MORPHOLOGICAL VARIATION IN FRAGARIA VIRGINIANA FROM THE ROCKY MOUNTAINS
Fragaria virginiana plants from 37 sites in the northern Rocky Mountains (USA) were grown in a greenhouse and characterized for ten leaf traits to discern whether any patterns of morphological variation existed in relation to environmental or geographical factors. Four principal components (PC) explained 88% of the total variance among the 37 collections. The first PC was a multivariate measure of leaf size that accounted for 55% of the total variance. Two groups of collections could be distinguished by relating PC1 to geographical or environmental factors. The first group included collections from the Black Hills (South Dakota), an eastern outpost of Rocky Mountain flora. This group had high values of PC1 indicating large leaf size which suggested influence of the eastern F. virginiana ssp. virginiana. Collections from further west in Montana, Wyoming and Idaho were more typical of the smaller-leaved F. virginiana ssp. glauca. Among populations even in this western group, collections from high elevations (> 2000 m) had smaller multivariate leaf size, which may represent an adaptation to high light intensity and extreme temperatures.
Hokanson, Karen E., Harrison, R. E., Luby, James J. and Hancock, James F. (1993). MORPHOLOGICAL VARIATION IN FRAGARIA VIRGINIANA FROM THE ROCKY MOUNTAINS. Acta Hortic. 348, 94-101