry. Leaves linear.  31. Juncaceae.

Style 1 with 3 thick or short stigmas or with a single stigma, or styles 3.
Perianth usually herbaceous.  32. Liliaceae.

25. (17.) Perianth corolla-like. Usually ovules inverted and embryo or its radicle placed next to the hilum, more rarely ovules straight and embryo or its radicle remote from the hilum, and then albumen fleshy or cartilaginous.  26

Perianth differentiated into calyx and corolla. Ovules straight. Embryo small, remote from the hilum. Albumen more or less mealy.  31

26. Seeds with mealy albumen.  27

Seeds with fleshy or cartilaginous albumen.  29

27. Ovules 2 or more in each ovary-cell. Seeds with a large embryo enclosed in the albumen.  29. Pontederiaceae.

Ovule 1 in each ovary-cell. Seeds with a small embryo appressed to the albumen. Perianth white or yellow.  28

28. Perianth-segments free or nearly so. Anthers opening lengthwise. Stigmas
3. Fruit a berry. Stem climbing. Leaves scattered, ending in tendrils. Flowers in panicles. Flagellaria, 21. Flagellariaceae.

Perianth-segments united below into a tube. Anthers opening by apical pores. Stigma 1. Fruit a capsule. Stem erect. Leaves all radical.
Flowers in heads. Maschalocephalus, 26. Rapateaceae.

29. Stamens 3. Ovule 1 in each ovary-cell. Perianth yellow.  33. Haemodoraceae.

Stamens 6 or more, rarely 3, but then ovules 2 or more in each ovary-cell.  30

30. Anthers opening at the apex. Stamens affixed to the perianth. Ovary adnate to the perianth at the base. Ovules numerous in each cell.
Perianth blue. Leaves linear or lanceolate. Walleria, 34. Amaryllidaceae.

Anthers opening lengthwise, rarely at the apex, but then stamens (at least some of them) and ovary free from the perianth.  32. Liliaceae.

31. (25.) Ovary 2-3-celled. Fertile stamens 2-6.  28. Commelinaceae.

Ovary 1-celled, sometimes with incomplete partitions. Ovules numerous.
Fertile stamens 3. Flowers in heads, short spikes, or umbels.  32

32. Sepals 3, subequal. Anthers opening by a terminal lid. Staminodes none.
Stigma 1. Leaves scattered. Flowers in umbels. Mayaca, 23. Mayacaceae.

Sepals 3, very unequal, or 2. Anthers opening by longitudinal slits. Staminodes
3. Stigmas 3. Leaves all radical. Flowers in heads or spikes. Xyris, 24. Xyridaceae.

33. (16.) Leaves divided. Woody plants. Seeds albuminous.  18. Palmae.

Leaves undivided. Herbaceous plants.  34

34. Plants without green colour, growing upon mould. Leaves reduced to scales.
Perianth of 6 petaloid segments. Seeds albuminous. Sciaphila, 15. Triuridaceae.

Plants of green colour, growing in the water. Leaves well developed.
Perianth of 6 segments differentiated into sepals and petals, or of 1-3
segments. Seeds exalbuminous.  35

35. Perianth consisting of 1-3 coloured segments. Aponogeton, 10. Aponogetonaceae.

Perianth consisting of 6 segments more or less distinctly differentiated into sepals and petals, rarely in the female flowers only of 3 greenish segments.  36

36. Ovules numerous, covering the whole inner surface of the carpels.  13. Butomaceae.

Ovules 1-2, rarely more, and then all inserted at the upper suture of the carpels.  12. Alismataceae.

37. (15.) Stamen 1. Flowers irregular.  38

Stamens 2-18. Flowers usually regular.  41

38. Staminodes small or wanting. Ovary 1-celled with numerous ovules.
Style adnate to the filament. Seeds exalbuminous. Leaves usually with longitudinal nervation.  44. Orchidaceae.

Staminodes, at least some of them, petal-like. Ovary 1-celled with a single ovule or more frequently 3-celled. Seeds albuminous. Leaves with pinnate nervation.  39

39. Anthers 2-celled. Sepals united below. Flowers symmetrical.  40. Zingiberaceae.

Anthers 1-celled. Sepals free. Flowers asymmetrical.  40

40. Ovules several or many in each ovary-cell. Seeds with straight embryo.
Leaf-stalk not thickened. Canna, 41. Cannaceae.

Ovules solitary in each cell. Seeds with curved embryo. Leaf-stalk thickened towards the apex or throughout its whole length.  42. Marantaceae.

