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In the Chihuahuan desert, the distribution of the poikilohydric resurrection plant, Selaginella lepidophylla (Hook. and Grev.) Spring. (Selaginellaceae, spikemoss family), is restricted by aspect and the presence of other vascular plants. Few individuals arc found on south-facing slopes, and the density of S. lepidophylla is highly correlated with the cosine of aspect. Multiple linear regression demonstrated that a four-variable model best explained changes in the density of S. lepidophylla on north-facing slopes, with total cover of other plants being the most important variable. Abiotic parameters may indirectly restrict S. lepidophylla by controlling the presence of other vascular plants. A five-variable regression model showed that rock cover was the most important factor explaining changes in other vascular plant cover. Selaginella lepidophylla appears to be a colonizer, and its distribution may be limited by effects of high temperature and competition with vascular plants for light or soil resources.