8 



FIG. 6. Distribution of S. intermedia, a, achene, X 3. FIG. 7. Distribution of S. san^ 

 fordii. a, mature pistillate flower and bracts, X 2 / 3 . b, achene, X 3. FIG. 8. North Ameri- 

 can distribution of S. montevidensis. a, b, subsp. ccdycina. a, achene, X 3. b, bracts, 

 X%. c, achene of subsp. spongiosa, X 3. 



