[4b] The Student’s Flora of the British Islands, 3rd ed., 1884, p. 191.

[5] I was led to examine them by a writer in The Times (6th February 1918), who describes the buds as being as blue “as wood-smoke from cottage chimneys.”

[6] Ludwig has seen creatures, which run on the surface of the water, carry away duckweed pollen. These fertilisers belong to the families Hydrometridæ, Corisidæ, and Naucoridæ.

[7] This, and part of what follows, is from unpublished notes of lectures given at Cambridge.

[11] The present discussion is partly taken from my introduction to Blomefield’s Naturalist’s Calendar, 1903.

[12a] Observations in Natural History, p. 334.

[12b] Earliest date noted, 21st April; latest, 8th May.

[12c] Earliest date, 21st March; latest, 7th May (fifteen years’ observation).

[12d] Quoted in Prior’s Popular Names of British Plants, 3rd ed., 1879, p. 59.

[15] Reprinted from the Cornhill Magazine, June 1919.