| 1a. Foliage leaves all or principally basal; flower-stalk either completely leafless, or bearing a single pair of opposite leaves only. Bracts and scale-leaves are not considered foliage leaves — 2. | |
| 1b. Stem-leaves present on the stem, either one or more in number, and not limited to a single opposite pair — 3. | |
| 2a. Leaves compound — 7. | |
| 2b. Leaves simple — 18. | |
| 3a. Stem-leaves all or chiefly opposite or whorled (the bracts of the flower clusters may be alternate) — 4. | |
| 3b. Stem-leaves all or chiefly alternate — 5. | |
| 4a. Flowers small and inconspicuous, the perianth none or greenish or chaffy, and never petal-like in appearance — 50. | |
| 4b. Flowers with a white or colored petal-like perianth — 66. | |
| 5a. Flowers small and inconspicuous, without any white or colored petal-like perianth — 118. | |
| 5b. Flowers large or small, but with a white or colored petal-like perianth — 6. | |
| 6a. Flowers small, not exceeding 3 mm. in length or breadth — 144. | |
| 6b. Flowers larger, more than 3 mm. in length or breadth — 166. | |
| — 7— |
| 7a. Leaves twice to three times compound or dissected — 8. | |
| 7b. Leaves once-compound — 11. | |
| 8a. Flowers in racemes | 2b, in FUMARIACEAE, p. 41. |
| 8b. Flowers in umbels — 9. | |
| 9a. Flowers about 3 mm. wide, white or greenish-white — 10. | |
| 9b. Flowers 10-20 mm. wide, conspicuous | 45b, in RANUNCULACEAE, p. 39. |
| 10a. Leaflets 5-15 cm. long | 5b, in ARALIACEAE, p. 80. |
| 10b. Leaflets not over 2 cm. long | 16a, in UMBELLIFERAE, p. 81. |
| 11a. Leaflets 2 | 3a, in BERBERIDACEAE, p. 40. |
| 11b. Leaflets three or more — 12. | |
| 12a. Leaflets entire or very finely toothed — 13. | |
| 12b. Leaflets coarsely toothed or lobed — 15. | |
| 13a. Flowers irregular, in dense head-like umbels | 37a, in LEGUMINOSAE, p. 61. |
| 13b. Flowers consisting of a greenish or purplish bract wholly or partly enclosing a fleshy spike | 2, in ARACEAE, p. 8. |
| 13c. Flowers regular, solitary or in loose clusters — 14. |
| 14a. Leaflets reverse heart-shape, not over 2 cm. long | OXALIDACEAE, p. 64. |
| 14b. Leaflets 4-10 cm. long | 1c, in GENTIANACEAE, p. 88. |
| 15a. Flowers with colored or white petals and green or colored sepals — 16. |
| 15b. Flowers with one kind of perianth only (calyx), with broad and petal-like parts | 32, in RANUNCULACEAE, p. 38. |
| 15c. Flowers with white petal-like sepals and small inconspicuous petals | 38b, in RANUNCULACEAE, p. 39. |
| 16a. Petals and sepals each 4 | 31, in CRUCIFERAE, p. 44. |
| 16b. Petals and sepals each 5 or more — 17. |
| 17a. Leaves with stipules | ROSACEAE, p. 51. |
| 17b. Leaves without stipules | 23b, in RANUNCULACEAE, p. 37. |
| — 18— |
| 18a. Stem-leaves a single opposite pair (basal leaves may also be present) — 19. | |
| 18b. Stem-leaves none — 23. | |
| 19a. Leaves entire — 20. | |
| 19b. Leaves toothed or lobed — 21. | |
| 20a. Flowers solitary; leaves broadly kidney-shape | ARISTOLOCHIACEAE, p. 25. |
| 20b. Flowers in racemes; leaves linear or lanceolate | PORTULACACEAE, p. 34. |
| 21a. Flowers in racemes; petals deeply toothed | 23b, in SAXIFRAGACEAE, p. 51. |
| 21b. Flowers solitary or few in a cluster; petals entire or nearly so — 22. | |
| 22a. Petals 5 | GERANIACEAE, p. 64. |
| 22b. Petals 6 or more | 2b, in BERBERIDACEAE, p.40. |
| 23a. Flowers or flower-clusters sessile, at or partly beneath the surface of the ground | 4a, in ARACEAE, p. 8. |
| 23b. Flowers or flower-heads solitary at the ends of the flower-stalks — 24. | |
| 23b. Flowers or flower-heads numerous or several on each flower-stalk — 38. | |
| 24a. Flowers yellow — 25. | |
| 24b. Flowers not yellow — 29. | |
| 25a. Juice milky | 16, in COMPOSITAE, p. 115. |
| 25b. Juice not milky — 26. | |
| 26a. Aquatic or mud plants, with large entire leaves 1-4 dm. wide | NYMPHAEACEAE, p. 35. |
| 26b. Land plants, with smaller or lobed leaves — 27. | |
| 27a. Flower-stalk scaly | 110, in COMPOSITAE, p. 122. |
| 27b. Flower-stalk bare or with 1 to 2 minute bracts — 28. | |
| 28a. Flowers regular | 10, in RANUNCULACEAE, p. 36. |
| 28b. Flowers irregular, with a spur | 3a, in VIOLACEAE, p. 75. |
| 29a. Flowers obviously irregular, with a spur — 30. | |
| 29b. Flowers regular or nearly so, without a spur — 31. | |
| 30a. Leaves sessile or nearly so; stamens 2 | LENTIBULARIACEAE, p. 105. |
