5. Tiedemannia. Dorsal ribs apparently 5, filiform. Smooth swamp herbs with leaves few or reduced to hollow cylindrical petioles. 6. Heracleum. Dorsal ribs filiform, the broad wings with a marginal nerve. Oil-tubes obclavate. Petals conspicuous. Tall stout perennials, with large leaves. [+][+] Caulescent branching plants, with depressed stylopodium and yellow flowers. 7. Pastinaca. Fruit with filiform dorsal ribs, thin wings, and solitary oil-tubes. 8. Polytænia. Fruit with a thick corky margin, obscure dorsal ribs, and very numerous oil-tubes. [+][+][+] Acaulescent or nearly so, with filiform dorsal ribs, thin wings, and no stylopodium. 9. Peucedanum. Flowers white or yellow. Low western plants, of dry ground, with thick roots and finely dissected leaves. [*][*] Fruit not flattened either way or but slightly, neither prickly nor scaly. [+] Ribs all conspicuously winged; stylopodium depressed or wanting. 10. Cymopterus. Low and glabrous, mostly cespitose perennials, with pinnately compound leaves and white flowers. Oil-tubes 1 to several. Western. 11. Thaspium. Tall perennials, with ternately divided or simple leaves, and yellow flowers (rarely purple). Oil-tubes solitary. [+][+] Ribs all prominent and equal but not winged; flowers white. 12. Ligusticum. Ribs acute, with broad intervals. Stylopodium conical. Oil-tubes numerous. Smooth perennials, with large compound leaves. 13. Æthusa. Ribs very broad and corky, acute. Stylopodium depressed. Oil-tubes solitary. Introduced annual. 14. Cœlopleurum. Ribs thick, corky (mostly obtuse). Oil-tubes solitary, adherent to the seed, which is loose in the pericarp. Stout glabrous sea-coast perennial. [+][+][+] Dorsal ribs filiform, the lateral very thick and corky; oil-tubes solitary. 15. Crantzia. Small glabrous creeping perennials, rooting in the mud, with small simple umbels and leaves reduced to hollow cylindrical jointed petioles. [*][*][*] Fruit flattened laterally. [+] Carpels depressed dorsally; fruit short. [++] Seed-face flat; flowers mostly yellow. 16. Fœniculum. Ribs prominent. Oil-tubes solitary. Stout aromatic herb, with filiform-dissected leaves. 17. Pimpinella. Ribs filiform. Oil-tubes numerous. Glabrous perennials, with compound leaves. [++][++] Seed-face concave; flowers white (yellow in n. 20); ribs filiform or obsolete. 18. Eulophus. Oil-tubes numerous. Stylopodium conical. Glabrous perennials from fascicled tubers, with pinnately compound leaves. 19. Anthriscus. Fruit linear, long-beaked, without ribs or oil-tubes, and with conical stylopodium. Leaves ternately decompound. 20. Bupleurum. Fruit oblong, with slender ribs, no oil-tubes, and prominent flat stylopodium. Leaves simple, perfoliate. [+][+] Carpels terete or slightly flattened laterally; flowers white (except n. 24). [++] Seed-face flat (or somewhat concave in n. 28); fruit short. [=] Leaves 3-foliolate; stylopodium conical; oil-tubes solitary.