Physaria scrotiformis O'Kane (Brassicaceae) is a newly described, diminutive, long-lived perennial from the upper subalpine–lower alpine zone of the San Juan Mountains of southwestern Colorado. The species grows on windswept, nearly barren exposures of Leadville limestone on West Silver Mesa. The species is another example of a taxon bridging the gap between the synonymized genera Lesquerella S. Watson and Physaria (Nuttall ex Torrey & A. Gray) A. Gray s. str. Additionally, the following new combinations and changes in status are made and keys are provided where needed: P. carinata (Rollins) O'Kane & Al-Shehbaz subsp. paysonii (Rollins) O'Kane, P. carinata (Rollins) O'Kane & Al-Shehbaz subsp. pulchella (Rollins) O'Kane, P. didymocarpa (Hooker) A. Gray subsp. lanata (A. Nelson) O'Kane, P. didymocarpa (Hooker) A. Gray subsp. lyrata (C. L. Hitchcock) O'Kane, P. floribunda Rydberg subsp. osterhoutii (Payson) O'Kane, P. geyeri (Hooker) A. Gray subsp. purpurea (Rollins) O'Kane, P. hitchcockii (Munz) O'Kane & Al-Shehbaz subsp. confluens (Maguire & A. H. Holmgren) O'Kane, P. kingii (S. Watson) O'Kane & Al-Shehbaz subsp. kaibabensis (Rollins) O'Kane, P. kingii (S. Watson) O'Kane & Al-Shehbaz subsp. utahensis (Rydberg) O'Kane, P. lepidota Rollins subsp. membranacea (Rollins) O'Kane, P. newberryi A. Gray subsp. yesicola (R. C. Sivinski) O'Kane, and P. saximontana Rollins subsp. dentata (Rollins) O'Kane.