Bronn, H. G.—'Charles Darwin, über die Einrichtungen zur Befruchtung britischer und ausländischer Orchideen.' With an Appendix by the Translator on Stanhopea devoniensis. Stuttgart, 1862.
Gray, Asa.—On Platanthera (Habenaria) and Gymnadenia in 'Enumeration of Plants of the Rocky Mountains.'—American Journal of Science and Arts, Second Series, vol. xxxiv., No. 101, Sept. 1862, p. 33.
Gray, Asa.—On Platanthera hookeri, in a review of the first edition of the present work.—American Journal of Science and Arts, vol. xxxiv. July 1862, p. 143.
Anderson, J.—'Fertilisation of Orchids.'—Journal of Horticulture and Cottage Gardener, April 21, 1863, p. 287.
Gosse, P. H.—'Microscopic Observation on some Seeds of Orchids.'—Journal of Horticulture and Cottage Gardener, April 21, 1863, p. 287.
Gray, Asa.—On Platanthera (Habernaria) flava and Gymnadenia tridentata.—American Journal of Science and Arts, vol. xxxvi. Sept. 1863, p. 292.
Journal of Horticulture and Cottage Gardener.—March 17, 1863, p. 206. 'On Orchid Cultivation, Cross-breeding, and Hybridising.'
Scudder, J. H.—On Pogonia ophioglossoides. Proceedings of the Boston Society of Natural History, vol. ix. April, 1863.
Treviranus.—'Ueber Dichogamie nach C. C. Sprengel und Ch. Darwin. § 3. Orchideen.'—Botanische Zeitung, No. 2, 1863, p. 9.