Calyptridium parryi var. martirense is described as new. Here we present quantitative measurements and statistical analyses of a number of morphological features that demonstrate the distinctiveness of this new taxon. The new variety differs from the others in having shorter fruits (3.1–4.1 mm) and a correspondingly smaller fruit length to sepal length ratio (1.0–1.4). The capsule is also the widest (1.4–2.2 mm) and the sepals the longest (2.4–3.9 mm) of any other C. parryi variety. Calyptridium parryi var. martirense is currently known only from high elevation locations (1900–2630 m) in the Sierra de San Pedro Mártir, Baja California, Mexico.