41. Stamens 2-4, usually 3.  42

Stamens 5-18, usually 6.  45

42. Perianth-segments sepal-like or the outer sepal-, the inner petal-like. Ovary
1-celled, sometimes incompletely 6-celled. Seeds exalbuminous. Water plants.  14. Hydrocharitaceae.

Perianth-segments petal-like. Ovary usually 3-celled. Seeds albuminous.
Land- or marsh-plants.  43

43. Stamens opposite the outer perianth-segments. Anthers opening outwards or laterally.  38. Iridaceae.

Stamens alternating with the outer or with all perianth-segments. Anthers opening inwards or laterally.  44

44. Leaves well developed, green. Inner perianth-segments about equalling the outer. Anthers opening lengthwise. Stigmas 3, linear, or stigma single.  33. Haemodoraceae.

Leaves scale-like, not green, rarely well-developed and green, but then inner perianth-segments much smaller than the outer or wanting, anthers provided with an enlarged connective and opening transversely, and stigmas 3, short and thick.  43. Burmanniaceae.

45. Ovary incompletely 6-15-celled with 6-15 stigmas, more rarely completely
1-celled with 3 stigmas. Perianth consisting of calyx and corolla, more rarely only of 3 petal-like segments. Water-plants with submerged or floating leaves.  14. Hydrocharitaceae.

Ovary 3-celled, rarely 1-celled, but then stigmas 6. Perianth usually of 6 petaloid segments. Land-plants.  46

46. Ovary 1-celled. Style umbrella-shaped, 6-lobed. Tacca, 36. Taccaceae.
Ovary 3-celled.  47

47. Ovules in each ovary-cell 2, one above the other. Flowers unisexual, regular.
Stem climbing.  37. Dioscoreaceae.

Ovules in each ovary-cell 1, 2 side by side, or more. Flowers hermaphrodite, rarely unisexual but irregular.  48

48. Perianth distinctly differentiated into calyx and corolla. Leaves toothed.
Inflorescence spadix-like. Ananas, 27. Bromeliaceae.

Perianth more or less corolla-like.  49

49. Flowers distinctly irregular, in fascicles usually arranged in spikes or racemes.
Stamens 5, rarely 6. Seeds with more or less mealy albumen. Leaves with pinnate nervation. Tall plants.  39. Musaceae.

Flowers regular or nearly so. Stamens 6 or more. Seeds with fleshy or cartilaginous albumen. Leaves nearly always with longitudinal nervation.  50

50. Flowers solitary, terminal. No bulb or tuber; usually a short woody trunk.
Placentas much projecting, thickened, shield-shaped. Barbacenia, 35. Velloziaceae.

Flowers in umbels, spikes, racemes, or panicles, more rarely solitary, but then underground stem a bulb or a tuber. Placentas not much projecting and thickened.  51

51. Ovary half-inferior, with 2 basal ovules in each cell. Anthers opening at the apex. Seeds with a large embryo adjoining the albumen. Flowers in racemes or panicles. Cyanastrum, 30. Cyanastraceae.

Ovary inferior, rarely half-inferior, but then with more than two ovules in each cell. Seeds with a small embryo enclosed in the albumen.  34. Amaryllidaceae.

52. (5.) Perianth wanting or simple or consisting of a calyx and a choripetalous corolla; petals, if present, free, more rarely cohering at the apex or in the middle, but free at the base. [Subclass Archichlamydeae.]  53

Perianth consisting of a calyx and a sympetalous corolla; petals more or less united, at least at the base. [Subclass Metachlamydeae or
Sympetalae.]  551

53. Perianth wanting or simple, that is, consisting of similar segments, more rarely of 2-7 somewhat dissimilar ones without a distinct differentiation into sepals and petals. [Apetalae.]  54

Perianth differentiated into calyx and corolla, more rarely consisting of 8 or more slightly dissimilar segments not distinctly separated into sepals and petals. [Choripetalae.]  188

54. Perianth absent in the hermaphrodite and female flowers, but sometimes
replaced by bracteoles. Ovary naked.  55

Perianth present in the hermaphrodite and female flowers.  69

55. Ovary completely 1-celled.  56

Ovary 2-4-celled, at least in its lower half.  65

56. Ovule solitary, rarely (Balanophoraceae) ovules 3.  57

Ovules numerous, rarely (Casuarinaceae) 2.  63

57. Ovule basal or attached by a basal funicle.  58

Ovule apical or adnate to the wall of the ovary.  62

58. Ovule straight.  59

Ovule incurved or inverted.  61

59. Flowers in fascicles, the male with a perianth. Stamens 1-5. Stigma 1.
Fruit dry. Seed albuminous.  54. Urticaceae.

Flowers in spikes, the male without a perianth, but sometimes with 2-6 bracteoles. Stamens 2-12. Fruit succulent.  60

60. Flowers unisexual. Stigmas 2, thread-like. Fruit a drupe. Seed exalbuminous.
Trees, shrubs, or undershrubs. Leaves without stipules. Myrica, 48. Myricaceae.

