100(99). Usually a long hypanthium present and prolonged above and com- 

 pletely obscuring the top of the ovary; stamens (often 8) usually 



precisely twice as numerous as the petals; fruit a capsule 



95. Onagraceae, p. 1175 



100. Top of ovary plainly visible at or slightly above the point of attachment 



of the stamens and perianth; fruit a capsule, berry or follicetum 

 (101) 



101(100). Plants partially submerged weak-stemmed aquatics (genus Myrio- 

 phyllum of) 96. Haloragaceae, p. 1201 



101. Plants not partially submerged 70. Saxifragaceae p. 999 



102(95). Filaments monadelphous or diadelphous, or confluent with a gynophore 

 (anthers free or united) (103) 



102. Filaments distinct from each other or joined into more than 2 groups (108) 



103(102). Pistil solitary and simple, often folliclelike at maturity; stigma solitary 

 74. Legiiminosae, p. 1039 



103. Pistil solitary but compound, rarely folliclelike; stigmas mostly more than 1 



(104) 



104(103). Flowers strongly bilaterally symmetrical; carpels usually 2; stamens 

 monadelphous or diadelphous 77. Polygalaceae, p. 1074 



104. Flowers nearly radially symmetrical; carpels more than 2; stamens monadel- 



phous (105) 



105(104). Filament tube elongate and forming a more or less loose sheath not 

 only around the ovary but also around the elongate style(s); 

 stamens numerous; flowers perfect 87. Malvaceae, p. 1113 



105. Filament tube not so elongate (or if so then stamens only 10); stamens 



numerous or fewer; flowers perfect or unisexual (106) 



106(105). Carpels 3 as shown by number of stigmas or placentas 



78. Euphorbiaceae, p. 1082 



106. Carpels 5 (107) 



107(106). Fruit separating at maturity into 5 or 10 uni- or biovulate mericarps 

 which fall separately 76. Linaceae, p. 1073 



107. Fruit not a schizocarp or if so then the cells several-seeded 



88. Sterculiaceae, p. 1 125 



108(102). Aquatic perennial herbs with thick horizontal rhizomes, rooted in mud 

 at bottom of water; leaves (at least those borne at or near the sur- 

 face of the water) usually peltate or very deeply rounded- 

 cordate 59. Nymphaeaceae, p. 900 



108. Habit not as in the water-lily family (109) 



109(108). Pistils several (each simple) and quite separate (even at base) at 

 all stages of development (110) 



109. Pistil 1. either simple or compound (in some taxa the carpels united only 



near their bases as for example the Magnoliaceae, Saxifragaceae 

 and Hamamelidaceae) (112) 



110(109). Flowers with a floral cup (or "hypanthium") at the rim of which 

 are attached the sepals, petals and stamens; stipules usually present; 

 endosperm absent 73. Rosaceae, p. 1015 



110. Calyx, corolla and androecium hypogynous or nearly so; stipules present or 



often absent; endosperm usually present (111) 



32 



