12 General Key to Families 



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7B. Leaves simple Fam. 66. Fagaceae, 376 



2B. Flowers not in aments. 



8A. Carpels 2 to numerous, free or slightly adherent. 

 9A. Calyx absent. 



lOA. Trees or shrubs; flowers in racemes or fascicles. 



11 A. Leaves palmately veined; flowers unisexual, fasciculate; fruit a follicle Fam. 89. Cercidiphyllaceae, 439 



IIB. Leaves pinnately veined; flowers perfect. 



12 A. Trees with evergreen leaves; flowers in racemes, carpels sessile, shortly connate and slightly embedded in the 



receptacle; fruit dehiscent Fam. 87. Trochodendraceae, 438 



123. Trees with deciduous leaves; flowers axillary in fascicles; carpels wholly free, pedicelled, indehiscent. 



Fam. 88. Eupteleaceae, 438 



lOB. Herbs with a racemose inflorescense Fam. 59. Saururaceae, 359 



9B. Calyx present. 



13A. Leaves opposite; herbs or climbing plants with somewhat woody stems. 



14A. Fruit a cluster of follicles or achenes, rarely solitary Fam. 90. Ranunculaceae, 439 



14B. Fruit an aggregation of fleshy carpels forming a berrylike structure Fam. 81. Phytolaccaceae, 420 



13B. Leaves alternate; trees, shrubs or climbing woody vines. 



15A. Leaves simple Fam. 94. Magnoliaceae, 467 



15B. Leaves compound. 



16A. Trees and shrubs with pellucid oil-glands; leaves pinnately or ternately compound Fam. 110. Rutaceae, 581 



1 6B. Woody climbing plants without pellucid oil-glands; leaves palmately or ternately compound. 



Fam. 91. Lardizabalaceae, 461 

 8B. Carpel 1 or usually more and united into a compound ovary. 

 17 A. Calyx absent; ovary superior. 



18A. Plants flat and thalloid, growing on rocks in running water Fam. 70. Podostemaceae, 393 



18B. Plants terrestrial or aquatic, with stems and leaves. 



19A. Aquatic plants with finely dissected verticillate leaves Fam. 86. Ceratophyllaceae, 438 



19B. Terrestrial plants, or, if aquatic, the leaves always simple and not verticillate. 



20A. Plants dioecious, arborescent, evergreen Fam. 114. Euphorbiaceae, 588 



20B. Plants monoecious, deciduous, arborescent, or, if evergreen, the flowers perfect. 



21A. Flowers naked, included in a cup-shaped involucre (cyathium), the staminate flowers marginal, the pistillate 



central; plants with milky juice Fam. 114. Euphorbiaceae, 588 



21B. Flowers with a perianth, in spikes or racemes; plants without milky juice. 



22 A. Root-parasites; leaves scalelike without chlorophyll; inflorescence ovoid to subcylindric, thick, very many 



flowered Fam. 77. Balanophoraceae, 402 



22B. Nonparasitic; leaves with chlorophyll. 



23A. Flowers unisexual; plants diminutive with simple opposite leaves, aquatic or in wet places. 



Fam. 115. Callitrichaceae, 594 

 23B. Flowers perfect; plants usually of more robust stature. 



24A. Leaves trifoliolate or 3-pinnate; anthers opening by valves Fam. 92. Berberidaceae, 461 



24B. Leaves simple; anthers longitudinally dehiscent. 

 25A. Ovules solitary. 



26A. Leaves entire, usually alternate Fam. 60. Piperaceae, 359 



26B. Leaves serrate, opposite Fam. 61. Chloranthaceae, 360 



25B. Ovules several, on parietal placentae Fam. 59. Saururaceae, 359 



17b. Calyx present; ovary superior to inferior. 



27A. Flowers minute and numerous, entirely enclosed within a thick ovoid or pyriform to globose receptacle (syconium); 



plants with milky juice Fam. 68. Moraceae (Ficus), 384 



27B. Flowers not enclosed within a receptacle. 



28A. Ovary inferior or perianth perigynous and the ovary superior. 



29A. Plants parasitic epiphytes Fam. 74. Loranthaceae, 396 



29B. Plants terrestrial. 



30A. Whole plant covered with stellate hairs or scales Fam. 143. Elaeagnaceae, 646 



3 OB. Plants glabrous or pubescent, not stellate. 



31A. Calyx actinomorphic, 2- or 3-lobed, or distinctly zygomorphic. 



32A. Flowers perfect; stamens 3, 6, or 12; fruit berrylike or capsular, many-seeded. Fam. 75. Aristolochiaceae, 397 



32B. Flowers unisexual; stamens more than 12; fruit an achene Fam. 152. Theligonaceae, 661 



31B. Calyx actinomorphic, 4- or 5-lobed. 

 33 A. Styles more than 2. 



34A. Leaves verticillate Fam. 150. Haloragaceae, 659 



34B. Leaves alternate. 



35A. Leaves simple Fam. 82. Aizoaceae, 421 



35B. Leaves pinnate Fam. 104. Rosaceae, 517 



33B. Style 1. 



36A. Seeds many Fam. 149. Onagraceae, 654 



36B. Seeds 1 or few. 



37A. Leaves verticillate; aquatic Fam. 151. Hippuridaceae, 661 



37B. Leaves alternate or opposite; terrestrial. 



38A. Ovules several in each locule of the ovary Fam. 73. Santalaceae, 395 



