KEY TO THE ORDERS. xix 



Stamens inserted below the ovary. 



Families in Order 25. RANALES. 134 

 Stamens inserted on the edge of a cup-shaped hypanthium. 



Families in Order 27. ROSALES. 169 

 Gynoecium of 2 or several united carpels; stigmas or styles 2 or 



several. 



Ovary, by abortion, i -celled and i-ovuled. 

 Leaves with sheathing stipules (ocreae). 



Order 23. POLYGONALES. 101 

 Leaves estipulate, or if stipules are present they are not 



sheathing. 

 Trees or shrubs ; ovary not seated in a hypanthium. 



Ulmaceae in Order 21. URTICALES. 100 

 Herbs or vines. 



Stipules herbaceous : inflorescence spicate or racemose : 

 leaf-blades palmately veined. 



Cannabinacese in Order 21. URTICALES. 100 

 Stipules scarious or hyaline or none ; inflorescence cy- 

 mose : leaf-blades pinnately veined. 



Families in Order 24. CHENOPODIALES. 113 

 Ovary several-celled, or with several placentae, several-ovuled. 

 Stamens hypogynous, inserted under the gynoecium in the per- 

 fect flowers, not on a disk in the pistillate flowers. 

 Flowers perfect. 



Stamens not tetradynamous. 



Stamens 2 ; inflorescence spicate. 



Besseya in Order 44. POLEMONIALES. 313 

 Stamens 3-10; inflorescence cymose. 



Order 24. CHENOPODIALES. 113 

 Stamens tetradynamous. 



Brassicaceae in Order 26. PAPAVERALES. 150 

 Flowers monoecious or dioecious. 



Euphorbiaceae in Order 30. EUPHORBIALES. 222 

 Stamens perigynous or epigynous, inserted on the margin of a 



hypanthium or a disk. 



Fruit a samara. Aceraceae in Order 31. SAPINDALES. 226 



Fruit drupe-like or berry-like. Order 32. RHAMNALES. 227 



b. Ovary inferior. 



Flowers not in involucrate heads. 



Fruit a berry or a drupe, or nut-like. 



Stamens as many as the perianth-members and alternate with 

 them, or fewer. 



Tetragoniaceae in Order 24. CHENOPODIALES. 124 

 Stamens as many as the perianth-members and opposite them, 



or twice as many. Families in Order 37. MYRTALES. 240 



Fruit a capsule. 



Sepals as many as the ovary-cavities or one-half as many. 



Order 37. MYRTALES. 240 



Sepals (4-5) at least twice as many as the ovary-cavities. 

 Styles 2-3 ; leaves alternate. 



Saxifragaceae in Order 27. ROSALES. 170 

 Styles solitary ; leaves opposite. 



Glaux in Order 40. PRIMULALES. 264 

 Flowers, at least the staminate, in involucrate heads. 



Ambrosiaceae in Order 49. CARDUALES. 327 

 B. Corolla present. 



I. Petals distinct, at least at the base. 



i. Carpels solitary, or several and distinct, or united only at the base. 

 Stamens at the base of the receptacle, i. e., hypogynous. 