Flowers hermaphrodite or polygamous, more rarely unisexual, but then leaves stipulate. Fruit a berry. Seed with copious albumen.  46. Piperaceae.

61. Ovule incurved. Stigmas 2-5. Seed with curved embryo. Flowers usually in glomerule-, or spike-like cymes.  67. Chenopodiaceae.

Ovule inverted. Stigmas 1-2. Seed with straight embryo. Flowers usually in heads.  226. Compositae.

62. Leaves well-developed, stipulate. Green plants. Ovule solitary, free.  53. Moraceae.

Leaves scale-like. Coloured (not green) herbaceous plants.  62. Balanophoraceae.

63. (56.) Ovules 2, ascending, straight. Male flowers with a 2-parted perianth.
Stamen 1. Fruit a nut. Trees or shrubs. Leaves whorled, scale-like.
Male flowers in spikes, female in heads. Casuarina, 45. Casuarinaceae.

Ovules numerous, inverted. Male flowers without a perianth, but sometimes with a disc. Fruit a capsule. Leaves well developed. Flowers in spikes or catkins.  64

64. Flowers with a disc sometimes replaced by scales. Stamens 2 or more.
Trees or shrubs. Leaves alternate, entire toothed or lobed, stipulate.  47. Salicaceae.

Flowers without a disc. Stamen 1 (or stamens 2 with united filaments.)
Aquatic herbs. Hydrostachys, 94. Hydrostachyaceae.

65. (55.) Ovary 2-celled at the base, with 1 ovule in each incomplete cell. Styles
2. Stamens 4. Trees or shrubs. Flowers in spikes or catkins.  50. Betulaceae.

Ovary completely 2-4-celled.  66

66. Ovules solitary in each ovary-cell.  67

Ovules 2 or more in each ovary-cell. Shrubs or trees. Leaves opposite.
Male flowers without a perianth.  68

67. Ovary 2-3-celled. Ovules with a double coat. 122. Euphorbiaceae.

Ovary 4-celled. Ovules with a single coat. Styles 2. Stamen 1. Male flowers without a perianth. Fruit a drupe. Herbs. Leaves opposite. Callitriche, 123. Callitrichaceae.

68. Ovary 2-celled with 2 ovules in each cell. Style 1, with 2 stigmas. Stamens
2. Fruit a nut. Leaves pinnate, exstipulate. Fraxinus, 197. Oleaceae.

Ovary 3-4-celled with numerous ovules in each cell. Styles 3-4. Stamens
3-8. Fruit a capsule or a schizocarp. Leaves undivided, stipulate. Myrothamnus, 99. Myrothamnaceae.

69. (54.) Ovary superior or nearly so.  70

Ovary inferior to half-inferior.  153

70. Ovary 1, entire or lobed.  71

Ovaries 2 or more, distinct or united at the base only.  146

71. Ovary 1-celled, sometimes incompletely chambered.  72

Ovary completely or almost completely 2- or more-celled.  118

72. Ovule 1.  73

Ovules 2 or more.  103

73. Ovule erect or ascending or attached by a basal funicle.  74

Ovule pendulous or descending.  94

74. Ovule straight.  75

Ovule incurved or inverted.  80

75. Style 1 or none; stigma solitary or stigmas 2 or more, contiguous at the base. Stamens 1-12.  76

Styles 2-4, free or united at the base; stigmas not contiguous at the base.
Stamens 4-50.  79

76. Flowers hermaphrodite or polygamous. Stigma sessile, 2-lobed. Seed with fleshy albumen. Shrubs or trees. Leaves without stipules. Exocarpus, 56. Santalaceae.

Flowers unisexual, rarely polygamous, but then herbs and stigma penicillate.  77

77. Leaves exstipulate. Stamens 2-12. Stigmas 2. Seed without albumen. Myrica, 48. Myricaceae.

Leaves stipulate, rarely exstipulate, but then stigma 1. Stamens 1-5.  78

78. Stamens straight in bud. Juice milky. Trees.  53. Moraceae.

Stamens incurved in bud. Juice not milky.  54. Urticaceae.

