I. M.  Johnston, ?The coastal flora of the departments of Chañaral and Taltal?, Contributions from the Gray Herbarium of Harvard University, vol. 85, pp. 1 - 138, 1929.

I. M.  Johnston, ?The flora of the Nitrate Coast?, Contributions from the Gray Herbarium of Harvard University, vol. 85, pp. 138 - 163, 1929.

I. M.  Johnston, ?New records for the flora of the Nitrate Coast?, Revista Chilena de Historia Natural, vol. 36, pp. 4 - 8, 1932.

I. M.  Johnston, ?Studies in the Boraginaceae, XIII. New or otherwise noteworthy species, chiefly from western United States?, Journal of the Arnold Arboretum, vol. 20, pp. 375 - 402, 1939.

I. M.  Johnston, ?Studies in the Boraginaceae XX. Representatives of three subfamilies in eastern Asia?, Journal of the Arnold Arboretum, vol. 32, pp. 99 - 122, 1951.

I. M.  Johnston, ?Some noteworthy American Borages?, Wrightia, vol. 2, pp. 13 - 22, 1959.

I. M.  Johnston, ?Studies in the Boraginaceae VII. The South American species of Heliotropium?, Contributions from the Gray Herbarium of Harvard University, vol. 81, pp. 3 - 73, 1928.

I. M.  Johnston, ?Studies in the Boraginaceae XII. 2. Novelties and critical notes?, Journal of the Arnold Arboretum, vol. 18, pp. 10 - 25, 1937.

I. M.  Johnston, ?Boraginaceae. in: Steyermark. J. A. and collaborators: Contributions to the flora of Venezuela?, Fieldiana, Botany, vol. 28, pp. 1080 - 1082, 1957.

I. M.  Johnston, ?Studies in the Boraginaceae VIII. I. Observations on the species of Cordia and Tournefortia known from Brazil. 3. Treatment of Tournefortia?, Contributions from the Gray Herbarium of Harvard University, vol. 92, pp. 66 - 89, 1930.

I. M.  Johnston, ?Studies in the Boraginaceae XI. 1. The species of Tournefortia and Messerschmidia in the Old World?, Journal of the Arnold Arboretum, vol. 16, pp. 145 - 168, 1935.

I. M.  Johnston, ?Studies in the Boraginaceae X. The Boraginaceae of Northeastern South America?, Journal of the Arnold Arboretum, vol. 16, pp. 1 - 64, 1935.

I. M.  Johnston, ?Studies in the Boraginaceae XVIII. Boraginaceae of the southern West Indies?, Journal of the Arnold Arboretum, vol. 30, pp. 111 - 138, 1949.