Complex sentence: The tree was distinguished by its very dark green foliage, was occasionally listed as'Nigrescens', causing confusion with a "U. minor" cultivar of that name Green, P. S. (1964).
Split into simpler sentences: The tree was distinguished by its very dark green foliage. Occasionally listed as'Nigrescens', it caused confusion with a "U. minor" cultivar of that name Green, P. S. (1964).