48 MISC. PUBLICATION 4 2 3, TJ. S. DEPT. OF AGRICULTURE 



15. Stems almost none outside the bark of the host, only the flowers 



and a few imbricate bractlike leaves apparent; fruit several- 

 seeded 32. Rafflesiaceae. 



14. Plants terrestrial, autophytic, or exceptionally root-parasitic (16). 



16. Perianth very irregular, with the segments united below into a 



tube 31. Aristolochiaceae. 



16. Perianth regular or nearly so (17). 



17. Fruit of 2 partly separate beaked carpels: Genus Heuchera. 



50. Saxifragaceae. 

 17. Fruit of a single carpel (18). 



18. Ovules 2 or more; ovary truly inferior, crowned in fruit by 



the persistent perianth 30. Santalaceae. 



18. Ovule solitary; ovary technically superior, but in fruit very 

 closely enveloped by the base of the perianth tube and 

 appearing inferior (19). 

 19. Plants herbaceous or suff rutescent ; pubescence not stellate; 

 perianth campanulate, f unnelform, or salverform, usually 

 corollalike in texture; fruit dry __ 36. Nyctaginaceae. 

 19. Plants shrubby; pubescence stellate-scurfy; perianth urn- 

 shaped, not corollalike, its base fleshy in fruit. 



86. Elaeagnaceae. 

 8. Ovary superior, free or very nearly free from the perianth when the latter 

 is present (20). 

 20. Pistils commonly more than 1; stamens numerous; fruits indehiscent 

 (achenes) or longitudinally dehiscent on one suture (follicles). 



42. Ranunculaceae. 

 20. Pistil 1, simple or compound (21). 

 21. Style and (or) stigma 1 (22). 



22. Plant aquatic (the stems immersed in water) ; leaves in whorls, 



finely dissected 41. Ceratophyllaceae. 



22. Plants not aquatic, the stems not immersed (23). 



23. Fruit a circumscissile crested several-seeded capsule: Genus 



Trianthema 38. Aizoaceae. 



23. Fruit not a circumscissile several-seeded capsule (24). 

 24. Plants herbaceous (25). 



25. Fruit berrylike; flowers in terminal racemes; perianth- 

 segments 4 : Genus Rivina 37. Phytolaccaceae. 



25. Fruit not berrylike (26) . 



26. Ovary 2-celled; fruit a flat, obcordate capsule: Genus 



Le-pidium 46. Cruciferae. 



26. Ovary 1-celled; fruit a 1-seeded, indehiscent utricle or 

 achene (27). 

 27. Leaves pinnate; stamens usually 2; achene enclosed in 

 an urn-shaped, 4-winged hypanthium: Genus San- 



gaisorba 53. Rosaceae. 



27. Leaves simple; stamens usually more than 2 (28). 



28. Stipules present or absent ; inflorescences loose, axillary ; 



perianth not scarious 28. Urticaceae. 



28. Stipules none ; inflorescences dense, terminal or axillary ; 



perianth often scarious 35. Amaranthaceae. 



24. Plants shrubs or trees (29). 



29. Stamens 10 or more, or, if fewer than 10, then the leaves 

 bipinnate (30). 

 30. Leaves simple; flowers solitary or in few-flowered fascicles: 

 Genera Cercocarpus, Coleogyne 53. Rosaceae. 



30. Leaves pinnate or bipinnate; flowers in heads, spikes, or 



spikelike racemes: Subfamily Mimosoideae and genus 



Parry ella 54. Leguminosae. 



29. Stamens 5 or fewer; leaves never bipinnate (31). 



31. Ovary 4- or 5-celled; fruit a capsule; stamens 5, the fila- 



ments united below into a tube: Genus Fremontodendron. 



75. Sterculiaceae. 



31. Ovary 2-celled; fruit a samara or a drupe; stamens 2 or 4, 



separate; leaves simple or pinnate 98. Oleaceae. 



