Usher is an author of A Dictionary Of Botany (Pb 2005) .
<p><span style="color: rgb(33, 37, 41); font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Liberation Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji"; letter-spacing: 0.7px;">This work has been compiled to meet the needs of university students and grammar school pupils. In an attempt to achieve this terms which are used in soil-science statistics and biochemistry have been incorporated as well as those particular to botany. The problems of plant taxonomy are so immense that to include the various differences described by different authors would involve writing several volumes. A line had to be drawn somewhere and the following system has therefore been adopted. In the text the sign = means that the terms are synonymous e.g. SWARM SPORE = ZOOSPORE but See means that the term is referred to in the text indicated e.g. CROSS BREEDING See Cross. A dictionary is hardly an original work but rather a collection from the works of other writers.</span><br></p>