R.  Schlechter, ?Orchideologiae sino-japonicae prodromus. Eine kritische Besprechung der Orchideen Ost-Asiens?, Repertorium specierum novarum regni vegetabilis. Beihefte, vol. 4, pp. 1 - 319, 1919.

M. M.  Denis, ?Surquelques thalles d' Aneura dépourvus de chlorophylle?, Comptes rendus hebdomadaires des séances de l'academie des sciences, vol. 168, pp. 64 - 66, 1919.

M. W.  Henderson, ?A comparative study of the structure and saprophytism of the Pyrolaceae and Monotropaceae with reference to their derivation from the Ericaceae?, Contr. Bot. Lab. Morris Abor. Univ. Pennsylvania, vol. 5, pp. 42 - 109, 1919.

P. C.  Standley, ?The Panamanian species of Leiphaimos?, Contr. U.S. Natl. Herb., vol. 20, pp. 194 - 200, 1919.