Read paper on Cytisus scoparius to the Linnean Society.
"More Letters of Charles Darwin" by Charles Darwin
Note on the Common Broom (Cytisus Scoparius).
"Life of Charles Darwin" by G. T. (George Thomas) Bettany
Cytisus albus (White Broom), Cytisus scoparius (Yellow Broom), and its varieties.
"Trees and Shrubs for English Gardens" by Ernest Thomas Cook