Information Sources in the Life Sciences . H.V. Wyatt, editor. SCI REF DESK Very complete coverage of biological literature with EM on British publications. One chapter focuses on botany. A nice collection of useful resources.
Most entries are well annotated.
Fairly comprehensive listing of botany resources. Arranged by provider than by resource. Since it is comprehensive many of the resources are less than well developed. It includes the electronic versions of the Flora of North America, the Flora of Madagascar, the Flora of Mesoamerica, and the Flora of China. These are all in early stages of development.