Chapter XIV., the reader should consult Dale "On certain

Outgrowths (Intumescences) on the green parts of Hibiscus," _Proc. Cambr. Phil. Soc._, Vol. X., 1899, p. 192, and _Brit. Ass. Rep._, Bradford, 1900.

The detailed study of the anatomy and histology of Galls has been recently undertaken by Küster, "_Beitrage zur Kenntniss der Gallenanatomie_," Flora, B. 87, 1900, p. 117, where the principal references will be found.

On the root-galls due to Nematodes see Atkinson in _Science Contributions from the Agric. Expt. Station, Alabama_, Vol. I., p. 1, 1889; Percival, "An Eel-worm disease of Hops" in _Natural Science_, Vol. VI., 1895, p. 187; and Molliard in _Revue générale de Botanique_, Apl., 1900, p. 157, where the histology is dealt with.

The nodules of the roots of Leguminoseae are not part of the subject of this work: the literature is collected in _Science Progress_, 1895, Vol. III., p. 252, and Dawson, _Phil. Trans._, 1900.