Harmony among endemic littoral plants and adjacent floras in Israel.

The littoral belt of the Israeli Coastal Plain contains 47 taxa of endemic plants (43 species, 4 subspecies). Actual distribution of endemic plant species among families was compared to an expected distribution of endemics per family to distinguish between possible alternative patterns: 1) a 'proportional', or harmonic representation of endemics, in which the number of endemics per family reflects family diversity in potential source floras; or 2) a 'reticulate' pattern in which certain genera or families are statistically over-represented in the endemic assemblage. Analysis indicates a proportional pattern, with a high degree of harmony between the assemblage of littoral endemics and nearby floras that probably have served as evolutionary sources for most of the endemics. There was, however, a significant difference between observed and expected distribution of endemics by growth form, with too many annual and too few perennial endemics. Similarly, within the endemic assemblage, several genera presented a more reticulate pattern suggesting possible adaptive radiation. -from Authors