Published in Botanical Museum Leaflets, Harvard University, in 1951, in volume 14, pages 181-214

Published in Botanical Museum Leaflets, Harvard University, in 1951, in volume 14, pages 215-239

Published in Botanical Museum Leaflets, Harvard University, in 1951, in volume 14, pages 240-261

Published in Botanical Museum Leaflets, Harvard University, in 1951, in volume 14, pages 263-291

Published in Botanical Museum Leaflets, Harvard University, in 1951, in volume 15, pages 79-109

Published in Botanical Museum Leaflets, Harvard University, in 1951, in volume 15, issue 4, pages 29-78