Published in Journal of the Arnold Arboretum, in 1950, in volume 31, pages 39-80

Published in Journal of the Arnold Arboretum, in 1950, in volume 31, pages 81-116

Published in Journal of the Arnold Arboretum, in 1950, in volume 31, pages 137-171

Published in Journal of the Arnold Arboretum, in 1950, in volume 31, pages 214-240

Published in Journal of the Arnold Arboretum, in 1950, in volume 31, pages 241-263

Published in Journal of the Arnold Arboretum, in 1950, in volume 31, pages 405-429

Published in Journal of The Arnold Arboretum, in 1950, in volume 31, issue 4, pages 430-432

Published in Journal of The Arnold Arboretum, in 1950, in volume 31, issue 4, pages 437-447