 de Candolle spent the rest of his life in an attempt to elaborate and complete his natural system of botanical <unk> de Candolle published initial work in his Regni <unk> systema naturale , but after two volumes he realized he could not complete the project on such a large scale . Consequently , he began his less extensive Prodromus Systematis Naturalis Regni Vegetabilis in 1824 . However , he was able to finish only seven volumes , or two @-@ thirds of the whole . Even so , he was able to characterize over one hundred families of plants , helping to lay the empirical basis of general botany . Although de Candolle 's main focus was botany , throughout his career he also dabbled in fields related to botany , such as phytogeography , agronomy , paleontology , medical botany , and economic botany . 
