KEY TO THE FAMILIES 3 



Fruit a nut or an achene. 33. CORYLACEAE 205 



Fruit a drupe or a samara. 101. OLEACEAE 655 



Fruit many-seeded; seeds each with a tuft of hairs. 



30. SALICACEAE 185 

 II. Calyx present at least in the staminata or in the perfect flowers. 



1. Flowers, at least the staminate, in aments or ament-like spikes. 



Plant not parasitic; fruit a nut or an achene. 



Staminate and pistillate flowers both in aments; fruit not with a bur 



or cup. 



Staminate flowers 2 or 3 together in the axils of the bracts, each 

 with a calyx; pistillate flowers without a calyx. 



32. BETULACEAE 202 

 Staminate flowers solitary in the axils of each bract, without a 



calyx; pistillate flowers with a calyx. 



33. CORYLACEAE 205 

 Staminate flowers in aments; pistillate ones often solitary. 



Fruit a nut, at least partly enclosed in a cup or bur. 



31. FAGACEAE 199 

 Fruit drupaceous, not enclosed in a cup or bur. 



(Garrya in) 95. CORNACEAE. 634 



Plant parasitic; fruit berry-like. 125. LORANTHACEAE 816 



2. Flowers, at least the staminate, not in aments. 



a. Ovary superior. 



Gynoecium of 1, or several and distinct carpels; stigma and style of 

 each solitary. 



Carpel solitary. 



Ovary neither enclosed nor seated in a hypanthium or a calyx- 

 tube. 



Flowers not solitary in the axils of the leaves; land plants. 

 Plants with scarious stipules; flowers cymose. 



43. CORKIGIOLACEAE. 267 



Plants not with scarious stipules; flowers clustered. 



36. URTICACEAE 208 

 Flowers solitary in the axils of the leaves; aquatic plants. 



46. CERATOPHYLLACEAE 284 



Ovary enclosed in or seated in a hypanthium or a calyx-tube. 

 Stamens borne under the gynoecium; calyx corolla like; 



herbs. 40. NYCTAGINIACEAE 255 



Stamens borne on the hypanthium or adnate to the calyx- 

 tube; calyx not corolla-like ; shrubs. 

 Hypanthium becoming fleshy in fruit, enclosing the 

 tail-less achenes; calyx 4-merous; stamens 4 or 8; 

 leaves silvery-scurfy. 89. ELAEAGNACEAE 581 



Hypanthium not becoming fleshy; achenes tailed; 

 calyx 5-merous; leaves not scurfy. (Coleogyne and 

 Cercocarpus in) 60. ROSACEAE 399 



Carpels several. 



Stamens inserted below the ovary. 



(Genera in) 48. RANUNCULACEAE 285 

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



(Genera in) 60. ROSACEAE 399 



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

 Ovary, by abortion, 1-celled and 1-ovuled. 



Leaves with sheathing stipules (ocreae). 



37. POLYGONACEAE 210 



Leaves estipulate, or stipules, if present, not sheathing. 

 Trees or shrubs; ovary not seated in a hypanthium. 



34. ULMACEAE 206 

 Herbs or vines. 



Stipules herbaceous; inflorescence spicate or racemose; 

 leaf-blades palmately veined. 



35. CANNABINACEAE 207 

 Stipules scarious, or hyaline, or none; inflorescence 



cymose: leaf-blades pinnately veined. 

 Fruit a utricle, or achene, circumscissile or bursting 



irregularly. 

 Stipules wanting. 



Flowers subtended by an involucre formed 

 by more or less united bracts. 



37. POLYGONACEAE 210 

 Flowers not involucrate. 



Bracts not scarious. 



38. CHENOPODIACEAE 239 

 Bracts scarious. 39. AMAHANTHACEAE 253 



Stipules present, scarious. 



43. CORRIGIOLACEAE 267 



