STANDLEY TREES AND SHRUBS OF MEXICO. 31 



G. Leaves stipulate. 



Stamens twice as many as the petals or more. 

 Styles 2 to 5. 



Styles 2 ; stamens 8 to 12 ; leaves compound, usually opposite. 



CTJNONIACEAE. 

 Styles 5 ; stamens usually numerous ; leaves simple or com- 

 pound, alternate ROSACEAE. 



Style 1, simple or bilobulate. 



Leaves compound ; stamens 8 to 10 ZYGOPHYLLACEAE, 



Leaves simple; stamens usually numerous. 



Stamens inserted on a disk ; ovules numerous ; leaves oppo- 

 site or alternate ELAEOCAEPACEAE. 



Stamens inserted on the calyx tube; ovules 2 in each coll; 



leaves opposite, entire RHIZOPHORACEAE. 



Stamens as many as the petals or fewer. 



Stamens as many as the petals and opposite them. Vines with 



tendrils ; leaves alternate VITACEAE. 



Stamens as many as the petals and alternate with them, or 

 fewer. 

 Leaves compound. Flowers perfect. 



Ovary 2 to 4-lobate ; seeds without endosperm. 



SAPINDACEAE. 

 Ovary 3-celled ; seeds with endosperm_STAPHYLEACEAE. 

 Leaves simple. 



Style 1, simple ; ovules erect or ascending ; flowers usually 



perfect CELASTRACEAE. 



Style 1 and divided, or styles 3 ; ovules pendulous or in- 

 verted ; flowers unisexual EUPHORBIACEAE. 



G. Leaves estipulate. 

 Leaves simple; disk present or absent. 



Leaves alternate. .Stamens 2 to 10, twice as many as the petals 

 or fewer. 

 Stamens 5, opposite the petals, only 2 of them fertile. Ovary 



2-cened, each cell with 2 ovules SABIACEAE. 



Stamens 3 to 10, alternate with the petals, or less or more 

 numerous. 



Leaves with translucent glands RITTACEAE. 



Leaves without glands CELASTRACEAE. 



Leaves opposite or whorled. 



Stamens 3, less numerous than the petals. Leaves entire. 



HIPPOCRATEACEAE. 

 Stamens as many as the petals or more numerous. 

 Ovules 2 in each cell. 



Ovary 2-celled; leaves without translucent glands. Fruit 



a double samara ^_ACERACEAE. 



Ovary 3 to 5-celled ; leaves with translucent glands. 



RUTACEAK 

 Ovules more than 2 in each cell. 



Styles or stigmas 5 to 10 ; leaves entire CLUSLACEAE. 



Style 1, simple. 

 Calyx lobes imbricate or open in bud ; leaves with lon- 

 gitudinal ribs— MELASTOMATACEAE. 



• Calyx lobes valvate ; leaves not ribbed _LYTHRACEAE. 