79. Leaves simple, entire toothed lobed or cleft, with a stem-clasping sheath at the base. Seed with copious mealy albumen.  66. Polygonaceae.

Leaves compound, exstipulate. Stamens 5. Seed without albumen. Pistacia, 127. Anacardiaceae.

80. (74.) Ovule incurved. Embryo distinctly curved; albumen usually mealy.  81

Ovule inverted. Embryo straight or nearly so; albumen usually fleshy
or wanting.  87

81. Perianth-segments 6, petal-like, free. Stamens 8-10. Style 3-4-cleft.
Flowers dioecious. Spiny trees. Didierea, 134. Sapindaceae.

Perianth-segments 1-5.  82

82. Perianth with valvate and folded aestivation, lobed, enlarged in fruit.
Stamens hypogynous, united at the base.  69. Nyctaginaceae.

Perianth with imbricate or open aestivation, rarely with valvate not folded aestivation; in the latter case deeply divided.  83

83. Stamens 1-10, perigynous, rarely (Queria) 10, hypogynous. Stipules present, rarely absent, and then leaves opposite and styles 2-3.  75. Caryophyllaceae.

Stamens 1-5, hypogynous or nearly so, rarely distinctly perigynous, but then stipules wanting and leaves alternate or style 1.  84

84. Stamens as many as the perianth-segments or one less (3-5), alternating with them, hypogynous. Flowers hermaphrodite.  85

Stamens as many as the perianth-segments or one less, but opposite to them, or considerably fewer, or in greater number. Leaves without stipules.  86

85. Flowers in cymes, 5-merous. Perianth membranous. Embryo hooked.
Leaves whorled, usually stipulate. Adenogramma, 72. Aizoaceae.

Flowers in spikes or racemes, with bracteoles. Perianth herbaceous.
Embryo nearly ring-shaped. Leaves alternate, usually exstipulate.  71. Phytolaccaceae.

86. Perianth more or less scarious or papery. Seed albuminous; embryo ring- or horseshoe-shaped. Flowers with bracteoles.  68. Amarantaceae.

Perianth more or less herbaceous or membranous. Stigmas 2-5.  67. Chenopodiaceae.

87. (80.) Leaves stipulate.  88

Leaves exstipulate.  89

88. Leaves opposite, undivided. Stamens 2-5. Seed albuminous.  75. Caryophyllaceae.

Leaves alternate. Seed exalbuminous.  103. Rosaceae.

89. Stem herbaceous. Flowers in heads, unisexual. Stamens as many as and alternate with the perianth-segments. Stigmas 2 in the female flowers. Seed exalbuminous.  226. Compositae.

Stem woody. Stigma 1.  90

90. Perianth with imbricate aestivation. Stamens numerous, free or nearly so. Seed exalbuminous. Calophyllum, 149. Guttiferae.

Perianth with valvate aestivation.  91

91. Stamens attached to the perianth, as many as its segments, 4, rarely 5; filaments free. Seed exalbuminous.  92

Stamens free from the perianth, as many as its segments or more often in greater number; filaments more or less united. Seed albuminous.  93

92. Stamens opposite the perianth-segments. Flowers in spikes or heads.  55. Proteaceae.

Stamens alternate with the perianth-segments. Flowers solitary or in fascicles. Elaeagnus, 172. Elaeagnaceae.

93. Stamens 5-15; filaments united at the base only. Anthers opening laterally. Perianth 5-toothed. Style slender. Seed without an aril; embryo large. Pisonia, 69. Nyctaginaceae.

Stamens very numerous or with the filaments united throughout their length. Anthers opening outwards. Perianth 2-4-, rarely 5-lobed.
Seed with an aril; embryo small.  82. Myristicaceae.

94. (73.) Ovule straight.  95

Ovule incurved or inverted.  96

95. Perianth 4-parted. Stamens 4. Seed without albumen. Shrubs or trees.
Flowers in spikes or heads.  55. Proteaceae.

Perianth 9-12-parted. Stamens 12-16. Seed with a thin albumen.
Herbs. Flowers solitary or in pairs in the axils of the leaves. Ceratophyllum, 77. Ceratophyllaceae.

96. Leaves stipulate.  97

Leaves exstipulate.  100

97. Leaves compound, but sometimes with one leaflet only. Ovary tightly enclosed by the perianth. Seed exalbuminous. Herbs, undershrubs, or shrubs.  103. Rosaceae.