| 30b. Leaves petioled; stamens 5 | VIOLACEAE, p. 75. |
| 31a. Flowers 3 mm. wide or smaller; leaves thread-like | 16a, in SCROPHULARIACEAE, p. 103. |
| 31b. Flowers 6 mm. wide or larger — 32. | |
| 32a. Ovary 1 — 33. | |
| 32b. Ovaries numerous — 37. | |
| 33a. Leaves lobed or cleft — 34. | |
| 33b. Leaves entire or toothed — 35. | |
| 34a. Leaves deeply 2-cleft; stamens 8 | 3a, in BERBERIDACEAE, p. 40. |
| 34b. Leaf 1, palmately lobed; stamens numerous | 1a, in PAPAVERACEAE, p. 41. |
| 35a. Flowers dull red | ARISTOLOCHIACEAE, p. 25. |
| 35b. Flowers white or pinkish — 36. | |
| 36a. Leaves entire; stamens with good anthers 5 | 13, in SAXIFRAGACEAE, p. 50. |
| 36b. Leaves minutely toothed; stamens 8-10 | 14a, in ERICACEAE, p. 85. |
| 37a. Leaves lobed or divided | RANUNCULACEAE, p. 35. |
| 37b. Leaves crenate or toothed | 64a, in ROSACEAE, p. 56. |
| — 38— |
| 38a. Flowers of the composite type, with several or many small flowerets closely aggregated into a dense head surrounded by a calyx-like involucre of small bracts | 10, in COMPOSITAE. p. 114. |
| 38b. Flowers separate; variously clustered, but never crowded into involucred heads — 39. | |
| 39a. Flowers in dense close spikes — 40. | |
| 39b. Flowers in open loose clusters — 42. | |
| 40a. Flower-stalk leafless below the spike | PLANTAGINACEAE, p. 107. |
| 40b. Flower-stalk with several bracts — 41. | |
| 41a. Leaves entire | 9c, in ORCHIDACEAE, p. 16. |
| 41b. Leaves toothed | 6a, in SCROPHULARIACEAE, p. 102. |
| 42a. Flowers in umbels — 43. | |
| 42b. Flowers in racemes, panicles, flat-topped clusters, or merely 1 or 2 — 45. | |
| 43a. Leaves almost round, peltate, palmately veined | 3a, in UMBELLIFERAE, p. 80. |
| 43b. Leaves at least twice as long as broad, with a single mid-vein — 44. | |
| 44a. Stamens 5 | PRIMULACEAE, p. 87. |
| 44b. Stamens 10 | 15, in ERICACEAE, p. 85. |
| 45a. Leaves cylindrical, hollow, obtuse. | 1a, in LOBELIACEAE, p. 113. |
| 45b. Leaves beset on the upper side with long glandular hairs; bog plant with flowers in racemes | DROSERACEAE, p. 48. |
| 45c. Leaves flat, pubescent or smooth, but not with long glandular hairs — 46. | |
| 46a. Sepals and petals each 4 | 53, in CRUCIFERAE, p. 46. |
| 46b. Sepals and petals each 5 — 47. | |
| 46c. Sepals 6; petals none; flowers minute, green; leaves frequently lobed at the base | 4, in POLYGONACEAE, p. 25. |
| 47a. Petals united with each other in an irregular corolla | LENTIBULARIACEAE, p. 105. |
| 47b. Petals separate from each other — 48. | |
| 48a. Stamens 10; style 1 | ERICACEAE, p. 84. |
| 48b. Stamens 5 or 10; styles 2 | SAXIFRAGACEAE, p. 49. |
| 48c. Stamens and pistils each very numerous — 49. | |
| 49a. Flowers white | 64a, in ROSACEAE, p. 56. |
| 49b. Flowers yellow | 13a, in RANUNCULACEAE, p. 36. |
| — 50— |
| 50a. Leaves compound or deeply lobed — 51. | |
| 50b. Leaves entire or toothed — 54. | |
| 51a. Flowers in axillary racemes, spikes, or panicles | URTICACEAE, p. 23. |
| 51b. Flowers terminal, or in terminal clusters — 52. | |
| 52a. Flowers in umbels; leaves palmately compound | ARALIACEAE, p. 80. |
| 52b. Flowers in racemes or spikes, or solitary — 53. | |
| 53a. Leaves deeply pinnatifid; swamp plants with flowers in spikes or solitary | HALORAGIDACEAE, p. 79. |
| 53b. Leaves lobed, or irregularly pinnately cut or dissected; weedy plants with flowers in racemes | 2, in COMPOSITAE, p. 114. |
| 54a. Juice milky | 3, in EUPHORBIACEAE, p. 67. |
| 54b. Juice not milky or colored — 55. | |
| 55a. Leaves whorled — 56. | |
| 55b. Leaves all opposite — 58. | |
| 56a. Aquatic or mud plants with erect stems | 2a, in HALORAGIDACEAE, p. 79. |
| 56b. Prostrate weedy terrestrial plants | AIZOACEAE, p. 31. |
| 56c. Erect or ascending terrestrial plants — 57. | |
| 57a. Leaves more than 2.5 cm. long | 4a, in CORNACEAE, p. 83. |
| 57b. Leaves 2 cm. long or less | 3a, in PRIMULACEAE, p. 87. |
| 58a. Flowers in terminal or axillary spikes, racemes, or other clusters — 59. | |
| 58b. Flowers solitary or few in the axils of the leaves — 61. | |
| 59a. Leaves less than 5 mm. long | 1a, in GENTIANACEAE, p. 88. |
| 59b. Leaves more than 2 cm. long — 60. | |
| 60a. Inflorescence chiefly terminal, panicled | 2, in COMPOSITAE, p. 114. |
| 60b. Inflorescence chiefly axillary | URTICACEAE, p. 23. |
