Intraspecific variation in blackbrush (Coleogyne ramosissima Torr.) seed imbibition was quantitatively investigated in the Mojave Desert. Blackbrush seeds were collected from six isolated mountain ranges, with each range sampled from one high-elevation (1550 m) and one low-elevation (1200 m) location for a total of 12 populations. Under laboratory experimental conditions, seed dry mass and initial seed moisture content did not differ significantly among the 12 populations. High-elevation source seeds imbibed significantly more water than low-elevation source seeds, and this was likely associated with habitat-specific selection. However, differences in full imbibition among seed collection sites at the identical elevation were not significant. Germination of field-collected seeds was similar, ranging from 87 to 93% among the 12 populations. Results of this study suggest that among six isolated mountain ranges in the Mojave Desert, blackbrush seed imbibition varies with elevation, but not with latitude.