Ainsworth & Bisby's Dictionary of the Fungi by DL Hawksworth, PM Kirk, BC Sutton, and DN Pegler. A well-known reference work on fungi, now in its 10th ed. 2008 and first published in 1943, providing definitions or explanations for terms and generic names of interest to mycologists. Coverage is of fungi, lichens, mushrooms, slime moulds, water moulds, and yeasts. Most entries include literature references. This edition contains a key to fungal families. A tribute to Ainsworth and his 60-year career appeared in Mycologia 91(4):714-719 July-August 1999. location

Bradley Bibliography: a guide to the literature of the woody plants of the world published before the beginning of the Twentieth Century by Alfred Rehder (Publications of the Arnold Arboretum, no. 3). This is a 5-volume set consisting of references to literature (books, pamphlets, articles) on woody plants, from any language through 1900. Entries are arranged by volumes 1 and 2: dendrology, 3: arboriculture, 4: forestry and volume 5 contains an author, title and keyword index. 1911 location

Encyclopedia of Life Sciences (eLS). Multi-volume set from Wiley. Key subject areas: biochemistry, cell biology, developmental biology, ecology, evolution and diversity of life, genetics, molecular biology, immunology, microbiology, neuroscience, plant science, structural biology, virology. 

PubAg Agricultural literature database from USDA National Agricultural Library. Cites to USDA-authored, peer-reviewed agricultural research. Over 42,227 full-text articles. Site includes NAL Agricultural Thesaurus.

Toxic Plants of North America by George E. Burrows and Ronald J. Tyrl 2nd ed. 2013 location Includes a glossary and some illustrations.