| 61a. Flowers on long pedicels | 2, in CARYOPHYLLACEAE, p. 31. |
| 61b. Flowers on short pedicels or sessile — 62. | |
| 62a. Stem erect, repeatedly branched; leaves linear to oblong | ILLECEBRACEAE, p. 31. |
| 62b. Stem decumbent or prostrate — 63. | |
| 63a. Leaves round, ovate, or kidney-shape, rounded at the base, crenate or lobed | 12a, in SAXIFRAGACEAE, p. 50. |
| 63b. Leaves of a narrower shape, entire, tapering toward the base — 64. | |
| 64a. Principal leaves 2-3 cm. long | 1a, in ONAGRACEAE, p. 78. |
| 64b. Principal leaves 1 cm. long or less — 65. | |
| 65a. Petals present | ELATINACEAE, p. 74. |
| 65b. Petals none | CALLITRICHACEAE, p. 68. |
| — 66— |
| 66a. Plants of the composite type, with several or many small flowerets closely aggregated into a dense head surrounded or subtended by a calyx-like involucre of small bracts — 67. | |
| 66b. Flowers solitary or variously clustered, but not in involucred heads — 70. | |
| 67a. Involucre of 4 conspicuous white bracts, much larger than the small flower-cluster | 4a, in CORNACEAE, p. 83. |
| 67b. Involucral bracts green or somewhat colored — 68. | |
| 68a. Stem more or less prickly | DIPSACACEAE, p. 112. |
| 68b. Stem and leaves not prickly — 69. | |
| 69a. Stem square; foliage aromatic when crushed | LABIATAE, p. 95. |
| 69b. Stem not square; foliage not with the odor of mint | COMPOSITAE, p. 113. |
| 70a. The conspicuous portion of the perianth1 composed of separate parts — 71. | |
| 70b. The conspicuous portion of the perianth1 composed of united parts — 97. | |
| 71a. Stem-leaves compound, or cleft to the very base — 72. | |
| 71b. Stem-leaves simple — 78. | |
| 72a. Stamens more than 10 in each flower — 73. | |
| 72b. Stamens 5-10 in each flower — 75. | |
| 73a. Ovary 1 in each flower | 2a, in PAPAVERACEAE, p. 41. |
| 73b. Ovaries several in each flower — 74. | |
| 74a. Leaves pinnately compound | 68a, in ROSACEAE, p. 57. |
| 74b. Leaves palmately compound | RANUNCULACEAE, p. 35. |
| 75a. Stamens 6 | 31, in CRUCIFERAE, p. 44. |
| 75b. Stamens 5 or 10 — 76. | |
| 76a. Leaflets reverse heart-shape; flowers yellow | OXALIDACEAE, p. 64. |
| 76b. Leaflets not reverse heart-shape; flowers white, greenish, or pink — 77. | |
| 77a. Flowers greenish or white, about 2 mm. broad | ARALIACEAE, p. 80. |
| 77b. Flowers 5 mm. broad or larger | GERANIACEAE, p. 64. |
| 78a. Juice milky — 79. | |
| 78b. Juice not milky — 80. | |
| 79a. A 3-lobed ovary with 3 short styles visible in some of the flowers | EUPHORBIACEAE, p. 66. |
| 79b. Ovaries 2 in the center of each flower (sometimes concealed by other organs); sepals and petals each 5 — 104. | |
| 80a. Perianth with one circle of parts only — 81. | |
| 80b. Each flower with both calyx and corolla — 82. | |
| 81a. Stem prostrate; flowers only 2 mm. broad | AIZOACEAE, p. 31. |
| 81b. Stem erect; flowers at least 20 mm. wide | 4a, in CORNACEAE, p. 83. |
| 82a. Petals 2 or 4 — 83. | |
| 82b. Petals 3 | 22, in LILIACEAE, p. 12. |
| 82c. Petals 5 or 6 — 84. | |
| 83a. Leaves with 3-5 principal veins | MELASTOMACEAE, p. 77. |
| 83b. Leaves with 1 principal mid-vein | ONAGRACEAE, p. 78. |
| 84a. Leaves palmately lobed — 85. | |
| 84b. Leaves entire or toothed, or with 1-2 small lobes near the base only — 86. | |
| 85a. Petals entire or notched at the end | GERANIACEAE, p. 64. |
| 85b. Petals conspicuously fringed | 23b, in SAXIFRAGACEAE, p. 51. |
| 86a. Ovary 1 — 87. | |
| 86b. Ovaries 2, surrounded and concealed by other organs | ASCLEPIADACEAE, p. 90. |
| 86c. Ovaries 4-5 | 2b, in CRASSULACEAE, p. 48. |
| 87a. Leaves dotted with translucent dots (easily seen when the leaf is held to the light) | HYPERICACEAE, p. 73. |
| 87b. Leaves not dotted with translucent dots — 88. | |
| 88a. Leaves only 1-3 mm. long, closely appressed and concealing the stem | 2a, in CISTACEAE, p. 74. |
| 88b. Leaves larger, not concealing the stem — 89. | |
| 89a. Style 1 or none — 90. | |
| 89b. Styles 2 to 7 — 94. | |
| 90a. Stamens 5 — 91. | |
| 90b. Stamens 10 — 92. | |
| 90c. Stamens neither 5 nor 10 — 93. | |
| 91a. Flowers blue, sessile in terminal spikes with leaf-like bracts | LYTHRACEAE, p. 77. |
| 91b. Flowers not in terminal bracted spikes | PRIMULACEAE, p. 87. |
| 92a. Leaves entire | LYTHRACEAE, p. 77. |
| 92b. Leaves toothed or crenate | ERICACEAE, p. 84. |
