This paper describes the petrography and organic geochemistry of Taxodiaceae wood and bark tissues within Paleocene lignites of southern Saskatchewan, Canada. The wood (secondary xylem) tissues are dominated by ulminite, which fluoresces and is solely low-reflecting (dark) variety A. R(0) values are from 0.20 to 0.22%. The wood tissues are relatively hydrogen-rich and oxygen-poor, have depressed T-max values (374-380 degrees C), and are rich in methoxyphenol compounds. The bark tissues are more heterogeneous in maceral and tissue compositions. They are dominated by interlayered cork (periderm) and "A/B" (secondary phloem) tissues, the latter consisting of an intimate association of ulminite A and high-reflecting (light) ulminite B. R(0) values are from 0.24 to 0.27% for ulminite A and 0.36 to 0.44% for ulminite B. The bark tissues are relatively hydrogen-poor and oxygen-rich and have higher T-max values (403-418 degrees C), and phenols are the dominant compounds. The study provides unequivocal evidence of a plant tissue origin for the A (dark) and B (light) varieties of humotelinite macerals and reveals fundamental problems in the A vs B classification. The existence of the humotelinite A and B varieties has significant implications for the use of R(0) as a rank parameter, and these implications are discussed.