Dichelostemma lacuna-vernalis L.W. Lenz was proposed in 1974 for populations of a diminutive Dichelostemma associated with vernal pool terrain. The author of Dichelostemma in the 1993 edition of The Jepson Manual did not accept the new species, reporting that the morphological and ecological characteristics of D. lacuna-vernalis were within the ranges for D. capitatum (Benth.) Alph.Wood. The purpose of this paper was to test the validity of D. lacuna-vernalis using a morphometric analysis of eighteen morphological characters in populations of D. capitatum and D. lacuna-vernalis sampled in the field and by comparing plants of both taxa grown under common garden conditions. The data were subjected to cluster analysis, principal components analysis, and discriminant analysis. The results of the analysis confirm the morphological distinctness of D. lacuna-vernalis and support its recognition as a separate taxon. Based on current taxonomic concepts in the Brodiaeoideae, this taxon is best recognized at subspecies rank, as D. capitatum subsp. lacuna-vernalis (L. W. Lenz) D.W. Taylor. Populations of D. capitatum subsp. lacuna-vernalis are distinguished by their short scapes (ca. 15 cm), inflorescences with one or two flowers, short (≤4 mm) perianth tubes, and outer perianth lobes that are ovate, decurrent at the base, and wider than the inner perianth lobes.