| 93a. Flowers irregular; petals 3 | POLYGALACEAE, p. 65. |
| 93b. Flowers regular; petals 5 or more | LYTHRACEAE, p. 77. |
| 94a. Sepals 2, partly attached to the ovary | PORTULACACEAE, p. 34. |
| 94b. Sepals 5, free from the ovary — 95. | |
| 95a. Stamens 5 — 96. | |
| 95b. Stamens not 5 | CARYOPHYLLACEAE, p. 31. |
| 96a. Flowers blue or yellow | LINACEAE, p. 63. |
| 96b. Flowers white or pinkish | CARYOPHYLLACEAE, p. 31. |
| — 97— |
| 97a. Perianth with but one circle of floral leaves — 98. | |
| 97b. Perianth consisting of both calyx and corolla — 101. | |
| 98a. Flowers small, in dense heads subtended by conspicuous bracts — 99. | |
| 98b. Flowers 2-5, in a colored spreading 5-lobed involucre | NYCTAGINACEAE, p. 31. |
| 98c. Flowers in various sorts of clusters or solitary, but never in heads with a conspicuous involucre — 100. | |
| 99a. Bracts 4, white and conspicuous; stem not thorny | 4a, in CORNACEAE, p. 83. |
| 99b. Bracts green; stem thorny | DIPSACACEAE, p. 112. |
| 100a. Stamens 3 | VALERIANACEAE, p. 111. |
| 100b. Stamens 4 or 5 | RUBIACEAE, p. 108. |
| 101a. Anthers more numerous than the lobes of the corolla — 102. | |
| 101b. Anthers just as many as the lobes of the corolla — 103. | |
| 101c. Anthers fewer than the lobes of the corolla — 110. | |
| 102a. Leaves simple | POLYGALACEAE, p. 65. |
| 102b. Leaves compound with 3 leaflets | OXALIDACEAE, p. 64. |
| 102c. Leaves finely dissected; stems climbing | 2a, in FUMARIACEAE, p. 41. |
| 103a. Ovaries 2 — 104. | |
| 103b. Ovary 1, but very deeply 4-lobed, with a single style | LABIATAE, p. 95. |
| 103c. Ovary 1, not deeply lobed — 105. | |
| 104a. Stamens united, surrounding and more or less concealing the ovaries, and not resembling ordinary stamens | ASCLEPIADACEAE, p. 90. |
| 104b. Stamens separate, of ordinary structure | APOCYNACEAE, p. 90. |
| 105a. Ovary inferior, appearing as a swelling below the calyx at the apex of the pedicel — 106. | |
| 105b. Ovary superior, located in the center of the flower — 107. | |
| 106a. Corolla 3-4-lobed | RUBIACEAE, p. 108. |
| 106b. Corolla 5-lobed | 3b, in CAPRIFOLIACEAE, p. 109. |
| 107a. Leaves toothed or deeply cut | VERBENACEAE, p. 99. |
| 107b. Leaves entire — 108. | |
| 108a. A stamen in front of the middle of each petal | PRIMULACEAE, p. 87. |
| 108b. Stamens located between the petals or lobes of the corolla, or else so far down in the tubular corolla that their position is not easily ascertained — 109. | |
| 109a. Corolla salver-form, with a very slender tube, and abruptly spreading lobes | POLEMONIACEAE, p. 92. |
| 109b. Corolla salver-form, with a wide tube and fringed blue petals | GENTIANACEAE, p. 88. |
| 109c. Corolla rotate, funnel-form, or bell-shape | GENTIANACEAE, p. 88. |
| 110a. Ovary deeply 4-lobed, appearing like 4 separate ovaries; style 1 | LABIATAE, p. 95. |
| 110b. Ovary not 4-lobed — 111. | |
| 111a. Stamens 2 — 112. | |
| 111b. Stamens 3 | VALERIANACEAE, p. 111. |
| 111c. Stamens 4 — 113. | |
| 112a. Flowers in dense heads | 1a, in ACANTHACEAE, p. 107. |
| 112b. Flowers solitary or in loose clusters | SCROPHULARIACEAE, p. 101. |
| 113a. Corolla distinctly 2-lipped and irregular — 114. | |
| 113b. Corolla not distinctly 2-lipped, its 5 lobes all alike or nearly so — 115. | |
| 114a. Calyx 2-lipped; the upper lip with 3 awl-shape teeth, the lower with 2 short teeth; flowers in slender terminal spikes | PHRYMACEAE, p. 107. |
| 114b. Calyx not obviously 2-lipped, its teeth equal or nearly so | SCROPHULARIACEAE, p. 101. |
| 115a. Flowers sessile or nearly so, in spikes — 116. | |
| 115b. Flowers in nodding pairs at the top of a slender stalk | 3a, in CAPRIFOLIACEAE, p. 109. |
| 115c. Flowers solitary or in clusters; not in spikes or nodding pairs — 117. | |
| 116a. Corolla not over 1 cm. long | VERBENACEAE, p. 99. |
| 116b. Corolla 1.5 cm. long or more | SCROPHULARIACEAE, p. 101. |
| 117a. Calyx-lobes 15-25 mm. long; flowers blue, 3-5 cm. long; calyx without an obvious tube | 2, in ACANTHACEAE, p. 107. |
| 117b. Calyx-lobes united below into an obvious calyx-tube | SCROPHULARIACEAE, p. 101. |
| — 118— |
| 118a. Leaves deeply lobed, compound, or dissected — 119. | |
| 118b. Leaves simple and not deeply lobed — 129. | |
| 119a. Leaves once-pinnately compound or lobed — 120. | |
