 de Candolle spent the rest of his life in an attempt to elaborate and complete his natural system of botanical classification. de Candolle published initial work in his Regni vegetabillis 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 . 
