Polemonium chartaceum is a rare species of flowering plant in the phlox family known by the common names Mason's Jacob's-ladder and Mason's sky pilot. It is native to California, where it has a disjunct distribution. It occurs in the Klamath Mountains as well as the ranges east of the Sierra Nevada, including the White Mountains, where its distribution extends just into Nevada. It is a plant of high elevations, growing in exposed, rocky mountain slope habitat such as talus and alpine fellfields.