KEY TO THE ORDERS 
Stamens borne on the margin of a disc or hypanthium. 
ROSALES: 122. 
Carpels several and united. 
Stamens borne at the base of the receptacle. 
Stamens numerous, more than twice as many as the petals. 
Stamen filaments distinct. 
Aquatics with floating leaves. Nymphaeaceae: 56. 
Terrestrial plants or if aquatic leaves not floating. 
RHOEODALES: 57. 
Stamen filaments united. 
’ Filaments united into a tube around the styles. 
MALVALES: 89. 
Filaments in several sets, not forming a tube. 
Trees. MALVALES: 89. 
Herbs or shrubs. GUTTIFERALES: 86. 
Stamens few, not more than twice as many as the petals. 
Stamens as many as the petals and opposite them. 
Flowers monoecious, Euphorbiaceae: 83. 
Flowers perfect. Portulaceae: 69. 
Stamens as many as the petals and alternate with them, 
or more; often twice as many. 
Stamens 6, rarely 2, petals 4. RHOEODALES: 57. 
Stamens as many as the petals or twice as many. 
Ovary one celled. 
Placentae central or basal.CARYOPHYLLALES: 64. 
Placentae parietal. GUTTIFERALES: 86. 
Ovary several celled. 
Stamens not adnate to the gynoecium, 
Filaments partly or wholly united. 
: GERANIALES: 80. 
Filaments distinct. 
Ovules numerous in each cavity of the ovary. 
ERICALES: 94. 
Ovules few or solitary in each cavity of the 
ovary. 
Flowers regular. GERANIALES: 80, 
Flowers irregular, Aesculus: 154, 
Stamens adnate to the gynoecium. Asclepiadaceae: 107. 
Stamens borne on the margin of a disk or hypanthium. 
Stamens as many as the petals and opposite them. 
Styles distinct, ovules numerous. Heuchera: 142. 
Styles united, ovules 1 or 2 in each cavity of the ovary. 
CELASTRALES: 151. 
Stamens as many as the petals and alternate with them or 
more, 
Hypanthium flat or obsolete, not enclosing the ovary. 
Ovary one celled, fruit a small drupe. 
Anacardiaceae: 154. 
Ovary 2-several celled, fruit a dehiscent pod or capsule. 
CELASTRALES: 151. 
Hypanthium enclosing the ovary but free from it. 
Lythraceae: 143, 
