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Adaptation in Clarkia, Section Myxocarpa
- Small, Ernest
- Ecology 1972 v.53 no.5 pp. 808-818
- Clarkia, annuals, diploidy, drought, gardens, habitats, leaves, photosynthesis, phylogeny, seeds, soil, temperature, transpiration
- The adaptive relationships of the eight diploid taxa of Clarkia, section Myxocarpa, are documented. The phylogeny of these taxa is well understood, allowing precise comparisons of the state of adaptiveness between related taxa in relationship to differences in their habitats. The habitats of these taxa comprise distinctive combinations of precipitation, temperature, and soil characteristics. Differences between the taxa were found with respect to rates of maturation, photosynthesis, transpiration, and leaf characteristics, all of these apparently adaptive in relation to drought. The two populations from the most unfertile soils produced the smallest seeds in a standard garden, and it is suggested that small seeds may be advantageous in annual plants in an unfertile substrate when droughts depauperize and decimate the population.