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. Saucaceae ISo 

 II, Calyx present at least in the stanainate or in the perfect flowers. 



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



Plant not parasitic; fruit a nut or an achene. 



Staniinate 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 caljTc. 



32. BETUL.\rEAE 202 



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

 calyx; pistillate flowers with a calyx. 



33. Corylaceab 205 

 Staminate flowers in aments; pistfllate ones often solitary. 



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



31. Fagace-\e 199 

 Fnut drupaceous, not enclosed in a cup or bur. 



(Garrya in) 95. Cornaceae. 634 



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



2, FlowerSj at least the stanainate, not in aments. 



a. Ovary superior. 



Gynoecium of 1, or several and distinct carpels; stig^ma 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. CORRIGIOLACEAE. 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 gjmoecium; calyx corolla— like ; 



herbs. 40. Nyctaglniaceae 255 



Stamens borne on the hypanthimn or adnate to the calyx- 

 tube; calyx not corolla-like; shrubs. 

 Hj^anthium becoming fleshy in fruit, enclosing the 

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

 leaves silvery-scurfy. 89. E L^veagnace AE 581 



Hypanthium not becoming fleshy; achenes tafled; 

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

 Cercocarpus in) 60. Rosaceae 399 



Carpels several. 



Stamens inserted below the ovary. 



(Genera in) 48. Ranuxculaceae 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. 



Stipifles herbaceous; inflorescence spicate or racemose; 

 leaf-blades palmately veined. 



35. CaNNABIXACEAE 207 



Stipules scarious, or hyaline, or none: inflorescence 



cj'mose: leaf-blades pinnately veined. 

 Fruit a utricle, or achene, circimiscissile or bursting 



irregularly. 

 Stipules wanting. 



Flowers subtended by an involucre formed 

 by more or less united bracts. 



37. POLYGONACE.AE 210 



Flowers not involucrate. 

 Bracts not scarious. 



38. Chenopodiace-AE 239 



Bracts scarious. 39. Amaranthaceae 253 



Stipules present, scarious. 



43. CORIlIGIOLACE.\E 267 



