Article from Bean's Trees and Shrubs Hardy in the British Isles
Recommended citation
'Luetkea' from the website Trees and Shrubs Online (treesandshrubsonline.
A genus of a single species in western N. America, allied to Spiraea, but differing in the much-segmented leaves, filaments of stamens united at the base and follicles splitting along both edges. For the derivation of the generic name, see below.