Characteristics: Terrestrial ferns; stipes tuft, backlish at base; young fronds pinnaye with wider pinnae, when getting older, the fronds become bipinnate or tripinnatifid with slender pinnules.
The ubiquity of phenanthrene series, chrysene series compounds, perylene and retene compounds in the sediment indicated that PAHs mainly came from the terrestrial plants.
Left on their own, reindeer can wander farther than any other terrestrial mammal, about 5000 kilometers a year, and reach speeds about to 80 kilometers per hour.