Leaves simple, but sometimes (Moraceae) dissected.  98

98. Anthers 3-4-celled. Seed albuminous. Macaranga, 122. Euphorbiaceae.

Anthers 2-celled. Seed usually exalbuminous.  99

99. Flowers solitary or in fascicles. Stamens straight in the bud. Shrubs or trees. Juice not milky.  52. Ulmaceae.

Flowers in spikes, racemes, panicles, or heads, or inserted upon a dilated and often concave receptacle, rarely in fascicles, but then stamens bent inwards in the bud. Shrubs or trees with a milky juice or herbs.  53. Moraceae.

100. Anthers opening by valves. Perianth-segments 4 or 6. Seed without albumen. Trees or shrubs.  84. Lauraceae.

Anthers opening by longitudinal slits.  101

101. Stamens numerous. Flowers unisexual. Seed with copious fleshy albumen.
Trees or shrubs.  83. Monimiaceae.

Stamens 8-10.  102

102. Style simple. Seed with a straight embryo and a fleshy albumen or without albumen.  171. Thymelaeaceae.

Styles 2. Seed with a curved embryo and mealy albumen. Flowers in panicles. Galenia, 72. Aizoaceae.

103. (72.) Ovules basal or inserted upon a central placenta.  104

Ovules parietal or suspended from the apex of the cell.  108

104. Perianth of 2-3 minute scales. Ovules numerous, inserted upon a central placenta. Water-plants.  93. Podostemonaceae.

Perianth of 4-5 segments.  105

105. Flowers unisexual or polygamous, 4-merous. Ovules 2. Stigma 1.
Seeds without albumen; embryo straight. Shrubs. Leaves alternate. Empleurum, 115. Rutaceae.

Flowers hermaphrodite. Seeds with mealy albumen; embryo more or less curved. Usually herbs.  106

106. Leaves alternate. Stamens 5.  68. Amarantaceae.

Leaves opposite or whorled.  107

107. Stigma 1, rarely stigmas 2, and then ovules 2-4. Stamens 5 or more, perigynous.  72. Aizoaceae.

Stigmas 3-5, more rarely 2, but then ovules numerous or stamens 1-3.  75. Caryophyllaceae.

108. (103.) Ovules 2, suspended side by side from the apex of the cell or from
a central placenta. Fruit drupaceous, usually one-seeded.  109

Ovules 2, one above the other, or more than 2, affixed to one or more parietal placentas.  112

109. Stamens as many as, and alternate with the perianth-segments. Leaves exstipulate.  132. Icacinaceae.

Stamens as many as, and opposite the perianth-segments, or in greater number.  110

110. Flowers hermaphrodite. Leaves exstipulate.  59. Olacaceae.

Flowers unisexual. Leaves stipulate.  111

111. Stamens very numerous. Perianth 4-5-parted. Flowers fascicled. Guya, 159. Flacourtiaceae.

Stamens 2-8, rarely more, but then perianth 6-8-parted.  122. Euphorbiaceae.

112. Ovules 2 or more, attached to a single placenta. Stamens more or less perigynous. Fruit a legume. Leaves compound or reduced to the dilated foot-stalk, usually stipulate.  105. Leguminosae.

Ovules 3 or more, attached to 2 or more placentas, rarely to a single one, but then fruit a berry and leaves simple and undivided.  113

113. Style simple, or a sessile stigma.  114

Styles, style-branches, or sessile stigmas 2 or more.  116

114. Perianth-segments imbricate in bud. Stamens 10 or more. Ovary sessile. Seeds albuminous.  159. Flacourtiaceae.

Perianth-segments valvate in bud, more rarely imbricate, but then ovary stalked. Seeds exalbuminous.  115

115. Stamens more or less perigynous. Ovary sessile or short-stalked.
Perianth-segments valvate in bud. Leaves exstipulate. Seeds with straight embryo.  173. Lythraceae.

Stamens hypogynous, more rarely perigynous, but then ovary long-stalked and leaves stipulate. Seeds with curved embryo.  87. Capparidaceae.

116. Ovary at first open at the apex. Styles or sessile stigmas 3, free. Stamens
10-30. Perianth 5-6-cleft about halfway down. Seeds exalbuminous;
embryo curved. Ochradenus, 89. Resedaceae.

Ovary closed. Stamens 4 or more; if 10 or more, then perianth deeply divided.  117

117. Stamens as many as perianth-segments, 4-6, surrounded by a corona.
Styles 3, free or united at the base.  161. Passifloraceae.

