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.