Published in Journal of the Arnold Arboretum, in 1968, in volume 49, pages 35-40

Published in Journal of the Arnold Arboretum, in 1968, in volume 49, pages 41-51

Published in Journal of the Arnold Arboretum, in 1968, in volume 49, pages 278-279

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 1, pages 16-34

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 1, pages 52-72

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 1, pages 73-166

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 2, pages 167-192

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 2, pages 193-224

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 2, pages 225-232

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 2, pages 233-258

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 2, pages 258-259

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 2, pages 260-277

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 2, pages 280-289

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 3, pages 317-332

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 3, pages 333-369

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 3, pages 370-376

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 3, pages 377-379

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 4, pages 419-430

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 4, pages 431-501

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 4, pages 502-508

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 4, pages 509-524

Published in Journal of The Arnold Arboretum, in 1968, in volume 49, issue 4, pages 525-544