FLOWERING PLANTS AND FERNS OF ARIZONA 51 



11. Petals 10 or fewer, usually not more than 5; stems not succulent or only 

 moderately so; leaves well developed (12). 

 12. Flowers in umbels or dense round heads, very small (13). 



13. Fruit a several-seeded berry 90. Araliaceae. 



13. Fruit dry, of 2 closely contiguous carpels, these 1-seeded. 



91. Umbelliferae. 

 12. Flowers not in umbels or dense round heads, if the inflorescence sub- 

 capitate, then the plant armed with barbed stinging hairs (14). 



14. Herbage very rough-pubescent, the hairs commonly barbed, some- 



times stinging 84. Loasaceae. 



14. Herbage not rough-pubescent, or the hairs not barbed (15). 

 15. Stems herbaceous or merely suffrutescent (16). 



16. Plants aquatic; leaves (or some of them) finely dissected; 



flowers minute 89. Haloragidaceae. 



16. Plants not aquatic or, if so, then the flowers showy; leaves simple, 

 sometimes pinnatifid (17). 

 17. Stems and leaves more or less succulent; fruit a circumscissile 



capsule: Genus Portulaca 39. Portulacaceae. 



17. Stems and leaves not succulent; fruit not circumscissile (18). 

 18. Styles 2 or 3; stamens 5 or 10; ovary of 2 or 3 partly separate 



carpels 50. Saxifragaceae. 



18. Style 1; ovary entire (19). 



19. Stamens commonly 4 or 8 (seldom only 2); fruit a 2- to 

 5-celled capsule, or sometimes indehiscent and nut- 

 like , 88. Oxagraceae. 



19. Stamens 3; fruit 1-celled, large and gourdlike: Genus 



Apodanthera 119. Ctjcurbitaceae. 



15. Stems woody (20). 



20. Fruit dry, follicular or capsular (21). 



2 1 . Stamens 8 or more 50. Saxifragaceae. 



21. Stamens 5 or fewer 71. Rhamxaceae. 



20. Fruit a more or less fleshy drupe, pome, or berry (22) . 



22. Flowers small, in many-flowered compound cymes; leaves 



simple, entire; fruit a drupe, the stone containing 1 or 2 

 seeds; calyx limb minute: Genus Cornus. 



92. Corxaceae. 



22. Flowers in relatively few-flowered racemes or corymbs or, if 



in many-flowered compound cymes, then the leaves 



pinnate; fruit several-seeded; calvx limb well-developed 



(23). 



23. Leaves palmately lobed; stamens not more than 5; fruit a 



berry: Genus Ribes 50. Saxifragaceae. 



23. Leaves not palmately lobed, simple or pinnate; stamens 

 numerous; fruit a pome (the carpels embedded in the 



thickened receptacle) 53. Rosaceae. 



10. Ovary superior, free from the calyx or very nearly so (24) . 

 24. Anthers opening by terminal valves or pores (25). 



25. Plants shrubs or undershrubs; leaves compound; stamens 6; ovary 



1-celled 43. Berberidaceae. 



25. Plants herbaceous or nearly so; leaves simple; stamens 8 or more; 

 ovary several-celled (26). 

 26. Flowers with petals of unequal width and stamens dimorphic; leaf 

 blades palmately cleft or parted; stems from^ large tuberlike 



root; stamens numerous 80. Cochlospermaceae. 



26. Flowers regular or very nearly so; leaf blades not lobed (sometimes 

 reduced to scales and the plant without chlorophyll") ; root not 



tuberlike; stamens 8 to 10 94. Ericackak. 



24. Anthers opening longitudinally (27). 



27. Flowers very numerous in dense globose heads; plant a tree; leaves 



large, palmately lobed 51. Plataxaceak. 



27. Flowers not in dense globose heads, or the plant not a tree with pal- 

 mately lobed leaves (28). 

 28. Flowers with a more or less thickened disk surrounding or under the 

 ovary or ovaries, this often bearing the stamens, or the stamens 

 numerous and borne in one or more circles on the throat of the 

 calyx (29). 