| 119b. Leaves once-palmately compound or lobed — 124. | |
| 119c. Leaves dissected or 2-3 times compound — 125. | |
| 120a. Leaves merely lobed — 121. | |
| 120b. Leaves actually compound — 123. | |
| 121a. Flowers axillary; marsh or swamp plants | HALORAGIDACEAE, p. 79. |
| 121b. Flowers in terminal clusters — 122. | |
| 122a. Stamens 2-6; taste mustard-like | 52b, in CRUCIFERAE, p. 46. |
| 122b. Stamens 10 or more | RESEDACEAE, p. 48. |
| 123a. Leaflets entire | LIMNANTHACEAE, p. 68. |
| 123b. Leaflets serrate | 70a, in ROSACEAE, p. 57. |
| 124a. Flowers solitary | 31a, in RANUNCULACEAE, p. 38. |
| 124b. Flowers in dense terminal umbels or heads | UMBELLIFERAE, p. 80. |
| 124c. Flowers in terminal racemes | 2a, in COMPOSITAE, p. 114. |
| 124d. Flowers in axillary spikes or panicles | 9b, in URTICACEAE, p. 24. |
| 125a. Leaves merely dissected, not truly compound with distinct leaflets — 126. | |
| 125b. Leaves truly compound, with distinct petiolate leaflets — 127. | |
| 126a. Flowers in axillary clusters | CHENOPODIACEAE, p. 28. |
| 126b. Flowers in terminal clusters | COMPOSITAE, p. 113. |
| 127a. Stamens 5; flowers in umbels — 128. | |
| 127b. Stamens 6; flowers in small clusters | 3b, in BERBERIDACEAE, p. 40. |
| 127c. Stamens many; flowers in racemes or panicles | RANUNCULACEAE, p. 35. |
| 128a. Styles 5 | ARALIACEAE, p. 80. |
| 128b. Styles 2 | UMBELLIFERAE, p. 80. |
| 129a. Flowers in dense cottony heads; plants more or less white-woolly | 79, in COMPOSITAE, p. 120. |
| 129b. Pistillate flowers in an ovoid spiny involucre, ripening into a bur | 3a, in COMPOSITAE, p. 114. |
| 129c. Flowers minute, subtended by palmately cleft axillary bracts | 1a, in EUPHORBIACEAE, p. 66. |
| 129d. Plants without any of the preceding characters — 130. | |
| 130a. Plants with milky or colored juice | 10, in EUPHORBIACEAE, p. 67. |
| 130b. Plants with tendrils, at least on the upper leaves | 4a, in LILIACEAE, p. 11. |
| 130c. Plants of nettle-like character, with stinging hairs | 8b, in URTICACEAE, p. 24. |
| 130d. Plants with sheathing stipules, surrounding the stem above the base of each leaf | POLYGONACEAE, p. 25. |
| 130e. Plants with smooth, pale, juicy, almost translucent stems | 12a, in URTICACEAE, p. 24. |
| 130f. Plants without any of the preceding structures or habits — 131. | |
| 131a. Flowers axillary, solitary or in few-flowered clusters — 132. | |
| 131b. Flowers in terminal, or terminal and axillary clusters — 138. | |
| 132a. Leaves linear | CHENOPODIACEAE, p. 28. |
| 132b. Leaves of a broader shape than linear — 133. | |
| 133a. Flower-clusters with bracts as long as or longer than the flowers — 134. | |
| 133b. Flowers without conspicuous bracts — 135. | |
| 134a. Leaves broadest below the middle | 8a, in URTICACEAE, p. 24. |
| 134b. Leaves broadest above the middle | 2, in AMARANTHACEAE, p. 30. |
| 135a. Principal leaves 3 cm. long or more — 136. | |
| 135b. Principal leaves 2.5 cm. long or less — 137. | |
| 136a. Flowers nodding in the axils of the leaves | 1a, in VIOLACEAE, p. 75. |
| 136b. Flowers erect in the axils | 2a, in ONAGRACEAE, p. 78. |
| 137a. Leaves narrowly oblong | 1a, in HALORAGIDACEAE, p. 79. |
| 137b. Leaves roundish and somewhat heart-shape | 12a, in SAXIFRAGACEAE, p. 50. |
| 138a. Flowers in racemes or simple spikes — 139. | |
| 138b. Flowers in panicles or other branched clusters — 141. | |
| 139a. Leaves toothed or lobed | 52b, in CRUCIFERAE, p. 46. |
| 139b. Leaves entire — 140. | |
| 140a. Flowers sessile; leaves heart-shape | PIPERACEAE, p. 19. |
| 140b. Flowers pedicelled; leaves obovate | 8b, in PRIMULACEAE, p. 87. |
| 141a. Individual flowers distinct from each other, on pedicels — 142. | |
| 141b. Individual flowers crowded in close clusters, or separate and sessile — 143. | |
| 142a. Leaves finely serrate | 3b, in CRASSULACEAE, p. 49. |
| 142b. Leaves entire | 1b, in CISTACEAE, p. 74. |
| 143a. Flower-clusters mingled with sharp-pointed bracts | AMARANTHACEAE, p. 30. |
| 143b. Flower-clusters without bracts, or (rarely) with bracts which are not sharp-pointed | CHENOPODIACEAE, p. 28. |
| — 144— |
| 144a. Juice not milky — 145. | |
| 144b. Juice milky; apparent flowers consisting of a few white or colored petal-like bracts, inclosing a few inconspicuous flowers without petals. In some of them a 3-lobed ovary with 3 styles may be plainly seen | |
