“His magnum opus, prepared in association with {{w|Joseph Nelson Rose|J. N. Rose}}, is the “{{w|The Cactaceae}}”, a four volume, copiously illustrated monograph of this most difficult plant family, published by the {{w|Carnegie Institution for Science|Carnegie Institution of Washington}}, 1919-23. In this work 124 genera and about 1,237 species of this perplexing family are described. No matter what future botanists may attempt or achieve in their consideration of this great family of plants, this Britton and Rose monograph forms a datum plane from which all future work must proceed.”