ABSTRACT
Achenes 3-4 mm long.............................................. 36. T. macroceras. + Cornicles 1-1.5 mm long. Achenes 4.5-5 mm long.........................11. 11. Broadened section of achene covered almost from base with subacute
spines................................................................................ 30. T. lenense. + Broadened section of achene with acute spines only in upper 1/3,
with subobtuse tubercles below.............................. 56. T. taimyrense. 12. Outer bracts of involucre lanceolate or lanceolate-linear, light green
.......................................................................................40. T. officinale. + Outer bracts of involucre lanceolate to broad-ovate.......................13. 13. Outer bracts of involucre light green. Rostrum of ripe achenes 1.5-2
times longer than broadened section of achene.......... 16. T. croceum. + Outer bracts of involucre dark green. Rostrum of ripe achenes gene
rally almost as long as broadened section of achene, rarely not more than 1.5 times longer..........................................................................14.