| 145a. Plants of the composite type, with several or many small flowerets closely aggregated into a dense head subtended by a calyx-like involucre of small bracts — 146. | EUPHORBIACEAE, p. 66. |
| 145b. Flowers solitary or in clusters, but not in involucred heads — 147. | |
| 146a. Leaves compound with 3 leaflets; stipules present | LEGUMINOSAE, p. 58. |
| 146b. Stipules none | COMPOSITAE, p. 113. |
| 147a. Leaves compound or deeply lobed — 148. | |
| 147b. Leaves simple and not deeply lobed — 154. | |
| 148a. Flowers irregular | LEGUMINOSAE, p. 58. |
| 148b. Flowers regular — 149. | |
| 149a. Petals 3 | LIMNANTHACEAE, p. 68. |
| 149b. Petals 4 — 150. | |
| 149c. Petals 5 or more — 151. | |
| 150a. Stamens 4 | 70a, in ROSACEAE, p. 57. |
| 150b. Stamens 6 | CRUCIFERAE, p. 42. |
| 150c. Stamens numerous | 43, in RANUNCULACEAE, p. 39. |
| 151a. Flowers in heads or umbels — 152. | |
| 151b. Flowers in slender spikes or racemes — 153. | |
| 152a. Styles 2 | UMBELLIFERAE, p. 80. |
| 152b. Styles 5 | ARALIACEAE, p. 80. |
| 153a. Leaves ternately compound | 43, in RANUNCULACEAE, p. 39. |
| 153b. Leaves once-pinnately compound | 50b, in ROSACEAE, p. 55. |
| 154a. Flowers irregular — 155. | |
| 154b. Flowers regular — 156. | |
| 155a. Stamens 2 | 40b, in SCROPHULARIACEAE, p. 104. |
| 155b. Stamens 5 or 10 | SAXIFRAGACEAE, p. 49. |
| 155c. Stamens 6 or 8 | POLYGALACEAE, p. 65. |
| 156a. With sheathing stipules surrounding the stem at the base of each leaf | POLYGONACEAE, p. 24. |
| 156b. Stipules not encircling the stem, or none — 157. | |
| 157a. Petals 3 | CISTACEAE, p. 74. |
| 157b. Petals 4 — 158. | |
| 157c. Petals 5 — 161. | |
| 158a. Stamens 2 — 159. | |
| 158b. Stamens 6 | CRUCIFERAE, p. 42. |
| 158c. Stamens 8 — 160. | |
| 159a. Corolla perfectly regular; flowers in terminal clusters without bracts, becoming racemes; taste peppery | 52a, in CRUCIFERAE, p. 46. |
| 159b. Corolla slightly irregular; flowers in bracted clusters, or axillary; taste not peppery | 40b, in SCROPHULARIACEAE, p. 104. |
| 160a. Delicate trailing evergreen, with flowers solitary in the axils and nearly or quite hidden beneath the leaves | 22b, in ERICACEAE, p. 85. |
| 160b. Erect or nearly so; flowers in terminal clusters | 12b, in ONAGRACEAE, p. 78. |
| 161a. Leaves sword-shape, finely parallel-veined, with bristly margins | 2a, in UMBELLIFERAE, p. 80. |
| 161b. Leaves not sword-shape — 162. | |
| 162a. Leaves toothed or lobed — 163. | |
| 162b. Leaves entire — 164. | |
| 163a. Stems creeping | 2b, in UMBELLIFERAE, p. 80. |
| 163b. Stems erect or nearly so | SAXIFRAGACEAE, p. 49. |
| 164a. Flowers in open panicles; leaves principally basal | SAXIFRAGACEAE, p. 49. |
| 164b. Flowers in rounded or flattened clusters; leaves principally on the stem | SANTALACEAE, p. 24. |
| 164c. Flowers in racemes, which become elongated at maturity — 165. | |
| 165a. Foliage glabrous | 8b, in PRIMULACEAE, p. 87. |
| 165b. Foliage pubescent | BORAGINACEAE, p. 93. |
| — 166— |
| 166a. Juice milky or colored — 167. | |
| 166b. Juice watery, not colored — 172. | |
| 167a. Apparent flowers consisting of a few petal-like bracts, inclosing a few inconspicuous flowers without petals. In some of them a 3-lobed ovary with 3 styles may be seen | EUPHORBIACEAE, p. 66. |
| 167b. Plants of the composite type, with several or many small flowerets closely aggregated in dense heads subtended by a calyx-like involucre of small bracts | 11, in COMPOSITAE, p. 115. |
| 167c. Flowers never aggregated in involucred clusters resembling a single flower — 168. | |
| 168a. Corolla very irregular; stamens protruding | LOBELIACEAE, p. 113 |
| 168b. Corolla regular — 169. | |
| 169a. Stamens with ordinary visible anthers; ovary 1 — 170. | |
| 169b. Stamens so grown together and to the stigma as to be almost unrecognizable; ovaries 2 | ASCLEPIADACEAE, p. 90. |
| 170a. Petals separate | PAPAVERACEAE, p. 41. |
| 170b. Petals united — 171. | |
| 171a. Stamens attached to the tube of the corolla | CONVOLVULACEAE, p. 91. |
| 171b. Stamens attached at the very base of the corolla | CAMPANULACEAE, p. 112. |
| 172a. Plants of the composite type, with several or many small flowerets closely aggregated into dense heads subtended by a calyx-like involucre of small bracts — 173. | |
