10 ANALYTICAL KEY 



FLOWERS NOT IN AMENTS 



Ovary or its cells 1-2 (rarely 8~4)-ovuled. 



Pistils more than 1, distinct or nearly so. 



Stamens inserted on the calyx; leaves with stipules 54. ROSACEAE, 245 



Stamens inserted on the receptacle; calyx present, usually petal- 

 like 45. RANUNCULACEAE, 189 

 Pistil 1, simple or compound. 



Ovary free from the calyx, which is sometimes wanting. 



Stipules (ochreae) sheathing the stem at the nodes 36. POLYGONACEAE, 147 

 Stipules (if present) not sheathing the stem. 

 Herbs. 



Aquatics, submerged or nearly so. 



Leaves whorled, dissected; style 1 44. CERATOPHYLLACEAE, 189 



Leaves opposite, entire; styles 2 65. CALLITRICHACEAE, 311 



Not aquatics. 



Style (if any) 1 and stigma 1. 



Flowers unisexual; ovary of the fertile flowers 1 -celled 



33. URTICACEAE, 144 

 Flowers perfect ; pod 2-celled and 2-seeded, Lepidium in 



48. CRUCIFERAE, 207 



Styles 23, or branched; ovary 1 4-celled. 

 Ovary and pod 3-celled; juice usually milky 



64. EUPHORBIACEAE, 308 



Ovary not 3-celled; juice not milky. 



Flowers in an involucrate head; fruit a 3-angled 



achene, Eriogonum in 36. POLYGONACEAE, 147 



Flowers not involucrate. 



Leaves cohered, at least beneath, with stellate 



hairs 64. EUPHORBIACEAE, 308 



Leaves without stellate hairs. 

 Leaves opposite. 



Plant fleshy, Salicornia in 37. CHENOPODIACEAE, 160 



Plant not fleshy. 



Flowers in heads or spikes ; anthers 1-celled 



38. AMARANTHACEAE, 170 

 Flowers sessile in forks of branching in- 

 florescence, Paronychia in 



42. CARYOPHYLLACEAE, 180 

 Leaves alternate. 



Flowers and bracts scarious 38. AMARANTHACEAE, 170 

 Flowers chiefly greenish, no scarious bracts 



37. CHENOPODIACEAE, 160 

 Shrubs or trees. 

 Leaves opposite. 



Fruit 3-celled, not winged 70. RHAMNACEAE, 314 



Fruit winged. 



Fruit 2-celled, a double samara 69. ACERACEAE, 313 



Fruit 1-celled, a single samara 91. OLEACEAE, 378 



Leaves alternate. 



Ovary 3-celled 70. RHAMNACEAE, 314 



Ovary 1-celled 31. ULMACEAE, 143 