Stamens more than perianth-segments, 6-40. Shrubs or trees.  159. Flacourtiaceae.

118. (71.) Ovules solitary in each ovary-cell.  119

Ovules 2 or more in each ovary-cell.  129

119. Ovules erect or ascending.  120

Ovules pendulous or descending.  124

120. Style 1, with 1-3 stigmas. Stamens inserted within the disc or at its edge. Flowers polygamous or unisexual. Seeds albuminous. Leaves pinnate, exstipulate.  134. Sapindaceae.

Styles 2-10, free or united below. Seeds albuminous, rarely exalbuminous, but then leaves stipulate. Leaves undivided or lobed.  121

121. Perianth-segments 3 or 6. Stamens 3. Flowers unisexual or polygamous.
Dwarf shrubs.  125. Empetraceae.

Perianth-segments 4-5. Stamens 4 or more.  122

122. Seeds with straight embryo. Fruit drupaceous. Styles 2-4, united below. Stamens 4-5, perigynous. Perianth valvate in bud. Shrubs.
Leaves stipulate, alternate.  137. Rhamnaceae.

Seeds with curved embryo and mealy albumen. Fruit dry, rarely baccate.
Herbs or undershrubs, rarely shrubs, but then leaves exstipulate.  123

123. Flowers solitary or in cymes. Herbs or undershrubs.  72. Aizoaceae.

Flowers in spikes or racemes.  71. Phytolaccaceae.

124. Stamens hypogynous.  125

Stamens perigynous.  127

125. Flowers hermaphrodite. Perianth-segments 4. Stamens 2, 4, or 6.
Ovary-cells 2. Seeds exalbuminous; embryo curved. Herbs. Leaves exstipulate. Lepidium, 88. Cruciferae.

Flowers unisexual, rarely hermaphrodite, but then perianth-segments 5, ovary-cells 5, and leaves stipulate.  126

126. Flowers unisexual. Leaves simple or palmately compound. Ovary usually 3-celled.  122. Euphorbiaceae.

Flowers hermaphrodite, rarely unisexual, but then leaves pinnate and ovary surrounded by large scales. Ovary 5-celled. Leaves compound, stipulate.  113. Zygophyllaceae.

127. Flowers unisexual or polygamous. Perianth of the male flowers consisting of calyx and corolla, that of the female and hermaphrodite flowers simple, valvate in bud. Stamens 5. Styles 2. Fruit capsular.
Embryo straight. Leaves stipulate. Trichocladus, 101. Hamamelidaceae.

Flowers hermaphrodite. Perianth simple. Leaves exstipulate.  128

128. Style and stigma simple. Embryo straight. Shrubs. Leaves alternate.  171. Thymelaeaceae.

Styles or stigmas 2-5. Embryo curved.  72. Aizoaceae.

129. (118.) Flowers unisexual or polygamous.  130

Flowers hermaphrodite.  136

130. Stamens 2. Ovary 2-celled with 2 ovules in each cell. Style 1, with 2 stigmas. Perianth 4-partite. Flowers polygamous. Leaves opposite, pinnate, exstipulate. Trees. Fraxinus, 197. Oleaceae.

Stamens 3 or more, rarely 2, but then flowers unisexual. Leaves simple or digitate, rarely pinnate, but then alternate.  131

131. Leaves with a pitcher-shaped appendage. Style absent; stigma 4-partite.
Ovary 4-celled with numerous ovules in each cell. Nepenthes, 91. Nepenthaceae.

Leaves without pitchers. Style present.  132

132. Style 1, with 2-6 stigmas. Seeds exalbuminous. Leaves alternate, without stipules.  134. Sapindaceae.

Styles 2 or more, free at the base, towards the apex, or throughout.  133

133. Perianth-segments valvate in bud, united below. Filaments united.  144. Sterculiaceae.

Perianth-segments imbricate or open in bud, rarely valvate, but then free and filaments also free.  134

134. Ovules with ventral raphe, 2 in a cell. Fruit usually opening septicidally and loculicidally. Leaves usually stipulate.  122. Euphorbiaceae.

Ovules with dorsal raphe. Shrubs or trees.  135

135. Flowers monoecious. Stamens 4-6. Ovary 3-celled with 2 ovules in each cell. Fruit a loculicidal capsule. Leaves opposite, without stipules.  124. Buxaceae.

Flowers dioecious or polygamous. Stamens 10 or more. Fruit a berry or a drupe. Leaves alternate.  159. Flacourtiaceae.

