Iter plantarum investigationis ergo susceptum a decem Sociis in Agrum Cantianum, anno Dom. 1629, Julii 13. Ericetum Hamstedianum sive Plantarum ibi crescentium observatio habita, anno eodem I. Augusti. Descripta studio, & opera Thomæ Iohnsoni.

Johnson, an apothecary published this record of what he collected during a herb-collecting excursion conducted on July 13, 1629, with an appendix recounting the results of a second excursion on August 1. This was the first local catalogue of plants published in England. It has also been called an early work in urban ecology.