A rediscovered work of Karel B. Presl and other sins of his youth

The authors announce the rediscovery at the Library of the Botanical Garden of Naples of a document by Karel B. Presl about the flora of Sicily (southern Italy), i.e., (the possible proofs of) the first issue of the Prodromus to his Flora Sicula, after 200 years from its preparation. This document, for reasons unknown, was not widely distributed to scientific institutions and, therefore, cannot be considered as published; in addition, it has been neglected until now, so that it is missing from Presl's bibliography. In spite of this, various botanists of the 19th century refer to this work for protologues. The booklet is bound together with the well-known first volume of Presl's Flora Sicula, and lacks a title page; consequently, direct information about title, date and possible place of publication are not available. Nevertheless, analyzing other contributions by the same scholar and also biographic and bibliographic information, the authors reconstruct the chronology of the booklet and formulate hypotheses on its origin and about the possible reasons for the choice of not publishing it. The Prodromus is also compared to other Presl publications on the Sicilian flora, often poorly known or forgotten, and especially to his dissertation. Three appendices report a list of the taxa present in these early works by Presl, and various nomenclatural notes.