| 172b. Flowers solitary or clustered, but not in involucred heads — 174. | |
| 173a. True composites, without a normal calyx | COMPOSITAE, p. 113. |
| 173b. A normal calyx with each floweret; leaves compound with 3 leaflets | LEGUMINOSAE, p. 58. |
| 174a. Flowers irregular, i. e., the conspicuous lobes of the perianth unlike in size or shape — 175. | |
| 174b. Flowers regular — 185. | |
| 175a. Stamens 2 or 4 | SCROPHULARIACEAE, p. 101. |
| 175b. Stamens 5 — 176. | |
| 175c. Stamens 6 — 181. | |
| 175d. Stamens 8; leaves simple | POLYGALACEAE, p. 65. |
| 175e. Stamens 10; leaves usually compound | LEGUMINOSAE, p. 58. |
| 175f. Stamens more than 10 — 183. | |
| 176a. Petals separate — 177. | |
| 176b. Petals united — 179. | |
| 177a. Flowers greenish or purplish, in a panicle | SAXIFRAGACEAE, p. 49. |
| 177b. Flowers white or purplish, in compound umbels | UMBELLIFERAE, p. 80. |
| 177c. Flowers solitary, or in few-flowered clusters — 178. | |
| 178a. Flowers blue, yellow, or white, in spring | VIOLACEAE, p. 75. |
| 178b. Flowers red-orange or yellow, in summer | BALSAMINACEAE, p. 71. |
| 178c. Flowers small and greenish, in spring | 1a, in VIOLACEAE, p. 75. |
| 179a. Anthers united; stamens protruding from the very irregular corolla | LOBELIACEAE, p. 113. |
| 179b. Anthers separate; corolla almost regular — 180. | |
| 180a. Corolla rotate; some or all filaments hairy | 2, in SCROPHULARIACEAE, p. 101. |
| 180b. Corolla funnel-form, dull yellow and purple; filaments not hairy | 12a, in SOLANACEAE, p. 101. |
| 180c. Corolla funnel-form, blue or violet; filaments not hairy | 7b, in BORAGINACEAE, p. 94. |
| 181a. Leaves compound or dissected | FUMARIACEAE, p. 41. |
| 181b. Leaves simple — 182. | |
| 182a. Flowers solitary | ARISTOLOCHIACEAE, p. 25. |
| 182b. Flowers in spikes, heads, or racemes | POLYGALACEAE, p. 65. |
| 183a. Leaves truly compound — 184. | |
| 183b. Leaves palmately cleft; flowers 15 mm. wide or larger | 6a, in RANUNCULACEAE, p. 36. |
| 183c. Leaves irregularly cleft; flowers about 5 mm. wide | RESEDACEAE, p. 48. |
| 184a. Petals prolonged backward into hollow spurs | 6b, in RANUNCULACEAE, p. 36. |
| 184b. Petals not prolonged into spurs | CAPPARIDACEAE, p. 47. |
| — 185— |
| 185a. Perianth consisting of one circle of parts only (usually considered to be the calyx) — 186. | |
| 185b. Perianth consisting of both calyx and corolla — 192. | |
| 186a. Leaves with sheathing stipules encircling the stem above the base of every leaf | POLYGONACEAE, p. 25. |
| 186b. Leaves without sheathing stipules — 187. | |
| 187a. Leaves entire — 188. | |
| 187b. Leaves toothed, lobed, or compound — 190. | |
| 188a. Stamens 5 | SANTALACEAE, p. 24. |
| 188b. Stamens 6 — 189. | |
| 188c. Stamens 10 | PHYTOLACCACEAE, p. 30. |
| 189a. Perianth-lobes 3; perianth-tube curved | ARISTOLOCHIACEAE, p. 25. |
| 189b. Perianth-lobes 6, spreading | 4a, in LILIACEAE, p. 11. |
| 190a. Stamens 5 | UMBELLIFERAE, p. 80. |
| 190b. Stamens 6 — 191. | |
| 190c. Stamens more than 6 | RANUNCULACEAE, p. 35. |
| 191a. Climbing plant with heart-shape perianth | 2a, in FUMARIACEAE, p. 41. |
| 191b. Erect plant, with spreading perianth | 3b, in BERBERIDACEAE, p. 40. |
| 192a. Corolla composed of united petals — 193. | |
| 192b. Corolla composed of separate petals — 208. | |
| 193a. Stamens 2 or 4 | SCROPHULARIACEAE, p. 101. |
| 193b. Stamens 3; climbing vines | CUCURBITACEAE, p. 112. |
| 193c. Stamens 5 — 194. | |
| 193d. Stamens 6 | 2a, in FUMARIACEAE, p. 41. |
| 193e. Stamens 8 | 22b, in ERICACEAE, p. 85. |
| 193f. Stamens 10 — 207. | |
| 193g. Stamens very numerous | MALVACEAE, p. 72. |
| 194a. Ovaries 2; flowers orange-red, in umbels | 7a, in ASCLEPIADACEAE, p. 91. |
| 194b. Ovary 1, deeply 4-lobed; flowers in racemes | BORAGINACEAE, p. 93. |
| 194c. Ovary 1, not deeply lobed — 195. | |
| 195a. Climbing or scrambling vines — 196. | |
| 195b. Not climbing or scrambling — 198. | |
| 196a. Flowers about 1 cm. wide — 197. | |
| 196b. Flowers 2-8 cm. wide | CONVOLVULACEAE, p. 91. |
| 197a. Leaves 1 cm. wide or less | 2b, in CAMPANULACEAE, p. 112. |
| 197b. Leaves 2 cm. wide or more | 4a, in SOLANACEAE, p. 100. |
| 198a. Flowers solitary, either terminal or axillary — 199. | |
| 198b. Flowers in terminal clusters — 201. | |
| 199a. Calyx concealed by 2 bracts | CONVOLVULACEAE, p. 91. |