136. (129.) Perianth-segments free or nearly so. Stamens hypogynous or nearly so.  137

Perianth-segments evidently united. Stamens usually perigynous.  142

137. Stem herbaceous or woody at the base only.  138

Stem woody throughout its length.  140

138. Perianth-segments 2-3. Stamens 1-4. Water-plants.  93. Podostemonaceae.

Perianth-segments 4-5. Land-plants. Seeds with curved embryo.  139

139. Perianth-segments 4. Stamens 1-6. Ovary-cells 2. Style 1. Seeds exalbuminous. Leaves exstipulate.  88. Cruciferae.

Perianth-segments 5. Ovary-cells 3-7. Styles 3-7. Seeds albuminous.
Leaves stipulate.  72. Aizoaceae.

140. Ovary long-stalked. Perianth-segments 2-4, valvate or imbricate in bud; in the latter case stamens 4-8. Seeds exalbuminous; embryo curved.  87. Capparidaceae.

Ovary sessile or short-stalked. Stamens 10 or more. Seeds albuminous; embryo straight.  141

141. Perianth-segments 5, valvate in bud. Grewia, 141. Tiliaceae.

Perianth-segments; 3-8, imbricate or open in bud.  159. Flacourtiaceae.

142. (136.) Styles or sessile stigmas 2-5. Seeds albuminous; embryo curved.  72. Aizoaceae.

Style 1 or a sessile stigma. Seeds exalbuminous or with a straight embryo.  143

143. Stigmas or stigma-lobes 1-2. Ovules numerous in each ovary-cell.  144

Stigmas or stigma-lobes 4. Ovules 2-4 in each ovary-cell. Flowers
4-merous. Leaves opposite, stipulate.  145

144. Stamens 1-16. Ovary sessile or short-stalked. Embryo straight.
Leaves without stipules.  173. Lythraceae.

Stamens very numerous. Ovary long-stalked. Embryo curved. Leaves alternate, with small stipules. Maerua, 87. Capparidaceae.

145. Perianth with valvate aestivation. Stamens 4. Ovules ascending, at least the lower ones. Seeds exalbuminous.  169. Penaeaceae.

Perianth with imbricate aestivation. Stamens 8. Ovules pendulous.
Seeds albuminous. Geissoloma, 168. Geissolomataceae.

146. (70.) Ovules solitary in each carpel.  147

Ovules 2 or more in each carpel.  152

147. Ovules erect, incurved. Perianth regular, 4-5-parted. Seeds with a curved embryo and mealy albumen. Leaves undivided, without stipules.  148

Ovules pendulous or affixed laterally, rarely erect, but then perianth irregular and strap-shaped or surrounded by an epicalyx.  149

148. Flowers in spikes or racemes. Fruit succulent, baccate. Phytolacca, 71. Phytolaccaceae.

Flowers in cymes. Fruit dry.  72. Aizoaceae.

149. Perianth-segments free or nearly so. Stamens hypogynous.  150

Perianth-segments obviously united, at least in the female flowers. Stamens usually perigynous.  151

150. Flowers unisexual. Stamens as many as perianth-segments. Fruits fleshy, drupaceous.  80. Menispermaceae.

Flowers hermaphrodite or polygamous. Stamens usually more than perianth-segments. Fruits usually dry.  78. Ranunculaceae.

151. Leaves undivided, exstipulate. Shrubs or trees. Flowers unisexual.
Stamens 10 or more. Seeds with copious albumen.  83. Monimiaceae.

Leaves more or less deeply divided or compound, stipulate. Seeds without albumen.  103. Rosaceae.

152. Perianth of 6 free segments, imbricate in bud. Stamens numerous, free. Herbs. Leaves floating, peltate, exstipulate. Brasenia, 76. Nymphaeaceae.

Perianth 4-8-lobed, valvate in bud. Stamens 4 or more, united at the base. Trees. Leaves stipulate.  144. Sterculiaecae.

153. (69.) Ovary 1-celled.  154

Ovary, at least after fertilisation, completely or almost completely 2- or
more-celled.  177

154. Ovule 1.  155

Ovules 2 or more.  167

155. Ovule erect, ascending, attached by an erect funicle, or adnate to the ovary-wall.  156

Ovule pendulous or descending.  162

156. Ovule adnate to the ovary-wall. Style simple; stigma entire. Stamens as many as and opposite the perianth-segments. Perianth valvate in bud. Leaves without stipules. Shrubs growing upon trees.  61. Loranthaceae.

