You can cut the rhizomes apart with a sharp knife, razor blade, or a pair of scissors. Then repot each separate plant as the original clump had been planted, being careful not to damage or bend the root system during repotting. Seed is rarely produced and often hard to come by, however if you do get some sow and raise the seedlings the same way that was described for the North American Pitcher Plants. Also the seeds will not require a stratification period. Young seedlings of Darlingtonia growing in pure live sphagnum moss.
Seeds require no stratification.
Also it is not required for this genus to be divided like in sarracenia and often these plants grow their best when left in large clumps. Seed is rarely produced and is not an effective way to propagate this species. In both cases the entire leaf should be used and should be cut off as close to the plant as possible. The cuttings should be taken during the summer time. Then fill a pot up with the soil that the parent plant was growing in and sprinkle a thin layer of chopped up live sphagnum moss on top.