24 ' NORTH AMERICAN FLORA [VoLUME 33 
Inflorescence leafy with numerous branches; leaf-segments 
elongate, not spreading. 11. F. confertifiora. 
Inflorescence more simple; leaf-segments short and spread- 
ing. 12. F. Pringlet. 
Stem more or less hirsute with long white hairs. 
Staminate involucre 3-5 mm. broad; plant usually green. 
Segments of the.lower leaves broad and obtuse, not divar- 
icate. 13. F. tenuifolia. 
Segments all narrow, acute and divaricate, the terminal 
one usually much elongate. 14. F. caudata. 
* Staminate involucre 2-3 mm. broad; plant more or less canes- 
cent. 
Leaf-segments narrowly linear. 15. F. hispidissima. 
Leaf-segments lanceolate. 16. F. incana. 
Leaves simply pinnatifid; fruit merely slightly glandular-granulifer- 
ous; shrubby. 17. F. acuminata. 
IV. ERIOCENTRAE 
One species. : 18. F. eriocentra. 
V. TOMENTOSAE 
One species. 19. F. tomentosa. 
VI. DISCcOLORES 
Plant not hispid. 
Leaves equally white-tomentose on both sides. 20. F. nivea. 
Leaves white-tomentose beneath, but greener above. 
Fruit strigose but scarcely glandular; plant herbaceous with a 
creeping rootstock. 21. F. discolor 
Fruit decidedly glandular-granuliferous; plant more or less woody 
at the base 
Fruit hirsute as well as glandular; leaf-segments broad. 22. F. camphorata. 
Fruit merely glandular; leaf-segments very narrow. 23. F. leptophylla. 
Plant more or less hispid. 24. F. hispida. 
VII. ALBICAULES 
‘Spines more or less flattened but rather narrow, not hooked. 
Ultimate divisions of the leaves obovate or elliptic; paleae ot the 
staminate receptacle with broad tips, villous; staminate involucre 
about 5 mm. wide. 25. F. dumosa. 
Ultimate divisions of the leaves oblong; paleae of the staminate re- 
ceptacle linear-spatulate, sparingly pubescent; staminate in- 
volucre about 3 mm. wide. 26. F. albicaulis. 
Spines almost terete, slightly grooved above, hooked at the apex. 
Leaf-segments and rachis about ’*2 mm. broad; leaves greenish 
above. 27. F. Magdalenae. 
Leaf-segments and rachis 1 mm. broad or less; leaves canescent on 
both sides. 28. F. intricata. 
VIII. CorDIFOLIAE 
Spines of the fruit distinctly channeled on the upper side, rather thin 
and narrow. 29. F. malvacea. 
Spines of the fruit if at all sulcate only slightly so at the base, thick and 
stout. 
Fruit ellipsoid, twice as long as broad; spines 15-20, thick, broadened 
at the base, in about 3 series; leaves merely lobed. 30. F. cordifolia. 
Fruit rounded, obovate, a little longer than broad; spines 25-30, 
not much broadened at the base; leaves deeply cleft. 31. F. divaricata. 
IX. ARBORESCENTES 
Spines of the fruit nearly terete, hooked at the apex. 
Leaves deeply lobed and toothed, canescent beneath. 32. F. arborescens. 
Leaves coarsely sinuately toothed, green on both sides. 33. F. Sanctae-Gertrudis. 
Spines of the fruit dilated and deeply pitted at the base, scarcely hooked 
at the apex. 34. F. flexuosa. 
X. CHENOPODIFOLIAE 
Fruit decidedly glandular-puberulent, slightly if at all villous; leaves 
narrow, acute. 
Lower spines of the fruit ovate or broadly lanceolate. 35. F. deltoidea. 
Lower spines of the fruit narrowly lanceolate or subulate. 36. F. lancifolia. 
Fruit decidedly villous, not glandular; leaves broadly ovate, usually - 
obtuse. 37. F. chenopodifolia. 
XI. AMBROSIOIDES 
One species. 38. F. ambrosioides. 
XII. ILIciFOLIAE 
One species. 39. F, ilicifolia. 