| 199b. Calyx not completely concealed by bracts — 200. | |
| 200a. Ovary inferior, appearing as a swelling below the calyx at the base of the flower, 3-celled; stigma 3-lobed | CAMPANULACEAE, p. 112. |
| 200b. Ovary superior, located in the center of the flower | SOLANACEAE, p. 100. |
| 201a. Some or all filaments hairy — 202. | |
| 201b. Filaments not hairy — 203. | |
| 202a. Leaves lobed or divided | HYDROPHYLLACEAE, p. 93. |
| 202b. Leaves not lobed | 2, in SCROPHULARIACEAE, p. 101. |
| 203a. Anthers close together, longer than the filaments | 2, in SOLANACEAE, p. 100. |
| 203b. Anthers separate from each other — 204. | |
| 204a. Leaves compound or very deeply lobed — 205. | |
| 204b. Leaves simple or with shallow lobes only — 206. | |
| 205a. Leaf-segments linear or oblong, irregular | HYDROPHYLLACEAE, p. 93. |
| 205b. Leaves truly compound with separate leaflets | 1a, in POLEMONIACEAE, p. 92. |
| 206a. Flowers greenish-yellow | SOLANACEAE, p. 100. |
| 206b. Flowers blue, violet, white, or intermediate tints | CAMPANULACEAE, p. 112. |
| 207a. Leaves simple | ERICACEAE, p. 84. |
| 207b. Leaves compound | OXALIDACEAE, p. 64. |
| — 208— |
| 208a. Petals 4 — 209. | |
| 208b. Petals 5 — 212. | |
| 208c. Petals 6 or more — 227. | |
| 209a. Stamens 4 or 8 — 210. | |
| 209b. Stamens 6, 4 long and 2 short | CRUCIFERAE, p. 42. |
| 209c. Stamens 9 or more | CAPPARIDACEAE, p. 47. |
| 210a. Leaves compound | ROSACEAE, p. 51. |
| 210b. Leaves simple — 211. | |
| 211a. Ovary 1, inferior, appearing as a swelling below the calyx | ONAGRACEAE, p. 78. |
| 211b. Ovaries 4 or 5, in the center of the flower | CRASSULACEAE, p. 48. |
| 212a. Stamens with good anthers 5 — 213. | |
| 212b. Stamens 6 to 10 — 217. | |
| 212c. Stamens more than 10 — 222. | |
| 213a. Flowers solitary, terminating the stem | 12b, in SAXIFRAGACEAE, p. 50. |
| 213b. Flowers axillary, solitary or in small clusters — 214. | |
| 213c. Flowers several, in loose irregular terminal clusters; leaves simple | LINACEAE, p. 63. |
| 213d. Flowers in slender spike-like racemes; leaves compound | 50b, in ROSACEAE, p. 55. |
| 213e. Flowers in panicles | 20a, in SAXIFRAGACEAE, p. 50. |
| 213f. Flowers in umbels — 216. | |
| 214a. Leaves compound | 25b, in LEGUMINOSAE, p. 60. |
| 214b. Leaves simple — 215. | |
| 215a. Flowers blue or yellow, erect or spreading | LINACEAE, p. 63. |
| 215b. Flowers greenish, nodding | 1a, in VIOLACEAE, p. 75. |
| 216a. Flowers pink or purple | GERANIACEAE, p. 64. |
| 216b. Flowers yellow or white | UMBELLIFERAE, p. 80. |
| 217a. Leaves compound with 3 leaflets — 218. | |
| 217b. Leaves pinnately compound — 219. | |
| 217c. Leaves deeply palmately lobed | GERANIACEAE, p. 64. |
| 217d. Leaves simple and not deeply lobed — 220. | |
| 218a. Leaflets reverse heart-shape; flowers yellow | OXALIDACEAE, p. 64. |
| 218b. Leaflets taper-pointed; flowers white or pink | 73, in ROSACEAE, p. 57. |
| 219a. Leaflets entire | 24, in LEGUMINOSAE, p. 60. |
| 219b. Leaflets toothed | 50b, in ROSACEAE, p. 55. |
| 220a. Prostrate plants, with thick, fleshy, entire leaves | 3, in PORTULACACEAE, p. 34. |
| 220b. Bushy branched plants, with small gray leaves concealing the stem | 2a, in CISTACEAE, p. 74. |
| 220c. Erect or spreading plants — 221. | |
| 221a. Ovary 1, style 1 | 4a, in ERICACEAE, p. 84. |
| 221b. Ovary with 2 distinct styles | SAXIFRAGACEAE, p. 49. |
| 221c. Ovaries 5; styles 5 | CRASSULACEAE, p. 48. |
| 222a. Stamens united by their filaments into a tube | MALVACEAE, p. 72. |
| 222b. Stamens separate from each other — 223. | |
| 223a. Leaves with stipules; ovaries more than 1 | ROSACEAE, p. 51. |
| 223b. Leaves without stipules — 224. | |
| 224a. Leaves toothed, deeply lobed, or compound | RANUNCULACEAE, p. 35. |
| 224b. Leaves entire — 225. | |
| 225a. Ovaries numerous | RANUNCULACEAE, p. 35. |
| 225b. Ovary 1 — 226. | |
| 226a. Sepals 2 | PORTULACACEAE, p. 34. |
| 226b. Sepals 3 or 5 | CISTACEAE, p. 74. |
| — 227— |
| 227a. Leaves entire | LYTHRACEAE, p. 77. |
| 227b. Leaves lobed, divided, dissected, or compound — 228. | |
| 228a. Flowers in slender racemes | RESEDACEAE, p. 48. |
| 228b. Flowers solitary or clustered, but not in slender racemes — 229. | |
| 229a. Stamens 6 | 3b, in BERBERIDACEAE, p. 40. |
| 229b. Stamens numerous | RANUNCULACEAE, p. 35. |