Ovary free from the ovary-wall. Trees or shrubs growing on the ground, or herbaceous plants.  157

157. Ovule straight. Embryo straight. Flowers unisexual. Stamens as many as and opposite the perianth-segments or more.  158

Ovule incurved or inverted. Embryo curved, more rarely straight, but then stamens as many as and alternating with the perianth-segments.  159

158. Stamens 1-5. Leaves simple or digitate, stipulate.  54. Urticaceae.

Stamens numerous. Stigmas 2. Trees. Leaves pinnate, exstipulate. Juglans, 49. Juglandaceae.

159. Ovule inverted. Stamens as many as and alternating with the perianth-segments.
Seeds exalbuminous; embryo straight.  226. Compositae.

Ovule incurved. Stamens as many as and opposite the perianth-segments or more. Seeds albuminous; embryo curved. Herbs.  160

160. Flowers unisexual. Perianth-segments 2-4, valvate in bud. Stamens
10-30. Stigma 1. Fruit drupaceous. Cynocrambe, 70. Cynocrambaceae.

Flowers hermaphrodite. Perianth-segments 5, imbricate in bud. Stamens
5. Stigmas 2-5. Fruit opening by a lid or bursting irregularly.  161

161. Style short, with long stigmas. Leaves alternate, exstipulate. Flowers in spike- or panicle-like inflorescences. Beta, 67. Chenopodiaceae.

Style long, with 2 short stigmas. Leaves opposite, linear, stipulate.
Flowers in heads. Sclerocephalus, 75. Caryophyllaceae.

162. (155.) Ovule straight. Style simple. Stamen 1. Flowers polygamous.
Reddish-brown herbs, parasitic upon roots. Leaves reduced to scales. Cynomorium, 184. Cynomoriaceae.

Ovule incurved or inverted. Green plants. Leaves well developed.  163

163. Flowers unisexual or polygamous. Stamens as many as and opposite the perianth-segments or fewer.  164

Flowers hermaphrodite. Stamens as many as and alternate with the perianth-segments or more. Leaves exstipulate.  166

164. Anthers opening by longitudinal slits. Flowers unisexual. Leaves stipulate.  53. Moraceae.

Anthers opening by valves. Leaves exstipulate.  165

165. Flowers unisexual. Leaves penninerved. Hypodaphnis, 84. Lauraceae.

Flowers polygamous. Leaves palminerved. Gyrocarpus, 85. Hernandiaceae.

166. Stamens 2. Styles 2. Embryo straight. Leaves radical. Gunnera, 183. Halorrhagaceae.

Stamens 3-5. Styles 4, or a single style. Embryo curved. Leaves alternate.  72. Aizoaceae.

167. (154.) Ovules 2-5.  168

Ovules numerous.  174

168. Ovules adnate to the ovary-wall. Stamens 2-6. Shrubs parasitic on the stem of trees.  61. Loranthaceae.

Ovules free from the ovary-wall. Plants growing on the ground or parasitic upon roots.  169

169. Ovules suspended from the apex of the ovary-cell. Stamens 8-10, rarely 4-5. Seeds exalbuminous. Shrubs or trees. Flowers in spikes, racemes, or heads.  179. Combretaceae.

Ovules inserted on a central, sometimes subparietal, placenta. Seeds albuminous.  170

170. Styles 4. Ovules 4. Stamens 4. Perianth of the male flowers consisting of calyx and corolla. Herbs or undershrubs. Laurembergia, 183. Halorrhagaceae.

Style 1. Perianth of all flowers simple.  171

171. Stigma 6-10-lobed. Stamens 5. Albumen ruminate. Shrubs or trees. Octoknema, 60. Octoknemataceae.

Stigma entire or 2-5-lobed.  172

172. Stamens 8, twice as many as the perianth-segments. Embryo with inferior radicle. Shrubs. Leaves opposite. Grubbia, 58. Grubbiaceae.

Stamens 2-6, as many as, or fewer than, the perianth-segments. Embryo with superior radicle or undivided.  173

173. Stem and leaves or scales green. Embryo with 2 cotyledons.  56. Santalaceae.

Stem and leaves not green; stem herbaceous; leaves scale-like. Flowers unisexual, in spikes or heads. Embryo without cotyledons.  62. Balanophoraceae.

174. (167.) Placentas apical. Style wanting. Stamens 3-4, united. Flowers hermaphrodite. Stem herbaceous, not green, bearing neither leaves nor scales. Hydnora, 65. Hydnoraceae.

Placentas parietal. Style present. Stem bearing leaves or scales.  175