STANDLEY TREES AND SHRUBS OF MEXICO. 25 



Style 1, simple or cleft only at the apex, or stigiiia 1 and sessile. 

 Petals valvate in bud. 



Stamens 8 to 10, twice as many as the petals; calyx lobes valvate 



in bud ; leaves alternate' or opposite COMBRETACEAE. 



Stamens 2 to 6, as many as the petals or fewer; calyx lobes open or 



imbricate in bud; leaves alternate OLACACEAE. 



Petals imbricate or contorted in bud. 



Ovary 1-celled, the ovules suspended from the apex of the cell. 



COMBRETACEAE. 

 Ovary 1-celled, with basal, central, or parietal ovules, or several- 

 celled. 

 Ovary 4 or 5-celled. 



Perfect stamens 10; leaves opposite MYRTACEAE. 



Perfect stamens 5; leaves alternate__PTEROSTEMONACEAE. 

 Ovary 1-celled, or incompletely several-celled. 



Anthers dehiscent by terminal pores ; leaves usually with loni?i- 



tudinal ribs, opposite MEIiASTOMATACEAE. 



Anthers dehiscent by longitudinal slits; leaves without longitu- 

 dinal ribs. 

 Seeds with endosperm ; petals imbricate or open in bud ; 



fruit baccate; leaves alternate GROSSULARIACEAE. 



Seeds without endosperm; petals contorted; fruit capsular: 



leaves alternate or opposite ONAGRACEAE. 



BB. Perfect stamens more than 10. 



Style 1, simple or cleft only at the apex, or stigma 1 and sessile. 



Leaves stipulate. Leaves opposite, entire RHIZOPHORACEAE. 



Leaves estipulate. * 



Plants very succulent and spiny, the leaves usually absent. 



CACTACEAE. 

 Plants neither succulent nor spiny ; leaves well developed. 



Stamens usually twice as many as the petals : leaves usually with 



longitudinal ribs MELASTOMATACEAE. 



Stamens more than twice as many as the petals ; leaves without lon- 

 gitudinal ribs. 

 Sepals 2 to 4, or more and imbricate; leaves usually punct;it(\ 



MYRTACEAE. 



Sepals 5 to 8, valvate; leaves not punctate PUNICACEAE. 



Styles 2 or more, free or united only at the base, or the stignuis 2 or UK^re 

 and sessile. 

 Leaves estipulate, opposite. 



Flowers borne upon the leaves ; petals valvate in bud. 



ESCALLONIACEAE. 

 Flowers not borne upon the leaves; petals valvate or imbricate. 



HYDRANGEACEAE. 

 Leaves stipulate, alternate. Petals imbricate in bud. 



Ovary 1-celled ; petals usually 6 to 8 FLACOURTIACEAE. 



Ovary several-celled; petals 5 MALACEAE. 



AA. Ovary superior or nearly so. 



C. Ovary 1, 1-celled or incompletely several-celled. 



Sepals 2, distinct or rarely connate and forming a cap. Leaves estipulate. 



Leaves entire; plants with colorless juice PORTULACACEAE. 



Leaves dentate or lobate; plants with colored juice__PAPAVERACEAE. 



