Abstract:

Where does maximum species richness exist? This frequently asked question has never been answered based on a large database. We examined about 10 000 species of seed plants in the northern portion of the Northern Hemisphere in last 10 years. The results indicate that northwestern North America has the greatest species richness in both the boreal and temperate zones. But this great species pool has the smallest family richness and tree species diversity due to relatively recent origin. Maximum species richness exhibited largely in hydrie, or occasionally in xeric, but not mesie habitats as expected. Chance is the primary factor and habitat selection is a secondary factor used to interpret this species distribution pattern.

Key words: wild rice, genetic resources, conservation, breeding, utilization